SQLite

**    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 SELECT statements in SQLite.
**
** $Id: select.c,v 1.315 2006/06/16 21:13:22 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

  p->n = z ? strlen(z) : 0;
  p->dyn = 0;
}

/*
** Create an expression node for an identifier with the name of zName
*/
Expr *sqlite3CreateIdExpr(const char *zName){
  Token dummy;
  setToken(&dummy, zName);
  return sqlite3Expr(TK_ID, 0, 0, &dummy);
}


/*

  int iRightJoinTable,     /* VDBE cursor for the right table */
  Expr **ppExpr            /* Add the equality term to this expression */
){
  Expr *pE1a, *pE1b, *pE1c;
  Expr *pE2a, *pE2b, *pE2c;
  Expr *pE;

  pE1a = sqlite3CreateIdExpr(zCol);
  pE2a = sqlite3CreateIdExpr(zCol);
  if( zAlias1==0 ){
    zAlias1 = pTab1->zName;
  }
  pE1b = sqlite3CreateIdExpr(zAlias1);
  if( zAlias2==0 ){
    zAlias2 = pTab2->zName;
  }
  pE2b = sqlite3CreateIdExpr(zAlias2);
  pE1c = sqlite3Expr(TK_DOT, pE1b, pE1a, 0);
  pE2c = sqlite3Expr(TK_DOT, pE2b, pE2a, 0);
  pE = sqlite3Expr(TK_EQ, pE1c, pE2c, 0);
  ExprSetProperty(pE, EP_FromJoin);
  pE->iRightJoinTable = iRightJoinTable;
  *ppExpr = sqlite3ExprAnd(*ppExpr, pE);
}

*************************************************************************
** This header file defines the SQLite interface for use by
** shared libraries that want to be imported as extensions into
** an SQLite instance.  Shared libraries that intend to be loaded
** as extensions by SQLite should #include this file instead of 
** sqlite3.h.
**
** @(#) $Id: sqlite3ext.h,v 1.3 2006/06/16 21:13:22 drh Exp $
*/
#ifndef _SQLITE3EXT_H_
#define _SQLITE3EXT_H_
#include <sqlite3.h>

typedef struct sqlite3_api_routines sqlite3_api_routines;

  void * (*commit_hook)(sqlite3*,int(*)(void*),void*);
  int  (*complete)(const char*sql);
  int  (*complete16)(const void*sql);
  int  (*create_collation)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*));
  int  (*create_collation16)(sqlite3*,const char*,int,void*,int(*)(void*,int,const void*,int,const void*));
  int  (*create_function)(sqlite3*,const char*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
  int  (*create_function16)(sqlite3*,const void*,int,int,void*,void (*xFunc)(sqlite3_context*,int,sqlite3_value**),void (*xStep)(sqlite3_context*,int,sqlite3_value**),void (*xFinal)(sqlite3_context*));
  int (*create_module)(sqlite3*,const char*,const sqlite3_module*,void*);
  int  (*data_count)(sqlite3_stmt*pStmt);
  sqlite3 * (*db_handle)(sqlite3_stmt*);
  int (*declare_vtab)(sqlite3*,const char*);
  int  (*enable_shared_cache)(int);
  int  (*errcode)(sqlite3*db);
  const char * (*errmsg)(sqlite3*);
  const void * (*errmsg16)(sqlite3*);

/*
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.509 2006/06/16 21:13:22 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/

int sqlite3ExprCheck(Parse*, Expr*, int, int*);
int sqlite3ExprCompare(Expr*, Expr*);
int sqliteFuncId(Token*);
int sqlite3ExprResolveNames(NameContext *, Expr *);
int sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
int sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
Vdbe *sqlite3GetVdbe(Parse*);
Expr *sqlite3CreateIdExpr(const char*);
void sqlite3Randomness(int, void*);
void sqlite3RollbackAll(sqlite3*);
void sqlite3CodeVerifySchema(Parse*, int);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3CommitTransaction(Parse*);
void sqlite3RollbackTransaction(Parse*);
int sqlite3ExprIsConstant(Expr*);

**    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 UPDATE statements.
**
** $Id: update.c,v 1.127 2006/06/16 21:13:22 drh Exp $
*/
#include "sqliteInt.h"

/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
  SrcList *pSrc,       /* The virtual table to be modified */
  Table *pTab,         /* The virtual table */
  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
  Expr *pRowidExpr,    /* Expression used to recompute the rowid */
  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
  Expr *pWhere         /* WHERE clause of the UPDATE statement */
);

/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the 

      apIdx[nIdx++] = pIdx;
      aIdxUsed[j] = 1;
    }else{
      aIdxUsed[j] = 0;
    }
  }








  /* Start the view context
  */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);

#ifndef SQLITE_OMIT_VIRTUALTABLE
  /* Virtual tables must be handled separately */
  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere);
    pWhere = 0;
    pTabList = 0;
    goto update_cleanup;
  }
#endif

  /* Resolve the column names in all the expressions in the
  ** WHERE clause.
  */
  if( sqlite3ExprResolveNames(&sNC, pWhere) ){
    goto update_cleanup;
  }

  /* If we are trying to update a view, realize that view into
  ** a ephemeral table.
  */
  if( isView ){
    Select *pView;
    pView = sqlite3SelectDup(pTab->pSelect);

    }

    /* Create the new index entries and the new record.
    */
    sqlite3CompleteInsertion(pParse, pTab, iCur, aIdxUsed, chngRowid, 1, -1);
  }






































  /* Increment the row counter 
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
    sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
  }

  /* If there are triggers, close all the cursors after each iteration

  /* Repeat the above with the next record to be updated, until
  ** all record selected by the WHERE clause have been updated.
  */
  sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
  sqlite3VdbeJumpHere(v, addr);

  /* Close all tables if there were no FOR EACH ROW triggers */
  if( !triggers_exist ){
    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
      if( openAll || aIdxUsed[i] ){
        sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
      }
    }
    sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
  }else{

  sqliteFree(apIdx);
  sqliteFree(aXRef);
  sqlite3SrcListDelete(pTabList);
  sqlite3ExprListDelete(pChanges);
  sqlite3ExprDelete(pWhere);
  return;
}

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Generate code for an UPDATE of a virtual table.
**
** The strategy is that we create an ephemerial table that contains
** for each row to be changed:
**
**   (A)  The original rowid of that row.
**   (B)  The revised rowid for the row. (note1)
**   (C)  The content of every column in the row.
**
** Then we loop over this ephemeral table and for each row in
** the ephermeral table call VUpdate.
**
** When finished, drop the ephemeral table.
**
** (note1) Actually, if we know in advance that (A) is always the same
** as (B) we only store (A), then duplicate (A) when pulling
** it out of the ephemeral table before calling VUpdate.
*/
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
  SrcList *pSrc,       /* The virtual table to be modified */
  Table *pTab,         /* The virtual table */
  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
  Expr *pRowid,        /* Expression used to recompute the rowid */
  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
  Expr *pWhere         /* WHERE clause of the UPDATE statement */
){
  Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
  ExprList *pEList = 0;     /* The result set of the SELECT statement */
  Select *pSelect = 0;      /* The SELECT statement */
  Expr *pExpr;              /* Temporary expression */
  int ephemTab;             /* Table holding the result of the SELECT */
  int i;                    /* Loop counter */
  int addr;                 /* Address of top of loop */

  /* Construct the SELECT statement that will find the new values for
  ** all updated rows. 
  */
  pEList = sqlite3ExprListAppend(0, sqlite3CreateIdExpr("_rowid_"), 0);
  if( pRowid ){
    pEList = sqlite3ExprListAppend(pEList, pRowid, 0);
  }
  for(i=0; i<pTab->nCol; i++){
    if( i==pTab->iPKey ){
      pExpr = sqlite3Expr(TK_NULL, 0, 0, 0);
    }else if( aXRef[i]>=0 ){
      pExpr = sqlite3ExprDup(pChanges->a[aXRef[i]].pExpr);
    }else{
      pExpr = sqlite3CreateIdExpr(pTab->aCol[i].zName);
    }
    pEList = sqlite3ExprListAppend(pEList, pExpr, 0);
  }
  pSelect = sqlite3SelectNew(pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
  
  /* Create the ephemeral table into which the update results will
  ** be stored.
  */
  assert( v );
  ephemTab = pParse->nTab++;
  sqlite3VdbeAddOp(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));

  /* fill the ephemeral table 
  */
  sqlite3Select(pParse, pSelect, SRT_Table, ephemTab, 0, 0, 0, 0);

  /*
  ** Generate code to scan the ephemeral table and call VDelete and
  ** VInsert
  */
  sqlite3VdbeAddOp(v, OP_Rewind, ephemTab, 0);
  addr = sqlite3VdbeCurrentAddr(v);
  sqlite3VdbeAddOp(v, OP_Column,  ephemTab, 0);
  if( pRowid ){
    sqlite3VdbeAddOp(v, OP_Column, ephemTab, 1);
  }else{
    sqlite3VdbeAddOp(v, OP_Dup, 1, 0);
  }
  for(i=0; i<pTab->nCol; i++){
    sqlite3VdbeAddOp(v, OP_Column, ephemTab, i+1+(pRowid!=0));
  }
  sqlite3VdbeOp3(v, OP_VUpdate, 0, pTab->nCol+2, 
                     (const char*)pTab->pVtab, P3_VTAB);
  sqlite3VdbeAddOp(v, OP_Next, ephemTab, addr);
  sqlite3VdbeAddOp(v, OP_Close, ephemTab, 0);

  /* Cleanup */
  sqlite3SelectDelete(pSelect);  
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.564 2006/06/16 21:13:22 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

    }
  }

  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

















#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VUpdate P1 P2 P3
**
** P3 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xUpdate method. P2 values
** are taken from the stack to pass to the xUpdate invocation. The
** value on the top of the stack corresponds to the p2th element 
** of the argv array passed to xUpdate.
**
** The xUpdate method will do a DELETE or an INSERT or both.
** The argv[0] element (which corresponds to the P2-th element down
** on the stack) is the rowid of a row to delete.  If argv[0] is
** NULL then no deletion occurs.  The argv[1] element is the rowid
** of the new row.  This can be NULL to have the virtual table
** select the new rowid for itself.  The higher elements in the
** stack are the values of columns in the new row.




**
** If P2==1 then no insert is performed.  argv[0] is the rowid of
** a row to delete.
**
** P1 is a boolean flag. If it is set to true and the xUpdate call
** is successful, then the value returned by sqlite3_last_insert_rowid() 
** is set to the value of the rowid for the row just inserted.

    rc = SQLITE_ERROR;
  }else{
    int i;
    sqlite_int64 rowid;
    Mem **apArg = p->apArg;
    Mem *pX = &pTos[1-nArg];
    for(i = 0; i<nArg; i++, pX++){
      storeTypeInfo(pX, 0);
      apArg[i] = pX;
    }
    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    rc = pModule->xUpdate(pVtab, nArg, apArg, &rowid);
    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
    if( pOp->p1 && rc==SQLITE_OK ){
      assert( nArg>1 && apArg[0] && (apArg[0]->flags&MEM_Null) );
      db->lastRowid = rowid;

# 2006 June 10
#
# 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.  The
# focus of this file is creating and dropping virtual tables.
#
# $Id: vtab1.test,v 1.19 2006/06/16 21:13:23 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !vtab {
  finish_test
  return

} [list xBestIndex {SELECT rowid, * FROM 'treal'} \
        xFilter    {SELECT rowid, * FROM 'treal'} ]

execsql {
  DROP TABLE t1;
  DROP TABLE treal;
}

if 0 {   # FIXME

#----------------------------------------------------------------------
# Test cases vtab1-6 test INSERT, UPDATE and DELETE operations 
# on virtual tables.
do_test vtab1-6-1 {
  execsql { SELECT sql FROM sqlite_master }
} {}

do_test vtab1-6-7 {
  execsql {
    DELETE FROM techo;
    SELECT * FROM techo;
  }
} {}


file delete -force test2.db
file delete -force test2.db-journal
sqlite3 db2 test2.db
execsql {
  CREATE TABLE techo(a PRIMARY KEY, b, c);
} db2

] {
  execsql $stmt
  execsql $stmt db2
  check_echo_table vtab1-6.8.[incr tn]
}

db2 close



#----------------------------------------------------------------------
# Test cases vtab1-7 tests that the value returned by 
# sqlite3_last_insert_rowid() is set correctly when rows are inserted
# into virtual tables.
do_test vtab1.7-1 {
  execsql {

  }
} {31429}
do_test vtab1.7-13 {
  execsql {
    SELECT rowid, a, b, c FROM real_abc
  }
} {}
} ;# END if 0

finish_test