insert.c

嵌入式数据系统软件！

/*
** 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 1.197 2007/12/14 16:11:09 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P3 of the most recently inserted opcode to a column affinity
** string for 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
*/
void 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 *)sqlite3DbMallocZero(db, pIdx->nColumn+1);
    if( !pIdx->zColAff ){
      return;
    }
    for(n=0; n<pIdx->nColumn; n++){
      pIdx->zColAff[n] = pTab->aCol[pIdx->aiColumn[n]].affinity;
    }
    pIdx->zColAff[pIdx->nColumn] = '\0';
  }
 
  sqlite3VdbeChangeP3(v, -1, pIdx->zColAff, 0);
}

/*
** Set P3 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 *)sqlite3DbMallocZero(db, pTab->nCol+1);
    if( !zColAff ){
      return;
    }

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

    pTab->zColAff = zColAff;
  }

  sqlite3VdbeChangeP3(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(Vdbe *v, int iStartAddr, int iDb, Table *pTab){
  int i;
  int iEnd = sqlite3VdbeCurrentAddr(v);
  for(i=iStartAddr; i<iEnd; i++){
    VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
    assert( pOp!=0 );
    if( pOp->opcode==OP_OpenRead ){
      VdbeOp *pPrior = &pOp[-1];
      int tnum = pOp->p2;
      assert( i>iStartAddr );
      assert( pPrior->opcode==OP_Integer );
      if( pPrior->p1==iDb ){
        Index *pIndex;
        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->p3==(const char*)pTab->pVtab ){
      assert( pOp->p3!=0 );
      assert( pOp->p3type==P3_VTAB );
      return 1;
    }
#endif
  }
  return 0;
}

#ifndef SQLITE_OMIT_AUTOINCREMENT
/*
** Write out code to initialize the autoincrement logic.  This code
** looks up the current autoincrement value in the sqlite_sequence
** table and stores that value in a memory cell.  Code generated by
** autoIncStep() will keep that memory cell holding the largest
** rowid value.  Code generated by autoIncEnd() will write the new
** largest value of the counter back into the sqlite_sequence table.
**
** This routine returns the index of the mem[] cell that contains
** the maximum rowid counter.
**
** Two memory cells are allocated.  The next memory cell after the
** one returned holds the rowid in sqlite_sequence where we will
** write back the revised maximum rowid.
*/
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;
  if( pTab->autoInc ){
    Vdbe *v = pParse->pVdbe;
    Db *pDb = &pParse->db->aDb[iDb];
    int iCur = pParse->nTab;
    int addr;
    assert( v );
    addr = sqlite3VdbeCurrentAddr(v);
    memId = pParse->nMem+1;
    pParse->nMem += 2;
    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
    sqlite3VdbeAddOp(v, OP_Rewind, iCur, addr+13);
    sqlite3VdbeAddOp(v, OP_Column, iCur, 0);
    sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->zName, 0);
    sqlite3VdbeAddOp(v, OP_Ne, 0x100, addr+12);
    sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, memId-1, 1);
    sqlite3VdbeAddOp(v, OP_Column, iCur, 1);
    sqlite3VdbeAddOp(v, OP_MemStore, memId, 1);
    sqlite3VdbeAddOp(v, OP_Goto, 0, addr+13);
    sqlite3VdbeAddOp(v, OP_Next, iCur, addr+4);
    sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
  }
  return memId;
}

/*
** 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){
  if( memId>0 ){
    sqlite3VdbeAddOp(pParse->pVdbe, OP_MemMax, memId, 0);
  }
}

/*
** After doing one or more inserts, the maximum rowid is stored
** in mem[memId].  Generate code to write this value back into the
** the sqlite_sequence table.
*/
static void autoIncEnd(
  Parse *pParse,     /* The parsing context */
  int iDb,           /* Index of the database holding pTab */
  Table *pTab,       /* Table we are inserting into */
  int memId          /* Memory cell holding the maximum rowid */
){
  if( pTab->autoInc ){
    int iCur = pParse->nTab;
    Vdbe *v = pParse->pVdbe;
    Db *pDb = &pParse->db->aDb[iDb];
    int addr;
    assert( v );
    addr = sqlite3VdbeCurrentAddr(v);
    sqlite3OpenTable(pParse, iCur, iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
    sqlite3VdbeAddOp(v, OP_MemLoad, memId-1, 0);
    sqlite3VdbeAddOp(v, OP_NotNull, -1, addr+7);
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp(v, OP_NewRowid, iCur, 0);
    sqlite3VdbeOp3(v, OP_String8, 0, 0, pTab->zName, 0);
    sqlite3VdbeAddOp(v, OP_MemLoad, memId, 0);
    sqlite3VdbeAddOp(v, OP_MakeRecord, 2, 0);
    sqlite3VdbeAddOp(v, OP_Insert, iCur, OPFLAG_APPEND);
    sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
  }
}
#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)
# define autoIncEnd(A,B,C,D)
#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.  The template looks like this:
**
**         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 second 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 third 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:
**
**         goto B
**      A: setup for the SELECT
**         loop over the rows in the SELECT
**           gosub C
**         end loop
**         cleanup after the SELECT
**         goto D
**      B: open write cursor to <table> and its indices
**         goto A
**      C: insert the select result into <table>
**         return
**      D: cleanup
**
** The fourth 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:
**
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           gosub C
**         end loop
**         cleanup after the SELECT
**         goto D
**      C: insert the select result into the intermediate table
**         return
**      B: open a cursor to an intermediate table
**         goto A
**      D: open write cursor to <table> and its indices
**         loop over the intermediate table
**           transfer values form intermediate table into <table>
**         end the loop
**         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 */
){
  Table *pTab;          /* The table to insert into */
  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 base = 0;         /* VDBE Cursor number for pTab */
  int iCont=0,iBreak=0; /* Beginning and end of the loop over srcTab */
  sqlite3 *db;          /* The main database structure */
  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 iSelectLoop = 0;  /* Address of code that implements the SELECT */
  int iCleanup = 0;     /* Address of the cleanup code */
  int iInsertBlock = 0; /* Address of the subroutine used to insert data */
  int iCntMem = 0;      /* Memory cell used for the row counter */
  int newIdx = -1;      /* Cursor for the NEW table */
  Db *pDb;              /* The database containing table being inserted into */
  int counterMem = 0;   /* Memory cell holding AUTOINCREMENT counter */
  int appendFlag = 0;   /* True if the insert is likely to be an append */
  int iDb;

  int nHidden = 0;

#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(pParse, pTab, TK_INSERT, 0);
  isView = pTab->pSelect!=0;