insert.c

嵌入式数据系统软件！

** arguments to sqlite3GenerateConstraintChecks.
*/
void sqlite3CompleteInsertion(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int base,           /* Index of a read/write cursor pointing at pTab */
  char *aIdxUsed,     /* Which indices are used.  NULL means all are used */
  int rowidChng,      /* True if the record number will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int newIdx,         /* Index of NEW table for triggers.  -1 if none */
  int appendBias      /* True if this is likely to be an append */
){
  int i;
  Vdbe *v;
  int nIdx;
  Index *pIdx;
  int pik_flags;

  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( aIdxUsed && aIdxUsed[i]==0 ) continue;
    sqlite3VdbeAddOp(v, OP_IdxInsert, base+i+1, 0);
  }
  sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
  sqlite3TableAffinityStr(v, pTab);
#ifndef SQLITE_OMIT_TRIGGER
  if( newIdx>=0 ){
    sqlite3VdbeAddOp(v, OP_Dup, 1, 0);
    sqlite3VdbeAddOp(v, OP_Dup, 1, 0);
    sqlite3VdbeAddOp(v, OP_Insert, newIdx, 0);
  }
#endif
  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
  }
  if( appendBias ){
    pik_flags |= OPFLAG_APPEND;
  }
  sqlite3VdbeAddOp(v, OP_Insert, base, pik_flags);
  if( !pParse->nested ){
    sqlite3VdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
  }
  
  if( isUpdate && rowidChng ){
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
  }
}

/*
** Generate code that will open cursors for a table and for all
** indices of that table.  The "base" parameter is the cursor number used
** for the table.  Indices are opened on subsequent cursors.
*/
void sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int base,        /* 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;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, base, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    VdbeComment((v, "# %s", pIdx->zName));
    sqlite3VdbeOp3(v, op, i+base, pIdx->tnum, (char*)pKey, P3_KEYINFO_HANDOFF);
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
}


#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( pSrc->azColl[i]!=pDest->azColl[i] ){
      return 0;   /* Different sort orders */
    }
  }

  /* 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 counterMem;                  /* Memory register used by AUTOINC */
  int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */

  if( pSelect==0 ){
    return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
  }
  if( pDest->pTrigger ){
    return 0;   /* tab1 must not have triggers */
  }
#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( pDest->isVirtual ){
    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->isDistinct ){
    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, 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->isVirtual ){
    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++;
  counterMem = 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 = sqlite3VdbeAddOp(v, OP_Rewind, iDest, 0);
    emptyDestTest = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
  }else{
    emptyDestTest = 0;
  }
  sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
  emptySrcTest = sqlite3VdbeAddOp(v, OP_Rewind, iSrc, 0);
  if( pDest->iPKey>=0 ){
    addr1 = sqlite3VdbeAddOp(v, OP_Rowid, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
    addr2 = sqlite3VdbeAddOp(v, OP_NotExists, iDest, 0);
    sqlite3VdbeOp3(v, OP_Halt, SQLITE_CONSTRAINT, onError, 
                      "PRIMARY KEY must be unique", P3_STATIC);
    sqlite3VdbeJumpHere(v, addr2);
    autoIncStep(pParse, counterMem);
  }else if( pDest->pIndex==0 ){
    addr1 = sqlite3VdbeAddOp(v, OP_NewRowid, iDest, 0);
  }else{
    addr1 = sqlite3VdbeAddOp(v, OP_Rowid, iSrc, 0);
    assert( pDest->autoInc==0 );
  }
  sqlite3VdbeAddOp(v, OP_RowData, iSrc, 0);
  sqlite3VdbeOp3(v, OP_Insert, iDest,
                    OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND,
                    pDest->zName, 0);
  sqlite3VdbeAddOp(v, OP_Next, iSrc, addr1);
  autoIncEnd(pParse, iDbDest, pDest, counterMem);
  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
    for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
    }
    assert( pSrcIdx );
    sqlite3VdbeAddOp(v, OP_Close, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_Close, iDest, 0);
    sqlite3VdbeAddOp(v, OP_Integer, iDbSrc, 0);
    pKey = sqlite3IndexKeyinfo(pParse, pSrcIdx);
    VdbeComment((v, "# %s", pSrcIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, 
                   (char*)pKey, P3_KEYINFO_HANDOFF);
    sqlite3VdbeAddOp(v, OP_Integer, iDbDest, 0);
    pKey = sqlite3IndexKeyinfo(pParse, pDestIdx);
    VdbeComment((v, "# %s", pDestIdx->zName));
    sqlite3VdbeOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, 
                   (char*)pKey, P3_KEYINFO_HANDOFF);
    addr1 = sqlite3VdbeAddOp(v, OP_Rewind, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_RowKey, iSrc, 0);
    sqlite3VdbeAddOp(v, OP_IdxInsert, iDest, 1);
    sqlite3VdbeAddOp(v, OP_Next, iSrc, addr1+1);
    sqlite3VdbeJumpHere(v, addr1);
  }
  sqlite3VdbeJumpHere(v, emptySrcTest);
  sqlite3VdbeAddOp(v, OP_Close, iSrc, 0);
  sqlite3VdbeAddOp(v, OP_Close, iDest, 0);
  if( emptyDestTest ){
    sqlite3VdbeAddOp(v, OP_Halt, SQLITE_OK, 0);
    sqlite3VdbeJumpHere(v, emptyDestTest);
    sqlite3VdbeAddOp(v, OP_Close, iDest, 0);
    return 0;
  }else{
    return 1;
  }
}
#endif /* SQLITE_OMIT_XFER_OPT */