SQLite

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.146 2003/04/17 22:57:53 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

                        sizeof(int)*pList->nId );
  if( pIndex==0 ) goto exit_create_index;
  pIndex->aiColumn = (int*)&pIndex[1];
  pIndex->zName = (char*)&pIndex->aiColumn[pList->nId];
  strcpy(pIndex->zName, zName);
  pIndex->pTable = pTab;
  pIndex->nColumn = pList->nId;
  pIndex->onError = pIndex->isUnique = onError;
  pIndex->autoIndex = pName==0;
  pIndex->iDb = isTemp ? 1 : pParse->iDb;

  /* Scan the names of the columns of the table to be indexed and
  ** load the column indices into the Index structure.  Report an error
  ** if any column is not found.
  */

/*
** 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 1.175 2003/04/17 22:57:54 drh Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"

#endif
#ifndef SQLITE_OMIT_AUTHORIZATION
  int (*xAuth)(void*,int,const char*,const char*); /* Access Auth function */
  void *pAuthArg;               /* 1st argument to the access auth function */
#endif
};

/*
** The following are the indices of in sqlite.aDb[] of the main database
** file and the file used to store TEMP tables.
*/
#define DB_TMP     0
#define DB_MAIN    1

/*
** Possible values for the sqlite.flags.
*/
#define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
#define SQLITE_Initialized    0x00000002  /* True after initialization */
#define SQLITE_Interrupt      0x00000004  /* Cancel current operation */
#define SQLITE_InTrans        0x00000008  /* True if in a transaction */

** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
**
** Each REFERENCES clause generates an instance of the following structure
** which is attached to the from-table.  The to-table need not exist when
** the from-table is created.  The existance of the to-table is not checked
** until an attempt is made to insert data into the from-table.
**
** The sqlite.aFKey hash table stores pointers to to this structure
** given the name of a to-table.  For each to-table, all foreign keys
** associated with that table are on a linked list using the FKey.pNextTo
** field.
*/
struct FKey {
  Table *pFrom;     /* The table that constains the REFERENCES clause */
  FKey *pNextFrom;  /* Next foreign key in pFrom */

** In the Table structure describing Ex1, nCol==3 because there are
** three columns in the table.  In the Index structure describing
** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 
** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
** The second column to be indexed (c1) has an index of 0 in
** Ex1.aCol[], hence Ex2.aiColumn[1]==0.







*/
struct Index {
  char *zName;     /* Name of this index */
  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 isUnique;     /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
  Index *pNext;    /* The next index associated with the same table */
};

/*

 * 2. All triggers associated with a single table form a linked list, using the
 *    pNext member of struct Trigger. A pointer to the first element of the
 *    linked list is stored as the "pTrigger" member of the associated
 *    struct Table.
 *
 * The "step_list" member points to the first element of a linked list
 * containing the SQL statements specified as the trigger program.
 *
 * When a trigger is initially created, the "isCommit" member is set to FALSE.
 * When a transaction is rolled back, any Trigger structures with "isCommit" set
 * to FALSE are deleted by the logic in sqliteRollbackInternalChanges(). When
 * a transaction is commited, the "isCommit" member is set to TRUE for any
 * Trigger structures for which it is FALSE.
 *
 * When a trigger is dropped, using the sqliteDropTrigger() interfaced, it is 
 * removed from the trigHash hash table and added to the trigDrop hash table.
 * If the transaction is rolled back, the trigger is re-added into the trigHash
 * hash table (and hence the database schema). If the transaction is commited,
 * then the Trigger structure is deleted permanently.
 */
struct Trigger {
  char *name;             /* The name of the trigger                        */
  char *table;            /* The table or view to which the trigger applies */
  int iDb;                /* Database containing this trigger               */
  int op;                 /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  int tr_tm;              /* One of TK_BEFORE, TK_AFTER */