SQLite

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.148 2003/04/21 18:48:46 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

    if( p==0 && pParse->useDb==1 && zDbase==0 ){
      p = sqliteFindTable(db, zName, 0);
    }
  }
  if( p==0 ){
    if( zDbase ){
      sqliteErrorMsg(pParse, "no such table: %s.%s", zDbase, zName);
    }else if( (pParse->useDb==0 || pParse->useDb>=2) 
               && sqliteFindTable(db, zName, 0)!=0 ){
      sqliteErrorMsg(pParse, "table \"%s\" is not in database \"%s\"",
         zName, zUse);
    }else{
      sqliteErrorMsg(pParse, "no such table: %s", zName);
    }
  }
  return p;
}

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.96 2003/04/21 18:48:46 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  if( pParse->zErrMsg==0 ){

minus_num(A) ::= MINUS number(X).     {A = X;}
number(A) ::= INTEGER(X).  {A = X;}
number(A) ::= FLOAT(X).    {A = X;}
plus_opt ::= PLUS.
plus_opt ::= .

//////////////////////////// The CREATE TRIGGER command /////////////////////



cmd ::= CREATE(A) trigger_decl BEGIN trigger_cmd_list(S) END(Z). {

  Token all;
  all.z = A.z;
  all.n = (Z.z - A.z) + Z.n;
  sqliteFinishTrigger(pParse, S, &all);
}

trigger_decl ::= temp(T) TRIGGER nm(B) trigger_time(C) trigger_event(D)
                 ON nm(E) dbnm(DB) foreach_clause(F) when_clause(G). {
  SrcList *pTab = sqliteSrcListAppend(0, &E, &DB);
  sqliteBeginTrigger(pParse, &B, C, D.a, D.b, pTab, F, G, T);
}

%type trigger_time  {int}
trigger_time(A) ::= BEFORE.      { A = TK_BEFORE; }
trigger_time(A) ::= AFTER.       { A = TK_AFTER;  }
trigger_time(A) ::= INSTEAD OF.  { A = TK_INSTEAD;}
trigger_time(A) ::= .            { A = TK_BEFORE; }

foreach_clause(A) ::= FOR EACH STATEMENT. { A = TK_STATEMENT; }

%type when_clause {Expr *}
when_clause(A) ::= .             { A = 0; }
when_clause(A) ::= WHEN expr(X). { A = X; }

%type trigger_cmd_list {TriggerStep *}
%destructor trigger_cmd_list {sqliteDeleteTriggerStep($$);}
trigger_cmd_list(A) ::= trigger_cmd(X) SEMI trigger_cmd_list(Y). {
  X->pNext = Y;
  A = X;
}
trigger_cmd_list(A) ::= . { A = 0; }

%type trigger_cmd {TriggerStep *}
%destructor trigger_cmd {sqliteDeleteTriggerStep($$);}
// UPDATE 
trigger_cmd(A) ::= UPDATE orconf(R) nm(X) SET setlist(Y) where_opt(Z).  
               { A = sqliteTriggerUpdateStep(&X, Y, Z, R); }

// INSERT
trigger_cmd(A) ::= INSERT orconf(R) INTO nm(X) inscollist_opt(F) 
  VALUES LP itemlist(Y) RP.  

/*
** 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 1.177 2003/04/21 18:48:47 drh Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"

  int newTnum;         /* Table number to use when reparsing CREATE TABLEs */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nAgg;            /* Number of aggregate expressions */
  AggExpr *aAgg;       /* An array of aggregate expressions */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  TriggerStack *trigStack;  /* Trigger actions being coded */
};

/*
 * Each trigger present in the database schema is stored as an instance of
 * struct Trigger. 
 *
 * Pointers to instances of struct Trigger are stored in two ways.
 * 1. In the "trigHash" hash table (part of the sqlite* that represents the 
 *    database). This allows Trigger structures to be retrieved by name.
 * 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.
 */
struct Trigger {
  char *name;             /* The name of the trigger                        */
  char *table;            /* The table or view to which the trigger applies */
  u8 iDb;                 /* Database containing this trigger               */
  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  u8 tr_tm;               /* One of TK_BEFORE, TK_AFTER */
  Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                             the <column-list> is stored here */
  int foreach;            /* One of TK_ROW or TK_STATEMENT */

  TriggerStep *step_list; /* Link list of trigger program steps             */
  Trigger *pNext;         /* Next trigger associated with the table */

Select *sqliteSelectDup(Select*);
FuncDef *sqliteFindFunction(sqlite*,const char*,int,int,int);
void sqliteRegisterBuiltinFunctions(sqlite*);
int sqliteSafetyOn(sqlite*);
int sqliteSafetyOff(sqlite*);
int sqliteSafetyCheck(sqlite*);
void sqliteChangeCookie(sqlite*, Vdbe*);
void sqliteBeginTrigger(Parse*, Token*,int,int,IdList*,SrcList*,int,Expr*,int);
void sqliteFinishTrigger(Parse*, TriggerStep*, Token*);
void sqliteDropTrigger(Parse*, SrcList*, int);
int sqliteTriggersExist(Parse* , Trigger* , int , int , int, ExprList*);
int sqliteCodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int, 
                         int, int);
void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
void sqliteDeleteTriggerStep(TriggerStep*);
TriggerStep *sqliteTriggerSelectStep(Select*);
TriggerStep *sqliteTriggerInsertStep(Token*, IdList*, ExprList*, Select*, int);
TriggerStep *sqliteTriggerUpdateStep(Token*, ExprList*, Expr*, int);
TriggerStep *sqliteTriggerDeleteStep(Token*, Expr*);
void sqliteDeleteTrigger(Trigger*);
int sqliteJoinType(Parse*, Token*, Token*, Token*);
void sqliteCreateForeignKey(Parse*, IdList*, Token*, IdList*, int);

*************************************************************************
** An tokenizer for SQL
**
** This file contains C code that splits an SQL input string up into
** individual tokens and sends those tokens one-by-one over to the
** parser for analysis.
**
** $Id: tokenize.c,v 1.58 2003/04/21 18:48:47 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include <stdlib.h>

/*

  if( pParse->pVdbe && (pParse->useCallback || pParse->nErr>0) ){
    sqliteVdbeDelete(pParse->pVdbe);
    pParse->pVdbe = 0;
  }
  if( pParse->pNewTable ){
    sqliteDeleteTable(pParse->db, pParse->pNewTable);
    pParse->pNewTable = 0;
  }
  if( pParse->pNewTrigger ){
    sqliteDeleteTrigger(pParse->pNewTrigger);
    pParse->pNewTrigger = 0;
  }
  if( nErr>0 && (pParse->rc==SQLITE_OK || pParse->rc==SQLITE_DONE) ){
    pParse->rc = SQLITE_ERROR;
  }
  return nErr;
}

*
*/
#include "sqliteInt.h"

/*
** Delete a linked list of TriggerStep structures.
*/
void sqliteDeleteTriggerStep(TriggerStep *pTriggerStep){
  while( pTriggerStep ){
    TriggerStep * pTmp = pTriggerStep;
    pTriggerStep = pTriggerStep->pNext;

    if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z);
    sqliteExprDelete(pTmp->pWhere);
    sqliteExprListDelete(pTmp->pExprList);
    sqliteSelectDelete(pTmp->pSelect);
    sqliteIdListDelete(pTmp->pIdList);

    sqliteFree(pTmp);
  }
}

/*
** This is called by the parser when it sees a CREATE TRIGGER statement
** up to the point of the BEGIN before the trigger actions.  A Trigger
** structure is generated based on the information available and stored
** in pParse->pNewTrigger.  After the trigger actions have been parsed, the
** sqliteFinishTrigger() function is called to complete the trigger
** construction process.
*/
void sqliteBeginTrigger(
  Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */
  Token *pName,       /* The name of the trigger */
  int tr_tm,          /* One of TK_BEFORE, TK_AFTER , TK_INSTEAD */
  int op,             /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
  IdList *pColumns,   /* column list if this is an UPDATE OF trigger */
  SrcList *pTableName,/* The name of the table/view the trigger applies to */
  int foreach,        /* One of TK_ROW or TK_STATEMENT */
  Expr *pWhen,        /* WHEN clause */
  int isTemp          /* True if the TEMPORARY keyword is present */

){
  Trigger *nt;
  Table   *tab;
  char *zName = 0;        /* Name of the trigger */
  sqlite *db = pParse->db;
  int iDb;                /* When database to store the trigger in */

  /* Check that: 
  ** 1. the trigger name does not already exist.
  ** 2. the table (or view) does exist in the same database as the trigger.
  ** 3. that we are not trying to create a trigger on the sqlite_master table
  ** 4. That we are not trying to create an INSTEAD OF trigger on a table.
  ** 5. That we are not trying to create a BEFORE or AFTER trigger on a view.
  */
  if( sqlite_malloc_failed ) goto trigger_cleanup;
  assert( pTableName->nSrc==1 );
  tab = sqliteSrcListLookup(pParse, pTableName);
  if( !tab ){
    goto trigger_cleanup;
  }
  iDb = isTemp ? 1 : tab->iDb;
  if( iDb>=2 && !pParse->initFlag ){
    sqliteErrorMsg(pParse, "triggers may not be added to auxiliary "
       "database %s", db->aDb[tab->iDb].zName);
    goto trigger_cleanup;
  }

  zName = sqliteStrNDup(pName->z, pName->n);
  if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){
    sqliteErrorMsg(pParse, "trigger %T already exists", pName);
    goto trigger_cleanup;
  }
  if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){
    sqliteErrorMsg(pParse, "cannot create trigger on system table");
    pParse->nErr++;
    goto trigger_cleanup;

    sqliteErrorMsg(pParse, "cannot create INSTEAD OF"
        " trigger on table: %S", pTableName, 0);
    goto trigger_cleanup;
  }
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_CREATE_TRIGGER;
    if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
    if( sqliteAuthCheck(pParse, code, zName, tab->zName) ){
      goto trigger_cleanup;
    }
    if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0)){
      goto trigger_cleanup;
    }
  }
#endif

  if (tr_tm == TK_INSTEAD){
    tr_tm = TK_BEFORE;
  }

  /* Build the Trigger object */
  nt = (Trigger*)sqliteMalloc(sizeof(Trigger));
  if( nt==0 ) goto trigger_cleanup;
  nt->name = zName;
  zName = 0;
  nt->table = sqliteStrDup(pTableName->a[0].zName);
  if( sqlite_malloc_failed ) goto trigger_cleanup;
  nt->iDb = iDb;
  nt->op = op;
  nt->tr_tm = tr_tm;
  nt->pWhen = sqliteExprDup(pWhen);

  nt->pColumns = sqliteIdListDup(pColumns);
  nt->foreach = foreach;
  assert( pParse->pNewTrigger==0 );
  pParse->pNewTrigger = nt;

trigger_cleanup:
  sqliteFree(zName);
  sqliteSrcListDelete(pTableName);
  sqliteIdListDelete(pColumns);
  sqliteExprDelete(pWhen);
}

/*
** This routine is called after all of the trigger actions have been parsed
** in order to complete the process of building the trigger.
*/
void sqliteFinishTrigger(
  Parse *pParse,          /* Parser context */
  TriggerStep *pStepList, /* The triggered program */
  Token *pAll             /* Token that describes the complete CREATE TRIGGER */
){
  Trigger *nt;              /* The trigger whose construction is finishing up */
  sqlite *db = pParse->db;  /* The database */

  if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup;
  nt = pParse->pNewTrigger;
  pParse->pNewTrigger = 0;
  nt->step_list = pStepList;
  while( pStepList ){
    pStepList->pTrig = nt;
    pStepList = pStepList->pNext;
  }


  /* if we are not initializing, and this trigger is not on a TEMP table, 
  ** build the sqlite_master entry
  */
  if( !pParse->initFlag ){
    static VdbeOp insertTrig[] = {
      { OP_NewRecno,   0, 0,  0          },
      { OP_String,     0, 0,  "trigger"  },
      { OP_String,     0, 0,  0          },  /* 2: trigger name */
      { OP_String,     0, 0,  0          },  /* 3: table name */
      { OP_Integer,    0, 0,  0          },
      { OP_String,     0, 0,  0          },  /* 5: SQL */
      { OP_MakeRecord, 5, 0,  0          },
      { OP_PutIntKey,  0, 0,  0          },
    };
    int addr;
    Vdbe *v;

    /* Make an entry in the sqlite_master table */
    v = sqliteGetVdbe(pParse);
    if( v==0 ) goto triggerfinish_cleanup;
    sqliteBeginWriteOperation(pParse, 0, 0);
    sqliteOpenMasterTable(v, nt->iDb==1);
    addr = sqliteVdbeAddOpList(v, ArraySize(insertTrig), insertTrig);


    sqliteVdbeChangeP3(v, addr+2, nt->name, 0); 
    sqliteVdbeChangeP3(v, addr+3, nt->table, 0); 
    sqliteVdbeChangeP3(v, addr+5, pAll->z, pAll->n);
    if( nt->iDb==0 ){
      sqliteChangeCookie(db, v);
    }
    sqliteVdbeAddOp(v, OP_Close, 0, 0);
    sqliteEndWriteOperation(pParse);
  }

  if( !pParse->explain ){
    Table *pTab;
    sqliteHashInsert(&db->aDb[nt->iDb].trigHash, 
                     nt->name, strlen(nt->name)+1, nt);
    pTab = sqliteLocateTable(pParse, nt->table, 0);
    assert( pTab!=0 );
    nt->pNext = pTab->pTrigger;
    pTab->pTrigger = nt;


  }else{


    sqliteDeleteTrigger(nt);
  }

triggerfinish_cleanup:
  sqliteDeleteTrigger(pParse->pNewTrigger);




  pParse->pNewTrigger = 0;
  sqliteDeleteTriggerStep(pStepList);
}

/*
** Make a copy of all components of the given trigger step.  This has
** the effect of copying all Expr.token.z values into memory obtained
** from sqliteMalloc().  As initially created, the Expr.token.z values

  return pTriggerStep;
}

/* 
** Recursively delete a Trigger structure
*/
void sqliteDeleteTrigger(Trigger *pTrigger){
  if( pTrigger==0 ) return;
  sqliteDeleteTriggerStep(pTrigger->step_list);
  sqliteFree(pTrigger->name);
  sqliteFree(pTrigger->table);
  sqliteExprDelete(pTrigger->pWhen);
  sqliteIdListDelete(pTrigger->pColumns);
  sqliteFree(pTrigger);
}

    pTrigger = sqliteHashFind(&(db->aDb[j].trigHash), zName, nName+1);
    if( pTrigger ) break;
  }
  if( !pTrigger ){
    sqliteErrorMsg(pParse, "no such trigger: %S", pName, 0);
    goto drop_trigger_cleanup;
  }
  assert( pTrigger->iDb<db->nDb );
  if( pTrigger->iDb>=2 ){
    sqliteErrorMsg(pParse, "triggers may not be removed from "
       "auxiliary database %s", db->aDb[pTrigger->iDb].zName);
    goto drop_trigger_cleanup;
  }
  pTable = sqliteFindTable(db, pTrigger->table, db->aDb[pTrigger->iDb].zName);
  assert(pTable);
  assert( pTable->iDb==pTrigger->iDb || pTrigger->iDb==1 );
#ifndef SQLITE_OMIT_AUTHORIZATION
  {
    int code = SQLITE_DROP_TRIGGER;
    if( pTrigger->iDb ) code = SQLITE_DROP_TEMP_TRIGGER;
    if( sqliteAuthCheck(pParse, code, pTrigger->name, pTable->zName) ||
      sqliteAuthCheck(pParse, SQLITE_DELETE, SCHEMA_TABLE(pTrigger->iDb),0) ){
      goto drop_trigger_cleanup;
    }
  }
#endif

  /* Generate code to destroy the database record of the trigger.
  */
  if( pTable!=0 && !nested && (v = sqliteGetVdbe(pParse))!=0 ){
    int base;
    static VdbeOp dropTrigger[] = {
      { OP_Rewind,     0, ADDR(8),  0},
      { OP_String,     0, 0,        0}, /* 1 */
      { OP_MemStore,   1, 1,        0},
      { OP_MemLoad,    1, 0,        0}, /* 3 */
      { OP_Column,     0, 1,        0},
      { OP_Ne,         0, ADDR(7),  0},
      { OP_Delete,     0, 0,        0},
      { OP_Next,       0, ADDR(3),  0}, /* 7 */
    };

    sqliteBeginWriteOperation(pParse, 0, 0);
    sqliteOpenMasterTable(v, pTrigger->iDb);
    base = sqliteVdbeAddOpList(v,  ArraySize(dropTrigger), dropTrigger);
    sqliteVdbeChangeP3(v, base+1, zName, 0);
    if( pTrigger->iDb==0 ){
      sqliteChangeCookie(db, v);
    }
    sqliteVdbeAddOp(v, OP_Close, 0, 0);
    sqliteEndWriteOperation(pParse);
  }

  /*
   * If this is not an "explain", then delete the trigger structure.
   */
  if( !pParse->explain ){
    if( pTable->pTrigger == pTrigger ){
      pTable->pTrigger = pTrigger->pNext;

      }
      assert(cc);
    }
    sqliteHashInsert(&(db->aDb[pTrigger->iDb].trigHash), zName, nName+1, 0);
    sqliteDeleteTrigger(pTrigger);
  }



























drop_trigger_cleanup:
  sqliteSrcListDelete(pName);
}

/*
** pEList is the SET clause of an UPDATE statement.  Each entry
** in pEList is of the format <id>=<expr>.  If any of the entries

  while( pTriggerStep ){
    int saveNTab = pParse->nTab;
    int saveUseDb = pParse->useDb;
    orconf = (orconfin == OE_Default)?pTriggerStep->orconf:orconfin;
    pParse->trigStack->orconf = orconf;
    pParse->useDb = pTriggerStep->pTrig->iDb;
    if( pParse->useDb==1 ) pParse->useDb = -1;
    switch( pTriggerStep->op ){
      case TK_SELECT: {
	Select * ss = sqliteSelectDup(pTriggerStep->pSelect);		  
	assert(ss);
	assert(ss->pSrc);
	sqliteSelect(pParse, ss, SRT_Discard, 0, 0, 0, 0);
	sqliteSelectDelete(ss);

    create table t1(a,b);
    create view v1 as select * from t1;
    create trigger v1t AFTER update on v1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
  }
} {1 {cannot create AFTER trigger on view: v1}}

# Check for memory leaks in the trigger parser
#
do_test trigger1-2.1 {
  catchsql {
    CREATE TRIGGER r1 AFTER INSERT ON t1 BEGIN
      SELECT * FROM;  -- Syntax error
    END;
  }
} {1 {near ";": syntax error}}
do_test trigger1-2.2 {
  catchsql {
    CREATE TRIGGER r1 AFTER INSERT ON t1 BEGIN
      SELECT * FROM t1;
      SELECT * FROM;  -- Syntax error
    END;
  }
} {1 {near ";": syntax error}}

# Create a trigger that refers to a table that might not exist.
#
do_test trigger1-3.1 {
  execsql {
    CREATE TEMP TABLE t2(x,y);
  }
  catchsql {
    CREATE TRIGGER r1 AFTER INSERT ON t1 BEGIN
      INSERT INTO t2 VALUES(NEW.a,NEW.b);
    END;
  }
} {0 {}}
do_test trigger-3.2 {
  catchsql {
    INSERT INTO t1 VALUES(1,2);
    SELECT * FROM t2;
  }
} {1 {table "t2" is not in database "main"}}
do_test trigger-3.3 {
  db close
  set rc [catch {sqlite db test.db} err]
  if {$rc} {lappend rc $err}
  set rc
} {0}
do_test trigger-3.4 {
  catchsql {
    INSERT INTO t1 VALUES(1,2);
    SELECT * FROM t2;
  }
} {1 {no such table: t2}}
do_test trigger-3.5 {
  catchsql {
    CREATE TEMP TABLE t2(x,y);
    INSERT INTO t1 VALUES(1,2);
    SELECT * FROM t2;
  }
} {1 {table "t2" is not in database "main"}}
do_test trigger-3.6 {
  catchsql {
    DROP TRIGGER r1;
    CREATE TEMP TRIGGER r1 AFTER INSERT ON t1 BEGIN
      INSERT INTO t2 VALUES(NEW.a,NEW.b);
    END;
    INSERT INTO t1 VALUES(1,2);
    SELECT * FROM t2;
  }
} {0 {1 2}}
do_test trigger-3.7 {
  execsql {
    DROP TABLE t2;
    CREATE TABLE t2(x,y);
    SELECT * FROM t2;
  }
} {}
do_test trigger-3.8 {
  execsql {
    INSERT INTO t1 VALUES(3,4);
    SELECT * FROM t1 UNION ALL SELECT * FROM t2;
  }
} {1 2 3 4 3 4}
do_test trigger-3.9 {
  db close
  sqlite db test.db
  execsql {
    INSERT INTO t1 VALUES(5,6);
    SELECT * FROM t1 UNION ALL SELECT * FROM t2;
  }
} {1 2 3 4 5 6 3 4}

finish_test