SQLite

    puts $lot2
    error "databases contain different tables" 
  }

  foreach tbl $lot1 {
    set col1 [list]
    set col2 [list]
    set quoted [list]

    $db1 eval "PRAGMA table_info = $tbl" { lappend col1 $name }
    $db2 eval "PRAGMA table_info = $tbl" { 
      lappend col2 $name 
      lappend quoted "\"[string map {\" \"\"} $name]\""
    }
    if {$col1 != $col2} { error "table $tbl schema mismatch" }

    set sql "SELECT * FROM $tbl ORDER BY [join $quoted ,]"
    set data1 [$db1 eval $sql]
    set data2 [$db2 eval $sql]
    if {$data1 != $data2} { 
      puts "$db1: $data1"
      puts "$db2: $data2"
      error "table $tbl data mismatch" 
    }

# 2025 Jan 28
#
# 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 implements regression tests for SQLite library.
#

if {![info exists testdir]} {
  set testdir [file join [file dirname [info script]] .. .. test]
} 
source [file join [file dirname [info script]] session_common.tcl]
source $testdir/tester.tcl
ifcapable !session {finish_test; return}

set testprefix session_gen


foreach {otn sct} {
  1  VIRTUAL
  2  STORED
} {
eval [string map [list %TYPE% $sct] {
  reset_db
  set testprefix $testprefix-$otn

do_execsql_test 1.0 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);

  CREATE TABLE t2(a INTEGER PRIMARY KEY, b AS (c+1) %TYPE%, c);

  CREATE TABLE t3(
    a, 
    b AS (a+10) %TYPE%, 
    c, 
    d AS (c+1) %TYPE%, 
    e, 
    PRIMARY KEY(c, e)
  ) WITHOUT ROWID;

  CREATE TABLE t4(a AS (c*100) %TYPE%, b INTEGER PRIMARY KEY, c);

  CREATE TABLE t5(x, y);
}

foreach {tn sql changeset} {
  
  0.1 {
    INSERT INTO t5 VALUES('abc', 'def');
  } {
    {INSERT t5 0 X.. {} {i 1 t abc t def}}
  }
  0.2 {
    UPDATE t5 SET y='xyz' WHERE rowid=1;
  } {
    {UPDATE t5 0 X.. {i 1 {} {} t def} {{} {} {} {} t xyz}}
  }
  0.3 {
    DELETE FROM t5;
  } {
    {DELETE t5 0 X.. {i 1 t abc t xyz} {}}
  }

  1.1 {
    INSERT INTO t2 VALUES(1, 2);
    INSERT INTO t2 VALUES(2, 123);
  } {
    {INSERT t2 0 X. {} {i 1 i 2}}
    {INSERT t2 0 X. {} {i 2 i 123}}
  }
  1.2 {
    UPDATE t2 SET c=456 WHERE a=1
  } {
    {UPDATE t2 0 X. {i 1 i 2} {{} {} i 456}}
  }

  1.3 {
    DELETE FROM t2 WHERE a=2
  } {
    {DELETE t2 0 X. {i 2 i 123} {}}
  }

  1.4 {
    UPDATE t2 SET a=15
  } {
    {INSERT t2 0 X. {} {i 15 i 456}} 
    {DELETE t2 0 X. {i 1 i 456} {}}
  }

  2.1 {
    INSERT INTO t3 VALUES(5, 6, 7);
    INSERT INTO t3 VALUES(8, 9, 10);
  } {
    {INSERT t3 0 .XX {} {i 8 i 9 i 10}}
    {INSERT t3 0 .XX {} {i 5 i 6 i 7}}
  }

  2.2 {
    UPDATE t3 SET a = 505 WHERE (c, e) = (6, 7);
  } {
    {UPDATE t3 0 .XX {i 5 i 6 i 7} {i 505 {} {} {} {}}}
  }

  2.3 {
    DELETE FROM t3 WHERE (c, e) = (9, 10);
  } {
    {DELETE t3 0 .XX {i 8 i 9 i 10} {}}
  }

  2.4 {
    UPDATE t3 SET c=1000
  } {
    {DELETE t3 0 .XX {i 505 i 6 i 7} {}}
    {INSERT t3 0 .XX {} {i 505 i 1000 i 7}}
  }

  3.1 {
    INSERT INTO t4 VALUES(100, 100);
  } {
    {INSERT t4 0 X. {} {i 100 i 100}}
  }

} {
  do_test 1.$tn.1 {
    sqlite3session S db main
  S object_config rowid 1
    S attach *
    execsql $sql
  } {}

  do_changeset_test 1.$tn.2 S $changeset

  S delete
}
#-------------------------------------------------------------------------
reset_db

forcedelete test.db2
sqlite3 db2 test.db2

do_common_sql {
  CREATE TABLE t0(x INTEGER PRIMARY KEY, y);
  INSERT INTO t0 VALUES(1, 'one');
  INSERT INTO t0 VALUES(2, 'two');

  CREATE TABLE t1(a AS (c*10) %TYPE%, b INTEGER PRIMARY KEY, c);
  INSERT INTO t1 VALUES(1, 5);
  INSERT INTO t1 VALUES(2, 10);
  INSERT INTO t1 VALUES(3, 5);

  CREATE TABLE t2(
    a, b, c AS (a*b) %TYPE%,
    'k 1', 'k 2', PRIMARY KEY('k 1', 'k 2')
  ) WITHOUT ROWID;
  INSERT INTO t2 VALUES('a', 'b', 1, 11);
  INSERT INTO t2 VALUES('A', 'B', 2, 22);
  INSERT INTO t2 VALUES('Aa', 'Bb', 3, 33);
}

foreach {tn sql} {
  1.1 { INSERT INTO t0 VALUES(4, 15) }
  1.2 { INSERT INTO t1 VALUES(4, 15) }
  1.3 { INSERT INTO t2 VALUES(1, 2, 3, 4) }

  2.1 { UPDATE t1 SET c=100 WHERE b=2 }
  2.2 { UPDATE t2 SET a=11 }

  3.1 { DELETE FROM t2 WHERE (t2.'k 1') = 2 }
  3.2 { DELETE FROM t1 }
} {
  do_test 2.$tn.1 {
  # execsql { PRAGMA vdbe_listing = 1 } db2
    do_then_apply_sql $sql
  } {}
  do_test 2.$tn.2 {
    compare_db db db2
  } {}
}

}]}




finish_test

**   then this variable is the compiled version of:
**
**      SELECT 1, NULL, 'abc'
*/
struct SessionTable {
  SessionTable *pNext;
  char *zName;                    /* Local name of table */
  int nCol;                       /* Number of non-hidden columns */
  int nTotalCol;                  /* Number of columns including hidden */
  int bStat1;                     /* True if this is sqlite_stat1 */
  int bRowid;                     /* True if this table uses rowid for PK */
  const char **azCol;             /* Column names */
  const char **azDflt;            /* Default value expressions */
  int *aiIdx;                     /* Index to pass to xNew/xOld */
  u8 *abPK;                       /* Array of primary key flags */
  int nEntry;                     /* Total number of entries in hash table */
  int nChange;                    /* Size of apChange[] array */
  SessionChange **apChange;       /* Hash table buckets */
  sqlite3_stmt *pDfltStmt;
};

  int bNew,                       /* True to hash the new.* PK */
  int *piHash,                    /* OUT: Hash value */
  int *pbNullPK                   /* OUT: True if there are NULL values in PK */
){
  unsigned int h = 0;             /* Hash value to return */
  int i;                          /* Used to iterate through columns */

  assert( pTab->nTotalCol==pSession->hook.xCount(pSession->hook.pCtx) );
  if( pTab->bRowid ){

    h = sessionHashAppendI64(h, iRowid);
  }else{
    assert( *pbNullPK==0 );

    for(i=0; i<pTab->nCol; i++){
      if( pTab->abPK[i] ){
        int rc;
        int eType;
        sqlite3_value *pVal;
        int iIdx = pTab->aiIdx[i];

        if( bNew ){
          rc = pSession->hook.xNew(pSession->hook.pCtx, iIdx, &pVal);
        }else{
          rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &pVal);
        }
        if( rc!=SQLITE_OK ) return rc;

        eType = sqlite3_value_type(pVal);
        h = sessionHashAppendType(h, eType);
        if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
          i64 iVal;

  for(iCol=0; iCol<pTab->nCol; iCol++){
    if( !pTab->abPK[iCol] ){
      a += sessionSerialLen(a);
    }else{
      sqlite3_value *pVal;        /* Value returned by preupdate_new/old */
      int rc;                     /* Error code from preupdate_new/old */
      int eType = *a++;           /* Type of value from change record */
      int iIdx = pTab->aiIdx[iCol];

      /* The following calls to preupdate_new() and preupdate_old() can not
      ** fail. This is because they cache their return values, and by the
      ** time control flows to here they have already been called once from
      ** within sessionPreupdateHash(). The first two asserts below verify
      ** this (that the method has already been called). */
      if( op==SQLITE_INSERT ){
        /* assert( db->pPreUpdate->pNewUnpacked || db->pPreUpdate->aNew ); */
        rc = pSession->hook.xNew(pSession->hook.pCtx, iIdx, &pVal);
      }else{
        /* assert( db->pPreUpdate->pUnpacked ); */
        rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &pVal);
      }
      assert( rc==SQLITE_OK );
      (void)rc;                   /* Suppress warning about unused variable */
      if( sqlite3_value_type(pVal)!=eType ) return 0;

      /* A SessionChange object never has a NULL value in a PK column */
      assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT

*/
static int sessionTableInfo(
  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
  sqlite3 *db,                    /* Database connection */
  const char *zDb,                /* Name of attached database (e.g. "main") */
  const char *zThis,              /* Table name */
  int *pnCol,                     /* OUT: number of columns */
  int *pnTotalCol,                /* OUT: number of hidden columns */
  const char **pzTab,             /* OUT: Copy of zThis */
  const char ***pazCol,           /* OUT: Array of column names for table */
  const char ***pazDflt,          /* OUT: Array of default value expressions */
  int **paiIdx,                   /* OUT: Array of xNew/xOld indexes */
  u8 **pabPK,                     /* OUT: Array of booleans - true for PK col */
  int *pbRowid                    /* OUT: True if only PK is a rowid */
){
  char *zPragma;
  sqlite3_stmt *pStmt;
  int rc;
  sqlite3_int64 nByte;
  int nDbCol = 0;
  int nThis;
  int i;
  u8 *pAlloc = 0;
  char **azCol = 0;
  char **azDflt = 0;
  u8 *abPK = 0;
  int *aiIdx = 0;
  int bRowid = 0;                 /* Set to true to use rowid as PK */

  assert( pazCol && pabPK );

  *pazCol = 0;
  *pabPK = 0;
  *pnCol = 0;
  if( pnTotalCol ) *pnTotalCol = 0;
  if( paiIdx ) *paiIdx = 0;
  if( pzTab ) *pzTab = 0;
  if( pazDflt ) *pazDflt = 0;

  nThis = sqlite3Strlen30(zThis);
  if( nThis==12 && 0==sqlite3_stricmp("sqlite_stat1", zThis) ){
    rc = sqlite3_table_column_metadata(db, zDb, zThis, 0, 0, 0, 0, 0, 0);
    if( rc==SQLITE_OK ){
      /* For sqlite_stat1, pretend that (tbl,idx) is the PRIMARY KEY. */
      zPragma = sqlite3_mprintf(
          "SELECT 0, 'tbl',  '', 0, '', 1, 0     UNION ALL "
          "SELECT 1, 'idx',  '', 0, '', 2, 0     UNION ALL "
          "SELECT 2, 'stat', '', 0, '', 0, 0"
      );
    }else if( rc==SQLITE_ERROR ){
      zPragma = sqlite3_mprintf("");
    }else{
      return rc;
    }
  }else{
    zPragma = sqlite3_mprintf("PRAGMA '%q'.table_xinfo('%q')", zDb, zThis);
  }
  if( !zPragma ){
    return SQLITE_NOMEM;
  }

  rc = sqlite3_prepare_v2(db, zPragma, -1, &pStmt, 0);
  sqlite3_free(zPragma);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  nByte = nThis + 1;
  bRowid = (pbRowid!=0);
  while( SQLITE_ROW==sqlite3_step(pStmt) ){
    nByte += sqlite3_column_bytes(pStmt, 1);          /* name */
    nByte += sqlite3_column_bytes(pStmt, 4);          /* dflt_value */
    if( sqlite3_column_int(pStmt, 6)==0 ){            /* !hidden */
      nDbCol++;
    }
    if( sqlite3_column_int(pStmt, 5) ) bRowid = 0;    /* pk */
  }
  if( nDbCol==0 ) bRowid = 0;
  nDbCol += bRowid;
  nByte += strlen(SESSIONS_ROWID);
  rc = sqlite3_reset(pStmt);

  if( rc==SQLITE_OK ){
    nByte += nDbCol * (sizeof(const char *)*2 +sizeof(int)+sizeof(u8) + 1 + 1);
    pAlloc = sessionMalloc64(pSession, nByte);
    if( pAlloc==0 ){
      rc = SQLITE_NOMEM;
    }else{
      memset(pAlloc, 0, nByte);
    }
  }
  if( rc==SQLITE_OK ){
    azCol = (char **)pAlloc;
    azDflt = (char**)&azCol[nDbCol];
    aiIdx = (int*)&azDflt[nDbCol];
    abPK = (u8 *)&aiIdx[nDbCol];
    pAlloc = &abPK[nDbCol];
    if( pzTab ){
      memcpy(pAlloc, zThis, nThis+1);
      *pzTab = (char *)pAlloc;
      pAlloc += nThis+1;
    }
  
    i = 0;
    if( bRowid ){
      size_t nName = strlen(SESSIONS_ROWID);
      memcpy(pAlloc, SESSIONS_ROWID, nName+1);
      azCol[i] = (char*)pAlloc;
      pAlloc += nName+1;
      abPK[i] = 1;
      aiIdx[i] = -1;
      i++;
    }
    while( SQLITE_ROW==sqlite3_step(pStmt) ){
      if( sqlite3_column_int(pStmt, 6)==0 ){            /* !hidden */
        int nName = sqlite3_column_bytes(pStmt, 1);
        int nDflt = sqlite3_column_bytes(pStmt, 4);
        const unsigned char *zName = sqlite3_column_text(pStmt, 1);
        const unsigned char *zDflt = sqlite3_column_text(pStmt, 4);

        if( zName==0 ) break;
        memcpy(pAlloc, zName, nName+1);
        azCol[i] = (char *)pAlloc;
        pAlloc += nName+1;
        if( zDflt ){
          memcpy(pAlloc, zDflt, nDflt+1);
          azDflt[i] = (char *)pAlloc;
          pAlloc += nDflt+1;
        }else{
          azDflt[i] = 0;
        }
        abPK[i] = sqlite3_column_int(pStmt, 5);
        aiIdx[i] = sqlite3_column_int(pStmt, 0);
        i++;
      }
      if( pnTotalCol ) (*pnTotalCol)++;
    }
    rc = sqlite3_reset(pStmt);
  }

  /* If successful, populate the output variables. Otherwise, zero them and
  ** free any allocation made. An error code will be returned in this case.
  */
  if( rc==SQLITE_OK ){
    *pazCol = (const char**)azCol;
    if( pazDflt ) *pazDflt = (const char**)azDflt;
    *pabPK = abPK;
    *pnCol = nDbCol;
    if( paiIdx ) *paiIdx = aiIdx;
  }else{
    sessionFree(pSession, azCol);
  }
  if( pbRowid ) *pbRowid = bRowid;
  sqlite3_finalize(pStmt);
  return rc;
}

){
  int rc = SQLITE_OK;

  if( pTab->nCol==0 ){
    u8 *abPK;
    assert( pTab->azCol==0 || pTab->abPK==0 );
    rc = sessionTableInfo(pSession, db, zDb, 
        pTab->zName, &pTab->nCol, &pTab->nTotalCol, 0, &pTab->azCol, 
        &pTab->azDflt, &pTab->aiIdx, &abPK,
        ((pSession==0 || pSession->bImplicitPK) ? &pTab->bRowid : 0)
    );
    if( rc==SQLITE_OK ){
      int i;
      for(i=0; i<pTab->nCol; i++){
        if( abPK[i] ){
          pTab->abPK = abPK;

}

/*
** Re-initialize table object pTab.
*/
static int sessionReinitTable(sqlite3_session *pSession, SessionTable *pTab){
  int nCol = 0;
  int nTotalCol = 0;
  const char **azCol = 0;
  const char **azDflt = 0;
  int *aiIdx = 0;
  u8 *abPK = 0; 
  int bRowid = 0;

  assert( pSession->rc==SQLITE_OK );

  pSession->rc = sessionTableInfo(pSession, pSession->db, pSession->zDb, 
      pTab->zName, &nCol, &nTotalCol, 0, &azCol, &azDflt, &aiIdx, &abPK,
      (pSession->bImplicitPK ? &bRowid : 0)
  );
  if( pSession->rc==SQLITE_OK ){
    if( pTab->nCol>nCol || pTab->bRowid!=bRowid ){
      pSession->rc = SQLITE_SCHEMA;
    }else{
      int ii;

        }
      }

      if( pSession->rc==SQLITE_OK ){
        const char **a = pTab->azCol;
        pTab->azCol = azCol;
        pTab->nCol = nCol;
        pTab->nTotalCol = nTotalCol;
        pTab->azDflt = azDflt;
        pTab->abPK = abPK;
        pTab->aiIdx = aiIdx;
        azCol = a;
      }
      if( pSession->bEnableSize ){
        pSession->nMaxChangesetSize += (nCol - nOldCol);
        pSession->nMaxChangesetSize += sessionVarintLen(nCol);
        pSession->nMaxChangesetSize -= sessionVarintLen(nOldCol);
      }

  i64 nNew = 2;
  if( pC->op==SQLITE_INSERT ){
    if( pTab->bRowid ) nNew += 9;
    if( op!=SQLITE_DELETE ){
      int ii;
      for(ii=0; ii<pTab->nCol; ii++){
        sqlite3_value *p = 0;
        pSession->hook.xNew(pSession->hook.pCtx, pTab->aiIdx[ii], &p);
        sessionSerializeValue(0, p, &nNew);
      }
    }
  }else if( op==SQLITE_DELETE ){
    nNew += pC->nRecord;
    if( sqlite3_preupdate_blobwrite(pSession->db)>=0 ){
      nNew += pC->nRecord;
    }
  }else{
    int ii;
    u8 *pCsr = pC->aRecord;
    if( pTab->bRowid ){
      nNew += 9 + 1;
      pCsr += 9;
    }
    for(ii=pTab->bRowid; ii<pTab->nCol; ii++){
      int bChanged = 1;
      int nOld = 0;
      int eType;
      int iIdx = pTab->aiIdx[ii];
      sqlite3_value *p = 0;
      pSession->hook.xNew(pSession->hook.pCtx, iIdx, &p);
      if( p==0 ){
        return SQLITE_NOMEM;
      }

      eType = *pCsr++;
      switch( eType ){
        case SQLITE_NULL:

  /* Load table details if required */
  if( sessionInitTable(pSession, pTab, pSession->db, pSession->zDb) ) return;

  /* Check the number of columns in this xPreUpdate call matches the 
  ** number of columns in the table.  */
  nExpect = pSession->hook.xCount(pSession->hook.pCtx);
  if( pTab->nTotalCol<nExpect ){
    if( sessionReinitTable(pSession, pTab) ) return;
    if( sessionUpdateChanges(pSession, pTab) ) return;
  }
  if( pTab->nTotalCol!=nExpect ){
    pSession->rc = SQLITE_SCHEMA;
    return;
  }

  /* Grow the hash table if required */
  if( sessionGrowHash(pSession, 0, pTab) ){
    pSession->rc = SQLITE_NOMEM;

      int i;                  /* Used to iterate through columns */
  
      assert( rc==SQLITE_OK );
      pTab->nEntry++;
  
      /* Figure out how large an allocation is required */
      nByte = sizeof(SessionChange);
      for(i=pTab->bRowid; i<pTab->nCol; i++){
        int iIdx = pTab->aiIdx[i];
        sqlite3_value *p = 0;
        if( op!=SQLITE_INSERT ){
          /* This may fail if the column has a non-NULL default and was added 
          ** using ALTER TABLE ADD COLUMN after this record was created. */
          rc = pSession->hook.xOld(pSession->hook.pCtx, iIdx, &p);
        }else if( pTab->abPK[i] ){
          TESTONLY(int trc = ) pSession->hook.xNew(pSession->hook.pCtx,iIdx,&p);
          assert( trc==SQLITE_OK );
        }

        if( rc==SQLITE_OK ){
          /* This may fail if SQLite value p contains a utf-16 string that must
          ** be converted to utf-8 and an OOM error occurs while doing so. */
          rc = sessionSerializeValue(0, p, &nByte);

      ** It is not possible for an OOM to occur in this block. */
      nByte = 0;
      if( pTab->bRowid ){
        pC->aRecord[0] = SQLITE_INTEGER;
        sessionPutI64(&pC->aRecord[1], iRowid);
        nByte = 9;
      }
      for(i=pTab->bRowid; i<pTab->nCol; i++){
        sqlite3_value *p = 0;
        int iIdx = pTab->aiIdx[i];
        if( op!=SQLITE_INSERT ){
          pSession->hook.xOld(pSession->hook.pCtx, iIdx, &p);
        }else if( pTab->abPK[i] ){
          pSession->hook.xNew(pSession->hook.pCtx, iIdx, &p);
        }
        sessionSerializeValue(&pC->aRecord[nByte], p, &nByte);
      }

      /* Add the change to the hash-table */
      if( pSession->bIndirect || pSession->hook.xDepth(pSession->hook.pCtx) ){
        pC->bIndirect = 1;

    if( rc==SQLITE_OK ){
      int bHasPk = 0;
      int bMismatch = 0;
      int nCol;                   /* Columns in zFrom.zTbl */
      int bRowid = 0;
      u8 *abPK;
      const char **azCol = 0;
      rc = sessionTableInfo(0, db, zFrom, zTbl, 
          &nCol, 0, 0, &azCol, 0, 0, &abPK, 
          pSession->bImplicitPK ? &bRowid : 0
      );
      if( rc==SQLITE_OK ){
        if( pTo->nCol!=nCol ){
          bMismatch = 1;
        }else{
          int i;

  const char **azCol,             /* Names of table columns */
  u8 *abPK,                       /* PRIMARY KEY  array */
  sqlite3_stmt **ppStmt           /* OUT: Prepared SELECT statement */
){
  int rc = SQLITE_OK;
  char *zSql = 0;
  const char *zSep = "";

  int nSql = -1;
  int i;

  SessionBuffer cols = {0, 0, 0};
  SessionBuffer nooptest = {0, 0, 0};
  SessionBuffer pkfield = {0, 0, 0};
  SessionBuffer pkvar = {0, 0, 0};

  sessionAppendStr(&nooptest, ", 1", &rc);

  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
    sessionAppendStr(&nooptest, " AND (?6 OR ?3 IS stat)", &rc);
    sessionAppendStr(&pkfield, "tbl, idx", &rc);
    sessionAppendStr(&pkvar, 
        "?1, (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", &rc
    );
    sessionAppendStr(&cols, "tbl, ?2, stat", &rc);
  }else{
  #if 0
    if( bRowid ){
      sessionAppendStr(&cols, SESSIONS_ROWID, &rc);
    }
    #endif
    for(i=0; i<nCol; i++){
      if( cols.nBuf ) sessionAppendStr(&cols, ", ", &rc);
      sessionAppendIdent(&cols, azCol[i], &rc);
      if( abPK[i] ){
        sessionAppendStr(&pkfield, zSep, &rc);
        sessionAppendStr(&pkvar, zSep, &rc);
        zSep = ", ";
        sessionAppendIdent(&pkfield, azCol[i], &rc);
        sessionAppendPrintf(&pkvar, &rc, "?%d", i+1);
      }else{
        sessionAppendPrintf(&nooptest, &rc, 
            " AND (?%d OR ?%d IS %w.%w)", i+1+nCol, i+1, zTab, azCol[i]
        );
      }
    }
  }

  if( rc==SQLITE_OK ){
    zSql = sqlite3_mprintf(
        "SELECT %s%s FROM %Q.%Q WHERE (%s) IS (%s)",
        (char*)cols.aBuf, (bIgnoreNoop ? (char*)nooptest.aBuf : ""), 
        zDb, zTab, (char*)pkfield.aBuf, (char*)pkvar.aBuf
    );
    if( zSql==0 ) rc = SQLITE_NOMEM;
  }

#if 0
  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){

  if( rc==SQLITE_OK ){
    rc = sqlite3_prepare_v2(db, zSql, nSql, ppStmt, 0);
  }
  sqlite3_free(zSql);
  sqlite3_free(nooptest.aBuf);
  sqlite3_free(pkfield.aBuf);
  sqlite3_free(pkvar.aBuf);
  sqlite3_free(cols.aBuf);
  return rc;
}

/*
** Bind the PRIMARY KEY values from the change passed in argument pChange
** to the SELECT statement passed as the first argument. The SELECT statement
** is as prepared by function sessionSelectStmt().

        sApply.azCol = (const char **)zTab;
      }else{
        int nMinCol = 0;
        int i;

        sqlite3changeset_pk(pIter, &abPK, 0);
        rc = sessionTableInfo(0, db, "main", zNew, 
            &sApply.nCol, 0, &zTab, &sApply.azCol, 0, 0, 
            &sApply.abPK, &sApply.bRowid
        );
        if( rc!=SQLITE_OK ) break;
        for(i=0; i<sApply.nCol; i++){
          if( sApply.abPK[i] ) nMinCol = i+1;
        }
  
        if( sApply.nCol==0 ){

** This function is called from within a pre-update callback to retrieve
** a field of the row currently being updated or deleted.
*/
int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
  PreUpdate *p;
  Mem *pMem;
  int rc = SQLITE_OK;
  int iStore = 0;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( db==0 || ppValue==0 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  p = db->pPreUpdate;
  /* Test that this call is being made from within an SQLITE_DELETE or
  ** SQLITE_UPDATE pre-update callback, and that iIdx is within range. */
  if( !p || p->op==SQLITE_INSERT ){
    rc = SQLITE_MISUSE_BKPT;
    goto preupdate_old_out;
  }
  if( p->pPk ){
    iStore = sqlite3TableColumnToIndex(p->pPk, iIdx);
  }else{
    iStore = sqlite3TableColumnToStorage(p->pTab, iIdx);
  }
  if( iStore>=p->pCsr->nField || iStore<0 ){
    rc = SQLITE_RANGE;
    goto preupdate_old_out;
  }

  if( iIdx==p->pTab->iPKey ){
    *ppValue = pMem = &p->oldipk;
    sqlite3VdbeMemSetInt64(pMem, p->iKey1);

      if( rc!=SQLITE_OK ){
        sqlite3DbFree(db, aRec);
        goto preupdate_old_out;
      }
      p->aRecord = aRec;
    }

    pMem = *ppValue = &p->pUnpacked->aMem[iStore];
    if( iStore>=p->pUnpacked->nField ){
      /* This occurs when the table has been extended using ALTER TABLE
      ** ADD COLUMN. The value to return is the default value of the column. */
      Column *pCol = &p->pTab->aCol[iIdx];
      if( pCol->iDflt>0 ){
        if( p->apDflt==0 ){
          int nByte = sizeof(sqlite3_value*)*p->pTab->nCol;
          p->apDflt = (sqlite3_value**)sqlite3DbMallocZero(db, nByte);

** This function is called from within a pre-update callback to retrieve
** a field of the row currently being updated or inserted.
*/
int sqlite3_preupdate_new(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
  PreUpdate *p;
  int rc = SQLITE_OK;
  Mem *pMem;
  int iStore = 0;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( db==0 || ppValue==0 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  p = db->pPreUpdate;
  if( !p || p->op==SQLITE_DELETE ){
    rc = SQLITE_MISUSE_BKPT;
    goto preupdate_new_out;
  }
  if( p->pPk && p->op!=SQLITE_UPDATE ){
    iStore = sqlite3TableColumnToIndex(p->pPk, iIdx);
  }else{
    iStore = sqlite3TableColumnToStorage(p->pTab, iIdx);
  }

  if( iStore>=p->pCsr->nField || iStore<0 ){
    rc = SQLITE_RANGE;
    goto preupdate_new_out;
  }

  if( p->op==SQLITE_INSERT ){
    /* For an INSERT, memory cell p->iNewReg contains the serialized record
    ** that is being inserted. Deserialize it. */
    UnpackedRecord *pUnpack = p->pNewUnpacked;
    if( !pUnpack ){
      Mem *pData = &p->v->aMem[p->iNewReg];
      rc = ExpandBlob(pData);
      if( rc!=SQLITE_OK ) goto preupdate_new_out;
      pUnpack = vdbeUnpackRecord(&p->keyinfo, pData->n, pData->z);
      if( !pUnpack ){
        rc = SQLITE_NOMEM;
        goto preupdate_new_out;
      }
      p->pNewUnpacked = pUnpack;
    }
    pMem = &pUnpack->aMem[iStore];
    if( iIdx==p->pTab->iPKey ){
      sqlite3VdbeMemSetInt64(pMem, p->iKey2);
    }else if( iStore>=pUnpack->nField ){
      pMem = (sqlite3_value *)columnNullValue();
    }
  }else{
    /* For an UPDATE, memory cell (p->iNewReg+1+iStore) contains the required
    ** value. Make a copy of the cell contents and return a pointer to it.
    ** It is not safe to return a pointer to the memory cell itself as the
    ** caller may modify the value text encoding.
    */
    assert( p->op==SQLITE_UPDATE );
    if( !p->aNew ){
      p->aNew = (Mem *)sqlite3DbMallocZero(db, sizeof(Mem) * p->pCsr->nField);
      if( !p->aNew ){
        rc = SQLITE_NOMEM;
        goto preupdate_new_out;
      }
    }
    assert( iStore>=0 && iStore<p->pCsr->nField );
    pMem = &p->aNew[iStore];
    if( pMem->flags==0 ){
      if( iIdx==p->pTab->iPKey ){
        sqlite3VdbeMemSetInt64(pMem, p->iKey2);
      }else{
        rc = sqlite3VdbeMemCopy(pMem, &p->v->aMem[p->iNewReg+1+iStore]);
        if( rc!=SQLITE_OK ) goto preupdate_new_out;
      }
    }
  }
  *ppValue = pMem;

 preupdate_new_out: