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insert.c

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.270 2009/07/24 17:58:53 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Generate code that will open a table for reading.
*/
void sqlite3OpenTable(
  Parse *p,       /* Generate code into this VDBE */
  int iCur,       /* The cursor number of the table */
  int iDb,        /* The database index in sqlite3.aDb[] */
  Table *pTab,    /* The table to be opened */
  int opcode      /* OP_OpenRead or OP_OpenWrite */
){
  Vdbe *v;
  if( IsVirtual(pTab) ) return;
  v = sqlite3GetVdbe(p);
  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
  sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite)?1:0, pTab->zName);
  sqlite3VdbeAddOp3(v, opcode, iCur, pTab->tnum, iDb);
  sqlite3VdbeChangeP4(v, -1, SQLITE_INT_TO_PTR(pTab->nCol), P4_INT32);
  VdbeComment((v, "%s", pTab->zName));
}

/*
** Return a pointer to the column affinity string associated with index
** pIdx. A column affinity string has one character for each column in 
** the table, according to the affinity of the column:
**
**  Character      Column affinity
**  ------------------------------
**  'a'            TEXT
**  'b'            NONE
**  'c'            NUMERIC
**  'd'            INTEGER
**  'e'            REAL
**
** An extra 'b' is appended to the end of the string to cover the
** rowid that appears as the last column in every index.
**
** Memory for the buffer containing the column index affinity string
** is managed along with the rest of the Index structure. It will be
** released when sqlite3DeleteIndex() is called.
*/
const char *sqlite3IndexAffinityStr(Vdbe *v, Index *pIdx){
  if( !pIdx->zColAff ){
    /* The first time a column affinity string for a particular index is
    ** required, it is allocated and populated here. It is then stored as
    ** a member of the Index structure for subsequent use.
    **
    ** The column affinity string will eventually be deleted by
    ** sqliteDeleteIndex() when the Index structure itself is cleaned
    ** up.
    */
    int n;
    Table *pTab = pIdx->pTable;
    sqlite3 *db = sqlite3VdbeDb(v);
    pIdx->zColAff = (char *)sqlite3Malloc(pIdx->nColumn+2);
    if( !pIdx->zColAff ){
      db->mallocFailed = 1;
      return 0;
    }
    for(n=0; n<pIdx->nColumn; n++){
      pIdx->zColAff[n] = pTab->aCol[pIdx->aiColumn[n]].affinity;
    }
    pIdx->zColAff[n++] = SQLITE_AFF_NONE;
    pIdx->zColAff[n] = 0;
  }
 
  return pIdx->zColAff;
}

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for table pTab. A column affinity string has one character
** for each column indexed by the index, according to the affinity of the
** column:
**
**  Character      Column affinity
**  ------------------------------
**  'a'            TEXT
**  'b'            NONE
**  'c'            NUMERIC
**  'd'            INTEGER
**  'e'            REAL
*/
void sqlite3TableAffinityStr(Vdbe *v, Table *pTab){
  /* The first time a column affinity string for a particular table
  ** is required, it is allocated and populated here. It is then 
  ** stored as a member of the Table structure for subsequent use.
  **
  ** The column affinity string will eventually be deleted by
  ** sqlite3DeleteTable() when the Table structure itself is cleaned up.
  */
  if( !pTab->zColAff ){
    char *zColAff;
    int i;
    sqlite3 *db = sqlite3VdbeDb(v);

    zColAff = (char *)sqlite3Malloc(pTab->nCol+1);
    if( !zColAff ){
      db->mallocFailed = 1;
      return;
    }

    for(i=0; i<pTab->nCol; i++){
      zColAff[i] = pTab->aCol[i].affinity;
    }
    zColAff[pTab->nCol] = '\0';

    pTab->zColAff = zColAff;
  }

  sqlite3VdbeChangeP4(v, -1, pTab->zColAff, 0);
}

/*
** Return non-zero if the table pTab in database iDb or any of its indices
** have been opened at any point in the VDBE program beginning at location
** iStartAddr throught the end of the program.  This is used to see if 
** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can 
** run without using temporary table for the results of the SELECT. 
*/
static int readsTable(Parse *p, int iStartAddr, int iDb, Table *pTab){
  Vdbe *v = sqlite3GetVdbe(p);
  int i;
  int iEnd = sqlite3VdbeCurrentAddr(v);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
#endif

  for(i=iStartAddr; i<iEnd; i++){
    VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
    assert( pOp!=0 );
    if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
      Index *pIndex;
      int tnum = pOp->p2;
      if( tnum==pTab->tnum ){
        return 1;
      }
      for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
        if( tnum==pIndex->tnum ){
          return 1;
        }
      }
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
      assert( pOp->p4.pVtab!=0 );
      assert( pOp->p4type==P4_VTAB );
      return 1;
    }
#endif
  }
  return 0;
}

#ifndef SQLITE_OMIT_AUTOINCREMENT
/*
** Locate or create an AutoincInfo structure associated with table pTab
** which is in database iDb.  Return the register number for the register
** that holds the maximum rowid.
**
** There is at most one AutoincInfo structure per table even if the
** same table is autoincremented multiple times due to inserts within
** triggers.  A new AutoincInfo structure is created if this is the
** first use of table pTab.  On 2nd and subsequent uses, the original
** AutoincInfo structure is used.
**
** Three memory locations are allocated:
**
**   (1)  Register to hold the name of the pTab table.
**   (2)  Register to hold the maximum ROWID of pTab.
**   (3)  Register to hold the rowid in sqlite_sequence of pTab
**
** The 2nd register is the one that is returned.  That is all the
** insert routine needs to know about.
*/
static int autoIncBegin(
  Parse *pParse,      /* Parsing context */
  int iDb,            /* Index of the database holding pTab */
  Table *pTab         /* The table we are writing to */
){
  int memId = 0;      /* Register holding maximum rowid */
  if( pTab->tabFlags & TF_Autoincrement ){
    Parse *pToplevel = sqlite3ParseToplevel(pParse);
    AutoincInfo *pInfo;

    pInfo = pToplevel->pAinc;
    while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
    if( pInfo==0 ){
      pInfo = sqlite3DbMallocRaw(pParse->db, sizeof(*pInfo));
      if( pInfo==0 ) return 0;
      pInfo->pNext = pToplevel->pAinc;
      pToplevel->pAinc = pInfo;
      pInfo->pTab = pTab;
      pInfo->iDb = iDb;
      pToplevel->nMem++;                  /* Register to hold name of table */
      pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
      pToplevel->nMem++;                  /* Rowid in sqlite_sequence */
    }
    memId = pInfo->regCtr;
  }
  return memId;
}

/*
** This routine generates code that will initialize all of the
** register used by the autoincrement tracker.  
*/
void sqlite3AutoincrementBegin(Parse *pParse){
  AutoincInfo *p;            /* Information about an AUTOINCREMENT */
  sqlite3 *db = pParse->db;  /* The database connection */
  Db *pDb;                   /* Database only autoinc table */
  int memId;                 /* Register holding max rowid */
  int addr;                  /* A VDBE address */
  Vdbe *v = pParse->pVdbe;   /* VDBE under construction */

  /* This routine is never called during trigger-generation.  It is
  ** only called from the top-level */
  assert( pParse->pTriggerTab==0 );
  assert( pParse==sqlite3ParseToplevel(pParse) );

  assert( v );   /* We failed long ago if this is not so */
  for(p = pParse->pAinc; p; p = p->pNext){
    pDb = &db->aDb[p->iDb];
    memId = p->regCtr;
    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
    addr = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeAddOp4(v, OP_String8, 0, memId-1, 0, p->pTab->zName, 0);
    sqlite3VdbeAddOp2(v, OP_Rewind, 0, addr+9);
    sqlite3VdbeAddOp3(v, OP_Column, 0, 0, memId);
    sqlite3VdbeAddOp3(v, OP_Ne, memId-1, addr+7, memId);
    sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);
    sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
    sqlite3VdbeAddOp3(v, OP_Column, 0, 1, memId);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr+9);
    sqlite3VdbeAddOp2(v, OP_Next, 0, addr+2);
    sqlite3VdbeAddOp2(v, OP_Integer, 0, memId);
    sqlite3VdbeAddOp0(v, OP_Close);
  }
}

/*
** Update the maximum rowid for an autoincrement calculation.
**
** This routine should be called when the top of the stack holds a
** new rowid that is about to be inserted.  If that new rowid is
** larger than the maximum rowid in the memId memory cell, then the
** memory cell is updated.  The stack is unchanged.
*/
static void autoIncStep(Parse *pParse, int memId, int regRowid){
  if( memId>0 ){
    sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
  }
}

/*
** This routine generates the code needed to write autoincrement
** maximum rowid values back into the sqlite_sequence register.
** Every statement that might do an INSERT into an autoincrement
** table (either directly or through triggers) needs to call this
** routine just before the "exit" code.
*/
void sqlite3AutoincrementEnd(Parse *pParse){
  AutoincInfo *p;
  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;

  assert( v );
  for(p = pParse->pAinc; p; p = p->pNext){
    Db *pDb = &db->aDb[p->iDb];
    int j1, j2, j3, j4, j5;
    int iRec;
    int memId = p->regCtr;

    iRec = sqlite3GetTempReg(pParse);
    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
    j1 = sqlite3VdbeAddOp1(v, OP_NotNull, memId+1);
    j2 = sqlite3VdbeAddOp0(v, OP_Rewind);
    j3 = sqlite3VdbeAddOp3(v, OP_Column, 0, 0, iRec);
    j4 = sqlite3VdbeAddOp3(v, OP_Eq, memId-1, 0, iRec);
    sqlite3VdbeAddOp2(v, OP_Next, 0, j3);
    sqlite3VdbeJumpHere(v, j2);
    sqlite3VdbeAddOp2(v, OP_NewRowid, 0, memId+1);
    j5 = sqlite3VdbeAddOp0(v, OP_Goto);
    sqlite3VdbeJumpHere(v, j4);
    sqlite3VdbeAddOp2(v, OP_Rowid, 0, memId+1);
    sqlite3VdbeJumpHere(v, j1);
    sqlite3VdbeJumpHere(v, j5);
    sqlite3VdbeAddOp3(v, OP_MakeRecord, memId-1, 2, iRec);
    sqlite3VdbeAddOp3(v, OP_Insert, 0, iRec, memId+1);
    sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
    sqlite3VdbeAddOp0(v, OP_Close);
    sqlite3ReleaseTempReg(pParse, iRec);
  }
}
#else
/*
** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
** above are all no-ops
*/
# define autoIncBegin(A,B,C) (0)
# define autoIncStep(A,B,C)
#endif /* SQLITE_OMIT_AUTOINCREMENT */


/* Forward declaration */
static int xferOptimization(
  Parse *pParse,        /* Parser context */
  Table *pDest,         /* The table we are inserting into */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  int onError,          /* How to handle constraint errors */
  int iDbDest           /* The database of pDest */
);

/*
** This routine is call to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST)
**    insert into TABLE (IDLIST) select
**
** The IDLIST following the table name is always optional.  If omitted,
** then a list of all columns for the table is substituted.  The IDLIST
** appears in the pColumn parameter.  pColumn is NULL if IDLIST is omitted.
**
** The pList parameter holds EXPRLIST in the first form of the INSERT
** statement above, and pSelect is NULL.  For the second form, pList is
** NULL and pSelect is a pointer to the select statement used to generate
** data for the insert.
**
** The code generated follows one of four templates.  For a simple
** select with data coming from a VALUES clause, the code executes
** once straight down through.  Pseudo-code follows (we call this
** the "1st template"):
**
**         open write cursor to <table> and its indices
**         puts VALUES clause expressions onto the stack
**         write the resulting record into <table>
**         cleanup
**
** The three remaining templates assume the statement is of the form
**
**   INSERT INTO <table> SELECT ...
**
** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
** in other words if the SELECT pulls all columns from a single table
** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
** if <table2> and <table1> are distinct tables but have identical
** schemas, including all the same indices, then a special optimization
** is invoked that copies raw records from <table2> over to <table1>.
** See the xferOptimization() function for the implementation of this
** template.  This is the 2nd template.
**
**         open a write cursor to <table>
**         open read cursor on <table2>
**         transfer all records in <table2> over to <table>
**         close cursors
**         foreach index on <table>
**           open a write cursor on the <table> index
**           open a read cursor on the corresponding <table2> index
**           transfer all records from the read to the write cursors
**           close cursors
**         end foreach
**
** The 3rd template is for when the second template does not apply
** and the SELECT clause does not read from <table> at any time.
** The generated code follows this template:
**
**         EOF <- 0
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the rows in the SELECT
**           load values into registers R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT
**         EOF <- 1
**         yield X
**         goto A
**      B: open write cursor to <table> and its indices
**      C: yield X
**         if EOF goto D
**         insert the select result into <table> from R..R+n
**         goto C
**      D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT.  In the third form,
** we have to use a intermediate table to store the results of
** the select.  The template is like this:
**
**         EOF <- 0
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           load value into register R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT
**         EOF <- 1
**         yield X
**         halt-error
**      B: open temp table
**      L: yield X
**         if EOF goto M
**         insert row from R..R+n into temp table
**         goto L
**      M: open write cursor to <table> and its indices
**         rewind temp table
**      C: loop over rows of intermediate table
**           transfer values form intermediate table into <table>
**         end loop
**      D: cleanup
*/
void sqlite3Insert(
  Parse *pParse,        /* Parser context */
  SrcList *pTabList,    /* Name of table into which we are inserting */
  ExprList *pList,      /* List of values to be inserted */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  IdList *pColumn,      /* Column names corresponding to IDLIST. */
  int onError           /* How to handle constraint errors */
){
  sqlite3 *db;          /* The main database structure */
  Table *pTab;          /* The table to insert into.  aka TABLE */
  char *zTab;           /* Name of the table into which we are inserting */
  const char *zDb;      /* Name of the database holding this table */
  int i, j, idx;        /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int nColumn;          /* Number of columns in the data */
  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
  int baseCur = 0;      /* VDBE Cursor number for pTab */
  int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
  int endOfLoop;        /* Label for the end of the insertion loop */
  int useTempTable = 0; /* Store SELECT results in intermediate table */
  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
  int addrInsTop = 0;   /* Jump to label "D" */
  int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
  int addrSelect = 0;   /* Address of coroutine that implements the SELECT */
  SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
  int iDb;              /* Index of database holding TABLE */
  Db *pDb;              /* The database containing table being inserted into */
  int appendFlag = 0;   /* True if the insert is likely to be an append */

  /* Register allocations */
  int regFromSelect = 0;/* Base register for data coming from SELECT */
  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
  int regRowCount = 0;  /* Memory cell used for the row counter */
  int regIns;           /* Block of regs holding rowid+data being inserted */
  int regRowid;         /* registers holding insert rowid */
  int regData;          /* register holding first column to insert */
  int regRecord;        /* Holds the assemblied row record */
  int regEof = 0;       /* Register recording end of SELECT data */
  int *aRegIdx = 0;     /* One register allocated to each index */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                 /* True if attempting to insert into a view */
  Trigger *pTrigger;          /* List of triggers on pTab, if required */
  int tmask;                  /* Mask of trigger times */
#endif

  db = pParse->db;
  memset(&dest, 0, sizeof(dest));
  if( pParse->nErr || db->mallocFailed ){
    goto insert_cleanup;
  }

  /* Locate the table into which we will be inserting new information.
  */
  assert( pTabList->nSrc==1 );
  zTab = pTabList->a[0].zName;
  if( NEVER(zTab==0) ) goto insert_cleanup;
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ){
    goto insert_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  pDb = &db->aDb[iDb];
  zDb = pDb->zName;
  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
    goto insert_cleanup;
  }

  /* Figure out if we have any triggers and if the table being
  ** inserted into is a view
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
  isView = pTab->pSelect!=0;
#else
# define pTrigger 0
# define tmask 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif
  assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );

  /* If pTab is really a view, make sure it has been initialized.
  ** ViewGetColumnNames() is a no-op if pTab is not a view (or virtual 
  ** module table).
  */
  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto insert_cleanup;
  }

  /* Ensure that:
  *  (a) the table is not read-only, 
  *  (b) that if it is a view then ON INSERT triggers exist
  */
  if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
    goto insert_cleanup;
  }

  /* Allocate a VDBE
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);

#ifndef SQLITE_OMIT_XFER_OPT
  /* If the statement is of the form
  **
  **       INSERT INTO <table1> SELECT * FROM <table2>;
  **
  ** Then special optimizations can be applied that make the transfer
  ** very fast and which reduce fragmentation of indices.
  **
  ** This is the 2nd template.
  */
  if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
    assert( !pTrigger );
    assert( pList==0 );
    goto insert_end;
  }
#endif /* SQLITE_OMIT_XFER_OPT */

  /* If this is an AUTOINCREMENT table, look up the sequence number in the
  ** sqlite_sequence table and store it in memory cell regAutoinc.
  */
  regAutoinc = autoIncBegin(pParse, iDb, pTab);

  /* Figure out how many columns of data are supplied.  If the data
  ** is coming from a SELECT statement, then generate a co-routine that
  ** produces a single row of the SELECT on each invocation.  The
  ** co-routine is the common header to the 3rd and 4th templates.
  */
  if( pSelect ){
    /* Data is coming from a SELECT.  Generate code to implement that SELECT
    ** as a co-routine.  The code is common to both the 3rd and 4th
    ** templates:
    **
    **         EOF <- 0
    **         X <- A
    **         goto B
    **      A: setup for the SELECT
    **         loop over the tables in the SELECT
    **           load value into register R..R+n
    **           yield X
    **         end loop
    **         cleanup after the SELECT
    **         EOF <- 1
    **         yield X
    **         halt-error
    **
    ** On each invocation of the co-routine, it puts a single row of the
    ** SELECT result into registers dest.iMem...dest.iMem+dest.nMem-1.
    ** (These output registers are allocated by sqlite3Select().)  When
    ** the SELECT completes, it sets the EOF flag stored in regEof.
    */
    int rc, j1;

    regEof = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof);      /* EOF <- 0 */
    VdbeComment((v, "SELECT eof flag"));
    sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
    addrSelect = sqlite3VdbeCurrentAddr(v)+2;
    sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
    j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
    VdbeComment((v, "Jump over SELECT coroutine"));

    /* Resolve the expressions in the SELECT statement and execute it. */
    rc = sqlite3Select(pParse, pSelect, &dest);
    assert( pParse->nErr==0 || rc );
    if( rc || NEVER(pParse->nErr) || db->mallocFailed ){
      goto insert_cleanup;
    }
    sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);         /* EOF <- 1 */
    sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);   /* yield X */
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
    VdbeComment((v, "End of SELECT coroutine"));
    sqlite3VdbeJumpHere(v, j1);                          /* label B: */

    regFromSelect = dest.iMem;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
    assert( dest.nMem==nColumn );

    /* Set useTempTable to TRUE if the result of the SELECT statement
    ** should be written into a temporary table (template 4).  Set to
    ** FALSE if each* row of the SELECT can be written directly into
    ** the destination table (template 3).
    **
    ** A temp table must be used if the table being updated is also one
    ** of the tables being read by the SELECT statement.  Also use a 
    ** temp table in the case of row triggers.
    */
    if( pTrigger || readsTable(pParse, addrSelect, iDb, pTab) ){
      useTempTable = 1;
    }

    if( useTempTable ){
      /* Invoke the coroutine to extract information from the SELECT
      ** and add it to a transient table srcTab.  The code generated
      ** here is from the 4th template:
      **
      **      B: open temp table
      **      L: yield X
      **         if EOF goto M
      **         insert row from R..R+n into temp table
      **         goto L
      **      M: ...
      */
      int regRec;          /* Register to hold packed record */
      int regTempRowid;    /* Register to hold temp table ROWID */
      int addrTop;         /* Label "L" */
      int addrIf;          /* Address of jump to M */

      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regTempRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
      addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrIf);
      sqlite3ReleaseTempReg(pParse, regRec);
      sqlite3ReleaseTempReg(pParse, regTempRowid);
    }
  }else{
    /* This is the case if the data for the INSERT is coming from a VALUES
    ** clause
    */
    NameContext sNC;
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    srcTab = -1;
    assert( useTempTable==0 );
    nColumn = pList ? pList->nExpr : 0;
    for(i=0; i<nColumn; i++){
      if( sqlite3ResolveExprNames(&sNC, pList->a[i].pExpr) ){
        goto insert_cleanup;
      }
    }
  }

  /* Make sure the number of columns in the source data matches the number
  ** of columns to be inserted into the table.
  */
  if( IsVirtual(pTab) ){
    for(i=0; i<pTab->nCol; i++){
      nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
    }
  }
  if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
    sqlite3ErrorMsg(pParse, 
       "table %S has %d columns but %d values were supplied",
       pTabList, 0, pTab->nCol-nHidden, nColumn);
    goto insert_cleanup;
  }
  if( pColumn!=0 && nColumn!=pColumn->nId ){
    sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
    goto insert_cleanup;
  }

  /* If the INSERT statement included an IDLIST term, then make sure
  ** all elements of the IDLIST really are columns of the table and 
  ** remember the column indices.
  **
  ** If the table has an INTEGER PRIMARY KEY column and that column
  ** is named in the IDLIST, then record in the keyColumn variable
  ** the index into IDLIST of the primary key column.  keyColumn is
  ** the index of the primary key as it appears in IDLIST, not as
  ** is appears in the original table.  (The index of the primary
  ** key in the original table is pTab->iPKey.)
  */
  if( pColumn ){
    for(i=0; i<pColumn->nId; i++){
      pColumn->a[i].idx = -1;
    }
    for(i=0; i<pColumn->nId; i++){
      for(j=0; j<pTab->nCol; j++){
        if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
          pColumn->a[i].idx = j;
          if( j==pTab->iPKey ){
            keyColumn = i;
          }
          break;
        }
      }
      if( j>=pTab->nCol ){
        if( sqlite3IsRowid(pColumn->a[i].zName) ){
          keyColumn = i;
        }else{
          sqlite3ErrorMsg(pParse, "table %S has no column named %s",
              pTabList, 0, pColumn->a[i].zName);
          pParse->nErr++;
          goto insert_cleanup;
        }
      }
    }
  }

  /* If there is no IDLIST term but the table has an integer primary
  ** key, the set the keyColumn variable to the primary key column index
  ** in the original table definition.
  */
  if( pColumn==0 && nColumn>0 ){
    keyColumn = pTab->iPKey;
  }
    
  /* Initialize the count of rows to be inserted
  */
  if( db->flags & SQLITE_CountRows ){
    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  /* If this is not a view, open the table and and all indices */
  if( !isView ){
    int nIdx;

    baseCur = pParse->nTab;
    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, baseCur, OP_OpenWrite);
    aRegIdx = sqlite3DbMallocRaw(db, sizeof(int)*(nIdx+1));
    if( aRegIdx==0 ){
      goto insert_cleanup;
    }
    for(i=0; i<nIdx; i++){
      aRegIdx[i] = ++pParse->nMem;
    }
  }

  /* This is the top of the main insertion loop */
  if( useTempTable ){
    /* This block codes the top of loop only.  The complete loop is the
    ** following pseudocode (template 4):
    **
    **         rewind temp table
    **      C: loop over rows of intermediate table
    **           transfer values form intermediate table into <table>
    **         end loop
    **      D: ...
    */
    addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab);
    addrCont = sqlite3VdbeCurrentAddr(v);
  }else if( pSelect ){
    /* This block codes the top of loop only.  The complete loop is the
    ** following pseudocode (template 3):
    **
    **      C: yield X
    **         if EOF goto D
    **         insert the select result into <table> from R..R+n
    **         goto C
    **      D: ...
    */
    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
    addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
  }

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRecord = ++pParse->nMem;
  regRowid = regIns = pParse->nMem+1;
  pParse->nMem += pTab->nCol + 1;
  if( IsVirtual(pTab) ){
    regRowid++;
    pParse->nMem++;
  }
  regData = regRowid+1;

  /* Run the BEFORE and INSTEAD OF triggers, if there are any
  */
  endOfLoop = sqlite3VdbeMakeLabel(v);
  if( tmask & TRIGGER_BEFORE ){
    int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);

    /* build the NEW.* reference row.  Note that if there is an INTEGER
    ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
    ** translated into a unique ID for the row.  But on a BEFORE trigger,
    ** we do not know what the unique ID will be (because the insert has
    ** not happened yet) so we substitute a rowid of -1
    */
    if( keyColumn<0 ){
      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
    }else{
      int j1;
      if( useTempTable ){
        sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regCols);
      }else{
        assert( pSelect==0 );  /* Otherwise useTempTable is true */
        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regCols);
      }
      j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols);
      sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
      sqlite3VdbeJumpHere(v, j1);
      sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols);
    }

    /* Cannot have triggers on a virtual table. If it were possible,
    ** this block would have to account for hidden column.
    */
    assert( !IsVirtual(pTab) );

    /* Create the new column data
    */
    for(i=0; i<pTab->nCol; i++){
      if( pColumn==0 ){
        j = i;
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==i ) break;
        }
      }
      if( pColumn && j>=pColumn->nId ){
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
      }else if( useTempTable ){
        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1); 
      }else{
        assert( pSelect==0 ); /* Otherwise useTempTable is true */
        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
      }
    }

    /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
    ** do not attempt any conversions before assembling the record.
    ** If this is a real table, attempt conversions as required by the
    ** table column affinities.
    */
    if( !isView ){
      sqlite3VdbeAddOp2(v, OP_Affinity, regCols+1, pTab->nCol);
      sqlite3TableAffinityStr(v, pTab);
    }

    /* Fire BEFORE or INSTEAD OF triggers */
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE, 
        pTab, -1, regCols-pTab->nCol-1, onError, endOfLoop);

    sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
  }

  /* Push the record number for the new entry onto the stack.  The
  ** record number is a randomly generate integer created by NewRowid
  ** except when the table has an INTEGER PRIMARY KEY column, in which
  ** case the record number is the same as that column. 
  */
  if( !isView ){
    if( IsVirtual(pTab) ){
      /* The row that the VUpdate opcode will delete: none */
      sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
    }
    if( keyColumn>=0 ){
      if( useTempTable ){
        sqlite3VdbeAddOp3(v, OP_Column, srcTab, keyColumn, regRowid);
      }else if( pSelect ){
        sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+keyColumn, regRowid);
      }else{
        VdbeOp *pOp;
        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, regRowid);
        pOp = sqlite3VdbeGetOp(v, -1);
        if( ALWAYS(pOp) && pOp->opcode==OP_Null && !IsVirtual(pTab) ){
          appendFlag = 1;
          pOp->opcode = OP_NewRowid;
          pOp->p1 = baseCur;
          pOp->p2 = regRowid;
          pOp->p3 = regAutoinc;
        }
      }
      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
      ** to generate a unique primary key value.
      */
      if( !appendFlag ){
        int j1;
        if( !IsVirtual(pTab) ){
          j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid);
          sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
          sqlite3VdbeJumpHere(v, j1);
        }else{
          j1 = sqlite3VdbeCurrentAddr(v);
          sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, j1+2);
        }
        sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid);
      }
    }else if( IsVirtual(pTab) ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
    }else{
      sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
      appendFlag = 1;
    }
    autoIncStep(pParse, regAutoinc, regRowid);

    /* Push onto the stack, data for all columns of the new entry, beginning
    ** with the first column.
    */
    nHidden = 0;
    for(i=0; i<pTab->nCol; i++){
      int iRegStore = regRowid+1+i;
      if( i==pTab->iPKey ){
        /* The value of the INTEGER PRIMARY KEY column is always a NULL.
        ** Whenever this column is read, the record number will be substituted
        ** in its place.  So will fill this column with a NULL to avoid
        ** taking up data space with information that will never be used. */
        sqlite3VdbeAddOp2(v, OP_Null, 0, iRegStore);
        continue;
      }
      if( pColumn==0 ){
        if( IsHiddenColumn(&pTab->aCol[i]) ){
          assert( IsVirtual(pTab) );
          j = -1;
          nHidden++;
        }else{
          j = i - nHidden;
        }
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==i ) break;
        }
      }
      if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, iRegStore);
      }else if( useTempTable ){
        sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore); 
      }else if( pSelect ){
        sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
      }else{
        sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
      }
    }

    /* Generate code to check constraints and generate index keys and
    ** do the insertion.
    */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
      sqlite3MayAbort(pParse);
    }else
#endif
    {
      int isReplace;    /* Set to true if constraints may cause a replace */
      sqlite3GenerateConstraintChecks(pParse, pTab, baseCur, regIns, aRegIdx,
          keyColumn>=0, 0, onError, endOfLoop, &isReplace
      );
      sqlite3CompleteInsertion(
          pParse, pTab, baseCur, regIns, aRegIdx, 0, appendFlag, isReplace==0
      );
    }
  }

  /* Update the count of rows that are inserted
  */
  if( (db->flags & SQLITE_CountRows)!=0 ){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
  }

  if( pTrigger ){
    /* Code AFTER triggers */
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER, 
        pTab, -1, regData-2-pTab->nCol, onError, endOfLoop);
  }

  /* The bottom of the main insertion loop, if the data source
  ** is a SELECT statement.
  */
  sqlite3VdbeResolveLabel(v, endOfLoop);
  if( useTempTable ){
    sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont);
    sqlite3VdbeJumpHere(v, addrInsTop);
    sqlite3VdbeAddOp1(v, OP_Close, srcTab);
  }else if( pSelect ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrCont);
    sqlite3VdbeJumpHere(v, addrInsTop);
  }

  if( !IsVirtual(pTab) && !isView ){
    /* Close all tables opened */
    sqlite3VdbeAddOp1(v, OP_Close, baseCur);
    for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
      sqlite3VdbeAddOp1(v, OP_Close, idx+baseCur);
    }
  }

insert_end:
  /* Update the sqlite_sequence table by storing the content of the
  ** maximum rowid counter values recorded while inserting into
  ** autoincrement tables.
  */
  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
    sqlite3AutoincrementEnd(pParse);
  }

  /*
  ** Return the number of rows inserted. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
    sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
  }

insert_cleanup:
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprListDelete(db, pList);
  sqlite3SelectDelete(db, pSelect);
  sqlite3IdListDelete(db, pColumn);
  sqlite3DbFree(db, aRegIdx);
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE.
**
** The input is a range of consecutive registers as follows:
**
**    1.  The rowid of the row after the update.
**
**    2.  The data in the first column of the entry after the update.
**
**    i.  Data from middle columns...
**
**    N.  The data in the last column of the entry after the update.
**
** The regRowid parameter is the index of the register containing (1).
**
** If isUpdate is true and rowidChng is non-zero, then rowidChng contains
** the address of a register containing the rowid before the update takes
** place. isUpdate is true for UPDATEs and false for INSERTs. If isUpdate
** is false, indicating an INSERT statement, then a non-zero rowidChng 
** indicates that the rowid was explicitly specified as part of the
** INSERT statement. If rowidChng is false, it means that  the rowid is
** computed automatically in an insert or that the rowid value is not 
** modified by an update.
**
** The code generated by this routine store new index entries into
** registers identified by aRegIdx[].  No index entry is created for
** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
** the same as the order of indices on the linked list of indices
** attached to the table.
**
** This routine also generates code to check constraints.  NOT NULL,
** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
** then the appropriate action is performed.  There are five possible
** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
**
**  Constraint type  Action       What Happens
**  ---------------  ----------   ----------------------------------------
**  any              ROLLBACK     The current transaction is rolled back and
**                                sqlite3_exec() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.
**
**  any              ABORT        Back out changes from the current command
**                                only (do not do a complete rollback) then
**                                cause sqlite3_exec() to return immediately
**                                with SQLITE_CONSTRAINT.
**
**  any              FAIL         Sqlite_exec() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.  The
**                                transaction is not rolled back and any
**                                prior changes are retained.
**
**  any              IGNORE       The record number and data is popped from
**                                the stack and there is an immediate jump
**                                to label ignoreDest.
**
**  NOT NULL         REPLACE      The NULL value is replace by the default
**                                value for that column.  If the default value
**                                is NULL, the action is the same as ABORT.
**
**  UNIQUE           REPLACE      The other row that conflicts with the row
**                                being inserted is removed.
**
**  CHECK            REPLACE      Illegal.  The results in an exception.
**
** Which action to take is determined by the overrideError parameter.
** Or if overrideError==OE_Default, then the pParse->onError parameter
** is used.  Or if pParse->onError==OE_Default then the onError value
** for the constraint is used.
**
** The calling routine must open a read/write cursor for pTab with
** cursor number "baseCur".  All indices of pTab must also have open
** read/write cursors with cursor number baseCur+i for the i-th cursor.
** Except, if there is no possibility of a REPLACE action then
** cursors do not need to be open for indices where aRegIdx[i]==0.
*/
void sqlite3GenerateConstraintChecks(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int baseCur,        /* Index of a read/write cursor pointing at pTab */
  int regRowid,       /* Index of the range of input registers */
  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int rowidChng,      /* True if the rowid might collide with existing entry */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int overrideError,  /* Override onError to this if not OE_Default */
  int ignoreDest,     /* Jump to this label on an OE_Ignore resolution */
  int *pbMayReplace   /* OUT: Set to true if constraint may cause a replace */
){
  int i;              /* loop counter */
  Vdbe *v;            /* VDBE under constrution */
  int nCol;           /* Number of columns */
  int onError;        /* Conflict resolution strategy */
  int j1;             /* Addresss of jump instruction */
  int j2 = 0, j3;     /* Addresses of jump instructions */
  int regData;        /* Register containing first data column */
  int iCur;           /* Table cursor number */
  Index *pIdx;         /* Pointer to one of the indices */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int regOldRowid = (rowidChng && isUpdate) ? rowidChng : regRowid;

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;
  regData = regRowid + 1;

  /* Test all NOT NULL constraints.
  */
  for(i=0; i<nCol; i++){
    if( i==pTab->iPKey ){
      continue;
    }
    onError = pTab->aCol[i].notNull;
    if( onError==OE_None ) continue;
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }
    if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
      onError = OE_Abort;
    }
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Abort:
        sqlite3MayAbort(pParse);
      case OE_Rollback:
      case OE_Fail: {
        char *zMsg;
        j1 = sqlite3VdbeAddOp3(v, OP_HaltIfNull,
                                  SQLITE_CONSTRAINT, onError, regData+i);
        zMsg = sqlite3MPrintf(pParse->db, "%s.%s may not be NULL",
                              pTab->zName, pTab->aCol[i].zName);
        sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
        break;
      }
      case OE_Ignore: {
        sqlite3VdbeAddOp2(v, OP_IsNull, regData+i, ignoreDest);
        break;
      }
      default: {
        assert( onError==OE_Replace );
        j1 = sqlite3VdbeAddOp1(v, OP_NotNull, regData+i);
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regData+i);
        sqlite3VdbeJumpHere(v, j1);
        break;
      }
    }
  }

  /* Test all CHECK constraints
  */
#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
    int allOk = sqlite3VdbeMakeLabel(v);
    pParse->ckBase = regData;
    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, SQLITE_JUMPIFNULL);
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    if( onError==OE_Ignore ){
      sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
    }else{
      sqlite3HaltConstraint(pParse, onError, 0, 0);
    }
    sqlite3VdbeResolveLabel(v, allOk);
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If we have an INTEGER PRIMARY KEY, make sure the primary key
  ** of the new record does not previously exist.  Except, if this
  ** is an UPDATE and the primary key is not changing, that is OK.
  */
  if( rowidChng ){
    onError = pTab->keyConf;
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }
    
    if( onError!=OE_Replace || pTab->pIndex ){
      if( isUpdate ){
        j2 = sqlite3VdbeAddOp3(v, OP_Eq, regRowid, 0, rowidChng);
      }
      j3 = sqlite3VdbeAddOp3(v, OP_NotExists, baseCur, 0, regRowid);
      switch( onError ){
        default: {
          onError = OE_Abort;
          /* Fall thru into the next case */
        }
        case OE_Rollback:
        case OE_Abort:
        case OE_Fail: {
          sqlite3HaltConstraint(
            pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
          break;
        }
        case OE_Replace: {
          /* If there are DELETE triggers on this table and the
          ** recursive-triggers flag is set, call GenerateRowDelete() to
          ** remove the conflicting row from the the table. This will fire
          ** the triggers and remove both the table and index b-tree entries.
          **
          ** Otherwise, if there are no triggers or the recursive-triggers
          ** flag is not set, call GenerateRowIndexDelete(). This removes
          ** the index b-tree entries only. The table b-tree entry will be 
          ** replaced by the new entry when it is inserted.  */
          Trigger *pTrigger = 0;
          if( pParse->db->flags&SQLITE_RecTriggers ){
            pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
          }
          if( pTrigger ){
            sqlite3GenerateRowDelete(
                pParse, pTab, baseCur, regRowid, 0, pTrigger, OE_Replace
            );
          }else{
            sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
          }
          seenReplace = 1;
          break;
        }
        case OE_Ignore: {
          assert( seenReplace==0 );
          sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
          break;
        }
      }
      sqlite3VdbeJumpHere(v, j3);
      if( isUpdate ){
        sqlite3VdbeJumpHere(v, j2);
      }
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Add the new records to the indices as we go.
  */
  for(iCur=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, iCur++){
    int regIdx;
    int regR;

    if( aRegIdx[iCur]==0 ) continue;  /* Skip unused indices */

    /* Create a key for accessing the index entry */
    regIdx = sqlite3GetTempRange(pParse, pIdx->nColumn+1);
    for(i=0; i<pIdx->nColumn; i++){
      int idx = pIdx->aiColumn[i];
      if( idx==pTab->iPKey ){
        sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
      }else{
        sqlite3VdbeAddOp2(v, OP_SCopy, regData+idx, regIdx+i);
      }
    }
    sqlite3VdbeAddOp2(v, OP_SCopy, regRowid, regIdx+i);
    sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn+1, aRegIdx[iCur]);
    sqlite3VdbeChangeP4(v, -1, sqlite3IndexAffinityStr(v, pIdx), 0);
    sqlite3ExprCacheAffinityChange(pParse, regIdx, pIdx->nColumn+1);

    /* Find out what action to take in case there is an indexing conflict */
    onError = pIdx->onError;
    if( onError==OE_None ){ 
      sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);
      continue;  /* pIdx is not a UNIQUE index */
    }
    if( overrideError!=OE_Default ){
      onError = overrideError;
    }else if( onError==OE_Default ){
      onError = OE_Abort;
    }
    if( seenReplace ){
      if( onError==OE_Ignore ) onError = OE_Replace;
      else if( onError==OE_Fail ) onError = OE_Abort;
    }
    
    /* Check to see if the new index entry will be unique */
    regR = sqlite3GetTempReg(pParse);
    sqlite3VdbeAddOp2(v, OP_SCopy, regOldRowid, regR);
    j3 = sqlite3VdbeAddOp4(v, OP_IsUnique, baseCur+iCur+1, 0,
                           regR, SQLITE_INT_TO_PTR(regIdx),
                           P4_INT32);
    sqlite3ReleaseTempRange(pParse, regIdx, pIdx->nColumn+1);

    /* Generate code that executes if the new index entry is not unique */
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Rollback:
      case OE_Abort:
      case OE_Fail: {
        int j;
        StrAccum errMsg;
        const char *zSep;
        char *zErr;

        sqlite3StrAccumInit(&errMsg, 0, 0, 200);
        errMsg.db = pParse->db;
        zSep = pIdx->nColumn>1 ? "columns " : "column ";
        for(j=0; j<pIdx->nColumn; j++){
          char *zCol = pTab->aCol[pIdx->aiColumn[j]].zName;
          sqlite3StrAccumAppend(&errMsg, zSep, -1);
          zSep = ", ";
          sqlite3StrAccumAppend(&errMsg, zCol, -1);
        }
        sqlite3StrAccumAppend(&errMsg,
            pIdx->nColumn>1 ? " are not unique" : " is not unique", -1);
        zErr = sqlite3StrAccumFinish(&errMsg);
        sqlite3HaltConstraint(pParse, onError, zErr, 0);
        sqlite3DbFree(errMsg.db, zErr);
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      default: {
        Trigger *pTrigger = 0;
        assert( onError==OE_Replace );
        if( pParse->db->flags&SQLITE_RecTriggers ){
          pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
        }
        sqlite3GenerateRowDelete(
            pParse, pTab, baseCur, regR, 0, pTrigger, OE_Replace
        );
        seenReplace = 1;
        break;
      }
    }
    sqlite3VdbeJumpHere(v, j3);
    sqlite3ReleaseTempReg(pParse, regR);
  }

  if( pbMayReplace ){
    *pbMayReplace = seenReplace;
  }
}

/*
** This routine generates code to finish the INSERT or UPDATE operation
** that was started by a prior call to sqlite3GenerateConstraintChecks.
** A consecutive range of registers starting at regRowid contains the
** rowid and the content to be inserted.
**
** The arguments to this routine should be the same as the first six
** arguments to sqlite3GenerateConstraintChecks.
*/
void sqlite3CompleteInsertion(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int baseCur,        /* Index of a read/write cursor pointing at pTab */
  int regRowid,       /* Range of content */
  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int appendBias,     /* True if this is likely to be an append */
  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
){
  int i;
  Vdbe *v;
  int nIdx;
  Index *pIdx;
  u8 pik_flags;
  int regData;
  int regRec;

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
  for(i=nIdx-1; i>=0; i--){
    if( aRegIdx[i]==0 ) continue;
    sqlite3VdbeAddOp2(v, OP_IdxInsert, baseCur+i+1, aRegIdx[i]);
    if( useSeekResult ){
      sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
    }
  }
  regData = regRowid + 1;
  regRec = sqlite3GetTempReg(pParse);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
  sqlite3TableAffinityStr(v, pTab);
  sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
  }
  if( appendBias ){
    pik_flags |= OPFLAG_APPEND;
  }
  if( useSeekResult ){
    pik_flags |= OPFLAG_USESEEKRESULT;
  }
  sqlite3VdbeAddOp3(v, OP_Insert, baseCur, regRec, regRowid);
  if( !pParse->nested ){
    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
  }
  sqlite3VdbeChangeP5(v, pik_flags);
}

/*
** Generate code that will open cursors for a table and for all
** indices of that table.  The "baseCur" parameter is the cursor number used
** for the table.  Indices are opened on subsequent cursors.
**
** Return the number of indices on the table.
*/
int sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int baseCur,     /* Cursor number assigned to the table */
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  int iDb;
  Index *pIdx;
  Vdbe *v;

  if( IsVirtual(pTab) ) return 0;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, baseCur, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp4(v, op, i+baseCur, pIdx->tnum, iDb,
                      (char*)pKey, P4_KEYINFO_HANDOFF);
    VdbeComment((v, "%s", pIdx->zName));
  }
  if( pParse->nTab<baseCur+i ){
    pParse->nTab = baseCur+i;
  }
  return i-1;
}


#ifdef SQLITE_TEST
/*
** The following global variable is incremented whenever the
** transfer optimization is used.  This is used for testing
** purposes only - to make sure the transfer optimization really
** is happening when it is suppose to.
*/
int sqlite3_xferopt_count;
#endif /* SQLITE_TEST */


#ifndef SQLITE_OMIT_XFER_OPT
/*
** Check to collation names to see if they are compatible.
*/
static int xferCompatibleCollation(const char *z1, const char *z2){
  if( z1==0 ){
    return z2==0;
  }
  if( z2==0 ){
    return 0;
  }
  return sqlite3StrICmp(z1, z2)==0;
}


/*
** Check to see if index pSrc is compatible as a source of data
** for index pDest in an insert transfer optimization.  The rules
** for a compatible index:
**
**    *   The index is over the same set of columns
**    *   The same DESC and ASC markings occurs on all columns
**    *   The same onError processing (OE_Abort, OE_Ignore, etc)
**    *   The same collating sequence on each column
*/
static int xferCompatibleIndex(Index *pDest, Index *pSrc){
  int i;
  assert( pDest && pSrc );
  assert( pDest->pTable!=pSrc->pTable );
  if( pDest->nColumn!=pSrc->nColumn ){
    return 0;   /* Different number of columns */
  }
  if( pDest->onError!=pSrc->onError ){
    return 0;   /* Different conflict resolution strategies */
  }
  for(i=0; i<pSrc->nColumn; i++){
    if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
      return 0;   /* Different columns indexed */
    }
    if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
      return 0;   /* Different sort orders */
    }
    if( !xferCompatibleCollation(pSrc->azColl[i],pDest->azColl[i]) ){
      return 0;   /* Different collating sequences */
    }
  }

  /* If no test above fails then the indices must be compatible */
  return 1;
}

/*
** Attempt the transfer optimization on INSERTs of the form
**
**     INSERT INTO tab1 SELECT * FROM tab2;
**
** This optimization is only attempted if
**
**    (1)  tab1 and tab2 have identical schemas including all the
**         same indices and constraints
**
**    (2)  tab1 and tab2 are different tables
**
**    (3)  There must be no triggers on tab1
**
**    (4)  The result set of the SELECT statement is "*"
**
**    (5)  The SELECT statement has no WHERE, HAVING, ORDER BY, GROUP BY,
**         or LIMIT clause.
**
**    (6)  The SELECT statement is a simple (not a compound) select that
**         contains only tab2 in its FROM clause
**
** This method for implementing the INSERT transfers raw records from
** tab2 over to tab1.  The columns are not decoded.  Raw records from
** the indices of tab2 are transfered to tab1 as well.  In so doing,
** the resulting tab1 has much less fragmentation.
**
** This routine returns TRUE if the optimization is attempted.  If any
** of the conditions above fail so that the optimization should not
** be attempted, then this routine returns FALSE.
*/
static int xferOptimization(
  Parse *pParse,        /* Parser context */
  Table *pDest,         /* The table we are inserting into */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  int onError,          /* How to handle constraint errors */
  int iDbDest           /* The database of pDest */
){
  ExprList *pEList;                /* The result set of the SELECT */
  Table *pSrc;                     /* The table in the FROM clause of SELECT */
  Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
  struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
  int i;                           /* Loop counter */
  int iDbSrc;                      /* The database of pSrc */
  int iSrc, iDest;                 /* Cursors from source and destination */
  int addr1, addr2;                /* Loop addresses */
  int emptyDestTest;               /* Address of test for empty pDest */
  int emptySrcTest;                /* Address of test for empty pSrc */
  Vdbe *v;                         /* The VDBE we are building */
  KeyInfo *pKey;                   /* Key information for an index */
  int regAutoinc;                  /* Memory register used by AUTOINC */
  int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
  int regData, regRowid;           /* Registers holding data and rowid */

  if( pSelect==0 ){
    return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
  }
  if( sqlite3TriggerList(pParse, pDest) ){
    return 0;   /* tab1 must not have triggers */
  }
#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( pDest->tabFlags & TF_Virtual ){
    return 0;   /* tab1 must not be a virtual table */
  }
#endif
  if( onError==OE_Default ){
    onError = OE_Abort;
  }
  if( onError!=OE_Abort && onError!=OE_Rollback ){
    return 0;   /* Cannot do OR REPLACE or OR IGNORE or OR FAIL */
  }
  assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
  if( pSelect->pSrc->nSrc!=1 ){
    return 0;   /* FROM clause must have exactly one term */
  }
  if( pSelect->pSrc->a[0].pSelect ){
    return 0;   /* FROM clause cannot contain a subquery */
  }
  if( pSelect->pWhere ){
    return 0;   /* SELECT may not have a WHERE clause */
  }
  if( pSelect->pOrderBy ){
    return 0;   /* SELECT may not have an ORDER BY clause */
  }
  /* Do not need to test for a HAVING clause.  If HAVING is present but
  ** there is no ORDER BY, we will get an error. */
  if( pSelect->pGroupBy ){
    return 0;   /* SELECT may not have a GROUP BY clause */
  }
  if( pSelect->pLimit ){
    return 0;   /* SELECT may not have a LIMIT clause */
  }
  assert( pSelect->pOffset==0 );  /* Must be so if pLimit==0 */
  if( pSelect->pPrior ){
    return 0;   /* SELECT may not be a compound query */
  }
  if( pSelect->selFlags & SF_Distinct ){
    return 0;   /* SELECT may not be DISTINCT */
  }
  pEList = pSelect->pEList;
  assert( pEList!=0 );
  if( pEList->nExpr!=1 ){
    return 0;   /* The result set must have exactly one column */
  }
  assert( pEList->a[0].pExpr );
  if( pEList->a[0].pExpr->op!=TK_ALL ){
    return 0;   /* The result set must be the special operator "*" */
  }

  /* At this point we have established that the statement is of the
  ** correct syntactic form to participate in this optimization.  Now
  ** we have to check the semantics.
  */
  pItem = pSelect->pSrc->a;
  pSrc = sqlite3LocateTable(pParse, 0, pItem->zName, pItem->zDatabase);
  if( pSrc==0 ){
    return 0;   /* FROM clause does not contain a real table */
  }
  if( pSrc==pDest ){
    return 0;   /* tab1 and tab2 may not be the same table */
  }
#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( pSrc->tabFlags & TF_Virtual ){
    return 0;   /* tab2 must not be a virtual table */
  }
#endif
  if( pSrc->pSelect ){
    return 0;   /* tab2 may not be a view */
  }
  if( pDest->nCol!=pSrc->nCol ){
    return 0;   /* Number of columns must be the same in tab1 and tab2 */
  }
  if( pDest->iPKey!=pSrc->iPKey ){
    return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
  }
  for(i=0; i<pDest->nCol; i++){
    if( pDest->aCol[i].affinity!=pSrc->aCol[i].affinity ){
      return 0;    /* Affinity must be the same on all columns */
    }
    if( !xferCompatibleCollation(pDest->aCol[i].zColl, pSrc->aCol[i].zColl) ){
      return 0;    /* Collating sequence must be the same on all columns */
    }
    if( pDest->aCol[i].notNull && !pSrc->aCol[i].notNull ){
      return 0;    /* tab2 must be NOT NULL if tab1 is */
    }
  }
  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
    if( pDestIdx->onError!=OE_None ){
      destHasUniqueIdx = 1;
    }
    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
    }
    if( pSrcIdx==0 ){
      return 0;    /* pDestIdx has no corresponding index in pSrc */
    }
  }
#ifndef SQLITE_OMIT_CHECK
  if( pDest->pCheck && !sqlite3ExprCompare(pSrc->pCheck, pDest->pCheck) ){
    return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
  }
#endif

  /* If we get this far, it means either:
  **
  **    *   We can always do the transfer if the table contains an
  **        an integer primary key
  **
  **    *   We can conditionally do the transfer if the destination
  **        table is empty.
  */
#ifdef SQLITE_TEST
  sqlite3_xferopt_count++;
#endif
  iDbSrc = sqlite3SchemaToIndex(pParse->db, pSrc->pSchema);
  v = sqlite3GetVdbe(pParse);
  sqlite3CodeVerifySchema(pParse, iDbSrc);
  iSrc = pParse->nTab++;
  iDest = pParse->nTab++;
  regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
  sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
  if( (pDest->iPKey<0 && pDest->pIndex!=0) || destHasUniqueIdx ){
    /* If tables do not have an INTEGER PRIMARY KEY and there
    ** are indices to be copied and the destination is not empty,
    ** we have to disallow the transfer optimization because the
    ** the rowids might change which will mess up indexing.
    **
    ** Or if the destination has a UNIQUE index and is not empty,
    ** we also disallow the transfer optimization because we cannot
    ** insure that all entries in the union of DEST and SRC will be
    ** unique.
    */
    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0);
    emptyDestTest = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
  }else{
    emptyDestTest = 0;
  }
  sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
  emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0);
  regData = sqlite3GetTempReg(pParse);
  regRowid = sqlite3GetTempReg(pParse);
  if( pDest->iPKey>=0 ){
    addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
    addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
    sqlite3HaltConstraint(
        pParse, onError, "PRIMARY KEY must be unique", P4_STATIC);
    sqlite3VdbeJumpHere(v, addr2);
    autoIncStep(pParse, regAutoinc, regRowid);
  }else if( pDest->pIndex==0 ){
    addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
  }else{
    addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
    assert( (pDest->tabFlags & TF_Autoincrement)==0 );
  }
  sqlite3VdbeAddOp2(v, OP_RowData, iSrc, regData);
  sqlite3VdbeAddOp3(v, OP_Insert, iDest, regData, regRowid);
  sqlite3VdbeChangeP5(v, OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND);
  sqlite3VdbeChangeP4(v, -1, pDest->zName, 0);
  sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1);
  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
    for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
    }
    assert( pSrcIdx );
    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
    pKey = sqlite3IndexKeyinfo(pParse, pSrcIdx);
    sqlite3VdbeAddOp4(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc,
                      (char*)pKey, P4_KEYINFO_HANDOFF);
    VdbeComment((v, "%s", pSrcIdx->zName));
    pKey = sqlite3IndexKeyinfo(pParse, pDestIdx);
    sqlite3VdbeAddOp4(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest,
                      (char*)pKey, P4_KEYINFO_HANDOFF);
    VdbeComment((v, "%s", pDestIdx->zName));
    addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0);
    sqlite3VdbeAddOp2(v, OP_RowKey, iSrc, regData);
    sqlite3VdbeAddOp3(v, OP_IdxInsert, iDest, regData, 1);
    sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1);
    sqlite3VdbeJumpHere(v, addr1);
  }
  sqlite3VdbeJumpHere(v, emptySrcTest);
  sqlite3ReleaseTempReg(pParse, regRowid);
  sqlite3ReleaseTempReg(pParse, regData);
  sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
  sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  if( emptyDestTest ){
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
    sqlite3VdbeJumpHere(v, emptyDestTest);
    sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
    return 0;
  }else{
    return 1;
  }
}
#endif /* SQLITE_OMIT_XFER_OPT */

/* Make sure "isView" gets undefined in case this file becomes part of
** the amalgamation - so that subsequent files do not see isView as a
** macro. */
#undef isView

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