insert.c

sqlite的最新源码 This ZIP archive contains preprocessed C code for the SQLite library as individual sour

**         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 newIdx = -1;      /* Cursor for the NEW pseudo-table */
  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;    /* 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;           /* 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 */
  int triggers_exist = 0;     /* True if there are FOR EACH ROW triggers */
#endif

  db = pParse->db;
  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( 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
  triggers_exist = sqlite3TriggersExist(pTab, TK_INSERT, 0);
  isView = pTab->pSelect!=0;
#else
# define triggers_exist 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

  /* 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, triggers_exist) ){
    goto insert_cleanup;
  }
  assert( pTab!=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;
  }

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

  /* if there are row triggers, allocate a temp table for new.* references. */
  if( triggers_exist ){
    newIdx = pParse->nTab++;
  }

#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( !triggers_exist );
    assert( pList==0 );
    goto insert_cleanup;
  }
#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);
    if( rc || 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( triggers_exist || readsTable(v, 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 regRowid;    /* Register to hold temp table ROWID */
      int addrTop;     /* Label "L" */
      int addrIf;      /* Address of jump to M */

      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regRowid = 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, regRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrIf);
      sqlite3ReleaseTempReg(pParse, regRec);
      sqlite3ReleaseTempReg(pParse, regRowid);
    }
  }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, 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;
  }

  /* Open the temp table for FOR EACH ROW triggers
  */
  if( triggers_exist ){
    sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
    sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
  }
    
  /* 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;
    int i;

    baseCur = pParse->nTab;
    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, baseCur, OP_OpenWrite);