SQLite

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.191 2004/05/21 01:29:06 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Check to see if the schema for the database needs

/*
** Generate VDBE code that prepares for doing an operation that
** might change the database.
**
** This routine starts a new transaction if we are not already within
** a transaction.  If we are already within a transaction, then a checkpoint
** is set if the setCheckpoint parameter is true.  A checkpoint should
** be set for operations that might fail (due to a constraint) part of
** the way through and which will need to undo some writes without having to
** rollback the whole transaction.  For operations where all constraints
** can be checked before any changes are made to the database, it is never
** necessary to undo a write and the checkpoint should not be set.
**
** Only database iDb and the temp database are made writable by this call.
** If iDb==0, then the main and temp databases are made writable.   If
** iDb==1 then only the temp database is made writable.  If iDb>1 then the
** specified auxiliary database and the temp database are made writable.
*/
void sqlite3BeginWriteOperation(Parse *pParse, int setCheckpoint, int iDb){
  Vdbe *v;
  sqlite *db = pParse->db;
  if( DbHasProperty(db, iDb, DB_Locked) ) return;
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  if( !db->aDb[iDb].inTrans ){
    sqlite3VdbeAddOp(v, OP_Transaction, iDb, 0);
    DbSetProperty(db, iDb, DB_Locked);
    sqlite3CodeVerifySchema(pParse, iDb);
    if( iDb!=1 ){
      sqlite3BeginWriteOperation(pParse, setCheckpoint, 1);
    }
  }else if( setCheckpoint ){
    sqlite3VdbeAddOp(v, OP_Checkpoint, iDb, 0);
    DbSetProperty(db, iDb, DB_Locked);
  }
}

/*
** Generate code that concludes an operation that may have changed
** the database.  If a statement transaction was started, then emit

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.126 2004/05/21 02:14:25 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

char const *sqlite3AffinityString(char affinity){
  switch( affinity ){
    case SQLITE_AFF_INTEGER: return "i";

    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3VdbeAddOp(v, op, 1, dest);
      break;
    }
#if 0
    case TK_IN: {
      int addr;
      sqlite3ExprCode(pParse, pExpr->pLeft);
      addr = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_NotNull, -1, addr+3);
      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp(v, OP_Goto, 0, jumpIfNull ? dest : addr+4);
      if( pExpr->pSelect ){
        sqlite3VdbeAddOp(v, OP_Found, pExpr->iTable, dest);
      }else{
        sqlite3VdbeAddOp(v, OP_SetFound, pExpr->iTable, dest);
      }
      break;
    }
#endif
    case TK_BETWEEN: {
      int addr;
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
      sqlite3ExprCode(pParse, pExpr->pList->a[0].pExpr);
      addr = sqlite3VdbeAddOp(v, OP_Lt, !jumpIfNull, 0);
      sqlite3ExprCode(pParse, pExpr->pList->a[1].pExpr);

**
** 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 1.314 2004/05/21 10:49:48 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  */
  if( pOp->p2 && containsNull && addRowid ){
    pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: Checkpoint P1 * *
**
** Begin a checkpoint.  A checkpoint is the beginning of a operation that

** is part of a larger transaction but which might need to be rolled back
** itself without effecting the containing transaction.  A checkpoint will
** be automatically committed or rollback when the VDBE halts.
**
** The checkpoint is begun on the database file with index P1.  The main
** database file has an index of 0 and the file used for temporary tables
** has an index of 1.
*/
case OP_Checkpoint: {
  int i = pOp->p1;
  if( i>=0 && i<db->nDb && db->aDb[i].pBt && db->aDb[i].inTrans==1 ){
    rc = sqlite3BtreeBeginStmt(db->aDb[i].pBt);
    if( rc==SQLITE_OK ) db->aDb[i].inTrans = 2;
  }
  break;
}

    Release(pTos);
    pTos--;
  }
  if( sqlite3_malloc_failed ) goto no_mem;
  break;
}

/* Opcode: SetFound P1 P2 *
**
** Pop the stack once and compare the value popped off with the
** contents of set P1.  If the element popped exists in set P1,
** then jump to P2.  Otherwise fall through.
*/
case OP_SetFound: {
  int i = pOp->p1;
  assert( pTos>=p->aStack );
  Stringify(pTos);
  if( i>=0 && i<p->nSet && sqlite3HashFind(&p->aSet[i].hash, pTos->z, pTos->n)){
    pc = pOp->p2 - 1;
  }
  Release(pTos);
  pTos--;
  break;
}

/* Opcode: SetNotFound P1 P2 *
**
** Pop the stack once and compare the value popped off with the
** contents of set P1.  If the element popped does not exists in 
** set P1, then jump to P2.  Otherwise fall through.
*/
case OP_SetNotFound: {
  int i = pOp->p1;
  assert( pTos>=p->aStack );
  Stringify(pTos);
  if( i<0 || i>=p->nSet ||
       sqlite3HashFind(&p->aSet[i].hash, pTos->z, pTos->n)==0 ){
    pc = pOp->p2 - 1;
  }
  Release(pTos);
  pTos--;
  break;
}

/* Opcode: SetFirst P1 P2 *
**
** Read the first element from set P1 and push it onto the stack.  If the
** set is empty, push nothing and jump immediately to P2.  This opcode is
** used in combination with OP_SetNext to loop over all elements of a set.
*/
/* Opcode: SetNext P1 P2 *
**
** Read the next element from set P1 and push it onto the stack.  If there
** are no more elements in the set, do not do the push and fall through.
** Otherwise, jump to P2 after pushing the next set element.
*/
case OP_SetFirst: 
case OP_SetNext: {
  Set *pSet;
  CHECK_FOR_INTERRUPT;
  if( pOp->p1<0 || pOp->p1>=p->nSet ){
    if( pOp->opcode==OP_SetFirst ) pc = pOp->p2 - 1;
    break;
  }
  pSet = &p->aSet[pOp->p1];
  if( pOp->opcode==OP_SetFirst ){
    pSet->prev = sqliteHashFirst(&pSet->hash);
    if( pSet->prev==0 ){
      pc = pOp->p2 - 1;
      break;
    }
  }else{
    assert( pSet->prev );
    pSet->prev = sqliteHashNext(pSet->prev);
    if( pSet->prev==0 ){
      break;
    }else{
      pc = pOp->p2 - 1;
    }
  }
  pTos++;
  pTos->z = sqliteHashKey(pSet->prev);
  pTos->n = sqliteHashKeysize(pSet->prev);
  pTos->flags = MEM_Utf8 | MEM_Str | MEM_Ephem;
  break;
}

/* Opcode: Vacuum * * *
**
** Vacuum the entire database.  This opcode will cause other virtual
** machines to be created and run.  It may not be called from within
** a transaction.
*/
case OP_Vacuum: {