Annotation of embedaddon/sqlite3/src/trigger.c, revision 1.1.1.1
1.1 misho 1: /*
2: **
3: ** The author disclaims copyright to this source code. In place of
4: ** a legal notice, here is a blessing:
5: **
6: ** May you do good and not evil.
7: ** May you find forgiveness for yourself and forgive others.
8: ** May you share freely, never taking more than you give.
9: **
10: *************************************************************************
11: ** This file contains the implementation for TRIGGERs
12: */
13: #include "sqliteInt.h"
14:
15: #ifndef SQLITE_OMIT_TRIGGER
16: /*
17: ** Delete a linked list of TriggerStep structures.
18: */
19: void sqlite3DeleteTriggerStep(sqlite3 *db, TriggerStep *pTriggerStep){
20: while( pTriggerStep ){
21: TriggerStep * pTmp = pTriggerStep;
22: pTriggerStep = pTriggerStep->pNext;
23:
24: sqlite3ExprDelete(db, pTmp->pWhere);
25: sqlite3ExprListDelete(db, pTmp->pExprList);
26: sqlite3SelectDelete(db, pTmp->pSelect);
27: sqlite3IdListDelete(db, pTmp->pIdList);
28:
29: sqlite3DbFree(db, pTmp);
30: }
31: }
32:
33: /*
34: ** Given table pTab, return a list of all the triggers attached to
35: ** the table. The list is connected by Trigger.pNext pointers.
36: **
37: ** All of the triggers on pTab that are in the same database as pTab
38: ** are already attached to pTab->pTrigger. But there might be additional
39: ** triggers on pTab in the TEMP schema. This routine prepends all
40: ** TEMP triggers on pTab to the beginning of the pTab->pTrigger list
41: ** and returns the combined list.
42: **
43: ** To state it another way: This routine returns a list of all triggers
44: ** that fire off of pTab. The list will include any TEMP triggers on
45: ** pTab as well as the triggers lised in pTab->pTrigger.
46: */
47: Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
48: Schema * const pTmpSchema = pParse->db->aDb[1].pSchema;
49: Trigger *pList = 0; /* List of triggers to return */
50:
51: if( pParse->disableTriggers ){
52: return 0;
53: }
54:
55: if( pTmpSchema!=pTab->pSchema ){
56: HashElem *p;
57: assert( sqlite3SchemaMutexHeld(pParse->db, 0, pTmpSchema) );
58: for(p=sqliteHashFirst(&pTmpSchema->trigHash); p; p=sqliteHashNext(p)){
59: Trigger *pTrig = (Trigger *)sqliteHashData(p);
60: if( pTrig->pTabSchema==pTab->pSchema
61: && 0==sqlite3StrICmp(pTrig->table, pTab->zName)
62: ){
63: pTrig->pNext = (pList ? pList : pTab->pTrigger);
64: pList = pTrig;
65: }
66: }
67: }
68:
69: return (pList ? pList : pTab->pTrigger);
70: }
71:
72: /*
73: ** This is called by the parser when it sees a CREATE TRIGGER statement
74: ** up to the point of the BEGIN before the trigger actions. A Trigger
75: ** structure is generated based on the information available and stored
76: ** in pParse->pNewTrigger. After the trigger actions have been parsed, the
77: ** sqlite3FinishTrigger() function is called to complete the trigger
78: ** construction process.
79: */
80: void sqlite3BeginTrigger(
81: Parse *pParse, /* The parse context of the CREATE TRIGGER statement */
82: Token *pName1, /* The name of the trigger */
83: Token *pName2, /* The name of the trigger */
84: int tr_tm, /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */
85: int op, /* One of TK_INSERT, TK_UPDATE, TK_DELETE */
86: IdList *pColumns, /* column list if this is an UPDATE OF trigger */
87: SrcList *pTableName,/* The name of the table/view the trigger applies to */
88: Expr *pWhen, /* WHEN clause */
89: int isTemp, /* True if the TEMPORARY keyword is present */
90: int noErr /* Suppress errors if the trigger already exists */
91: ){
92: Trigger *pTrigger = 0; /* The new trigger */
93: Table *pTab; /* Table that the trigger fires off of */
94: char *zName = 0; /* Name of the trigger */
95: sqlite3 *db = pParse->db; /* The database connection */
96: int iDb; /* The database to store the trigger in */
97: Token *pName; /* The unqualified db name */
98: DbFixer sFix; /* State vector for the DB fixer */
99: int iTabDb; /* Index of the database holding pTab */
100:
101: assert( pName1!=0 ); /* pName1->z might be NULL, but not pName1 itself */
102: assert( pName2!=0 );
103: assert( op==TK_INSERT || op==TK_UPDATE || op==TK_DELETE );
104: assert( op>0 && op<0xff );
105: if( isTemp ){
106: /* If TEMP was specified, then the trigger name may not be qualified. */
107: if( pName2->n>0 ){
108: sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");
109: goto trigger_cleanup;
110: }
111: iDb = 1;
112: pName = pName1;
113: }else{
114: /* Figure out the db that the the trigger will be created in */
115: iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);
116: if( iDb<0 ){
117: goto trigger_cleanup;
118: }
119: }
120: if( !pTableName || db->mallocFailed ){
121: goto trigger_cleanup;
122: }
123:
124: /* A long-standing parser bug is that this syntax was allowed:
125: **
126: ** CREATE TRIGGER attached.demo AFTER INSERT ON attached.tab ....
127: ** ^^^^^^^^
128: **
129: ** To maintain backwards compatibility, ignore the database
130: ** name on pTableName if we are reparsing our of SQLITE_MASTER.
131: */
132: if( db->init.busy && iDb!=1 ){
133: sqlite3DbFree(db, pTableName->a[0].zDatabase);
134: pTableName->a[0].zDatabase = 0;
135: }
136:
137: /* If the trigger name was unqualified, and the table is a temp table,
138: ** then set iDb to 1 to create the trigger in the temporary database.
139: ** If sqlite3SrcListLookup() returns 0, indicating the table does not
140: ** exist, the error is caught by the block below.
141: */
142: pTab = sqlite3SrcListLookup(pParse, pTableName);
143: if( db->init.busy==0 && pName2->n==0 && pTab
144: && pTab->pSchema==db->aDb[1].pSchema ){
145: iDb = 1;
146: }
147:
148: /* Ensure the table name matches database name and that the table exists */
149: if( db->mallocFailed ) goto trigger_cleanup;
150: assert( pTableName->nSrc==1 );
151: if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) &&
152: sqlite3FixSrcList(&sFix, pTableName) ){
153: goto trigger_cleanup;
154: }
155: pTab = sqlite3SrcListLookup(pParse, pTableName);
156: if( !pTab ){
157: /* The table does not exist. */
158: if( db->init.iDb==1 ){
159: /* Ticket #3810.
160: ** Normally, whenever a table is dropped, all associated triggers are
161: ** dropped too. But if a TEMP trigger is created on a non-TEMP table
162: ** and the table is dropped by a different database connection, the
163: ** trigger is not visible to the database connection that does the
164: ** drop so the trigger cannot be dropped. This results in an
165: ** "orphaned trigger" - a trigger whose associated table is missing.
166: */
167: db->init.orphanTrigger = 1;
168: }
169: goto trigger_cleanup;
170: }
171: if( IsVirtual(pTab) ){
172: sqlite3ErrorMsg(pParse, "cannot create triggers on virtual tables");
173: goto trigger_cleanup;
174: }
175:
176: /* Check that the trigger name is not reserved and that no trigger of the
177: ** specified name exists */
178: zName = sqlite3NameFromToken(db, pName);
179: if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){
180: goto trigger_cleanup;
181: }
182: assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
183: if( sqlite3HashFind(&(db->aDb[iDb].pSchema->trigHash),
184: zName, sqlite3Strlen30(zName)) ){
185: if( !noErr ){
186: sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);
187: }else{
188: assert( !db->init.busy );
189: sqlite3CodeVerifySchema(pParse, iDb);
190: }
191: goto trigger_cleanup;
192: }
193:
194: /* Do not create a trigger on a system table */
195: if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){
196: sqlite3ErrorMsg(pParse, "cannot create trigger on system table");
197: pParse->nErr++;
198: goto trigger_cleanup;
199: }
200:
201: /* INSTEAD of triggers are only for views and views only support INSTEAD
202: ** of triggers.
203: */
204: if( pTab->pSelect && tr_tm!=TK_INSTEAD ){
205: sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",
206: (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);
207: goto trigger_cleanup;
208: }
209: if( !pTab->pSelect && tr_tm==TK_INSTEAD ){
210: sqlite3ErrorMsg(pParse, "cannot create INSTEAD OF"
211: " trigger on table: %S", pTableName, 0);
212: goto trigger_cleanup;
213: }
214: iTabDb = sqlite3SchemaToIndex(db, pTab->pSchema);
215:
216: #ifndef SQLITE_OMIT_AUTHORIZATION
217: {
218: int code = SQLITE_CREATE_TRIGGER;
219: const char *zDb = db->aDb[iTabDb].zName;
220: const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;
221: if( iTabDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;
222: if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){
223: goto trigger_cleanup;
224: }
225: if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(iTabDb),0,zDb)){
226: goto trigger_cleanup;
227: }
228: }
229: #endif
230:
231: /* INSTEAD OF triggers can only appear on views and BEFORE triggers
232: ** cannot appear on views. So we might as well translate every
233: ** INSTEAD OF trigger into a BEFORE trigger. It simplifies code
234: ** elsewhere.
235: */
236: if (tr_tm == TK_INSTEAD){
237: tr_tm = TK_BEFORE;
238: }
239:
240: /* Build the Trigger object */
241: pTrigger = (Trigger*)sqlite3DbMallocZero(db, sizeof(Trigger));
242: if( pTrigger==0 ) goto trigger_cleanup;
243: pTrigger->zName = zName;
244: zName = 0;
245: pTrigger->table = sqlite3DbStrDup(db, pTableName->a[0].zName);
246: pTrigger->pSchema = db->aDb[iDb].pSchema;
247: pTrigger->pTabSchema = pTab->pSchema;
248: pTrigger->op = (u8)op;
249: pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;
250: pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
251: pTrigger->pColumns = sqlite3IdListDup(db, pColumns);
252: assert( pParse->pNewTrigger==0 );
253: pParse->pNewTrigger = pTrigger;
254:
255: trigger_cleanup:
256: sqlite3DbFree(db, zName);
257: sqlite3SrcListDelete(db, pTableName);
258: sqlite3IdListDelete(db, pColumns);
259: sqlite3ExprDelete(db, pWhen);
260: if( !pParse->pNewTrigger ){
261: sqlite3DeleteTrigger(db, pTrigger);
262: }else{
263: assert( pParse->pNewTrigger==pTrigger );
264: }
265: }
266:
267: /*
268: ** This routine is called after all of the trigger actions have been parsed
269: ** in order to complete the process of building the trigger.
270: */
271: void sqlite3FinishTrigger(
272: Parse *pParse, /* Parser context */
273: TriggerStep *pStepList, /* The triggered program */
274: Token *pAll /* Token that describes the complete CREATE TRIGGER */
275: ){
276: Trigger *pTrig = pParse->pNewTrigger; /* Trigger being finished */
277: char *zName; /* Name of trigger */
278: sqlite3 *db = pParse->db; /* The database */
279: DbFixer sFix; /* Fixer object */
280: int iDb; /* Database containing the trigger */
281: Token nameToken; /* Trigger name for error reporting */
282:
283: pParse->pNewTrigger = 0;
284: if( NEVER(pParse->nErr) || !pTrig ) goto triggerfinish_cleanup;
285: zName = pTrig->zName;
286: iDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
287: pTrig->step_list = pStepList;
288: while( pStepList ){
289: pStepList->pTrig = pTrig;
290: pStepList = pStepList->pNext;
291: }
292: nameToken.z = pTrig->zName;
293: nameToken.n = sqlite3Strlen30(nameToken.z);
294: if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", &nameToken)
295: && sqlite3FixTriggerStep(&sFix, pTrig->step_list) ){
296: goto triggerfinish_cleanup;
297: }
298:
299: /* if we are not initializing,
300: ** build the sqlite_master entry
301: */
302: if( !db->init.busy ){
303: Vdbe *v;
304: char *z;
305:
306: /* Make an entry in the sqlite_master table */
307: v = sqlite3GetVdbe(pParse);
308: if( v==0 ) goto triggerfinish_cleanup;
309: sqlite3BeginWriteOperation(pParse, 0, iDb);
310: z = sqlite3DbStrNDup(db, (char*)pAll->z, pAll->n);
311: sqlite3NestedParse(pParse,
312: "INSERT INTO %Q.%s VALUES('trigger',%Q,%Q,0,'CREATE TRIGGER %q')",
313: db->aDb[iDb].zName, SCHEMA_TABLE(iDb), zName,
314: pTrig->table, z);
315: sqlite3DbFree(db, z);
316: sqlite3ChangeCookie(pParse, iDb);
317: sqlite3VdbeAddParseSchemaOp(v, iDb,
318: sqlite3MPrintf(db, "type='trigger' AND name='%q'", zName));
319: }
320:
321: if( db->init.busy ){
322: Trigger *pLink = pTrig;
323: Hash *pHash = &db->aDb[iDb].pSchema->trigHash;
324: assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
325: pTrig = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), pTrig);
326: if( pTrig ){
327: db->mallocFailed = 1;
328: }else if( pLink->pSchema==pLink->pTabSchema ){
329: Table *pTab;
330: int n = sqlite3Strlen30(pLink->table);
331: pTab = sqlite3HashFind(&pLink->pTabSchema->tblHash, pLink->table, n);
332: assert( pTab!=0 );
333: pLink->pNext = pTab->pTrigger;
334: pTab->pTrigger = pLink;
335: }
336: }
337:
338: triggerfinish_cleanup:
339: sqlite3DeleteTrigger(db, pTrig);
340: assert( !pParse->pNewTrigger );
341: sqlite3DeleteTriggerStep(db, pStepList);
342: }
343:
344: /*
345: ** Turn a SELECT statement (that the pSelect parameter points to) into
346: ** a trigger step. Return a pointer to a TriggerStep structure.
347: **
348: ** The parser calls this routine when it finds a SELECT statement in
349: ** body of a TRIGGER.
350: */
351: TriggerStep *sqlite3TriggerSelectStep(sqlite3 *db, Select *pSelect){
352: TriggerStep *pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep));
353: if( pTriggerStep==0 ) {
354: sqlite3SelectDelete(db, pSelect);
355: return 0;
356: }
357: pTriggerStep->op = TK_SELECT;
358: pTriggerStep->pSelect = pSelect;
359: pTriggerStep->orconf = OE_Default;
360: return pTriggerStep;
361: }
362:
363: /*
364: ** Allocate space to hold a new trigger step. The allocated space
365: ** holds both the TriggerStep object and the TriggerStep.target.z string.
366: **
367: ** If an OOM error occurs, NULL is returned and db->mallocFailed is set.
368: */
369: static TriggerStep *triggerStepAllocate(
370: sqlite3 *db, /* Database connection */
371: u8 op, /* Trigger opcode */
372: Token *pName /* The target name */
373: ){
374: TriggerStep *pTriggerStep;
375:
376: pTriggerStep = sqlite3DbMallocZero(db, sizeof(TriggerStep) + pName->n);
377: if( pTriggerStep ){
378: char *z = (char*)&pTriggerStep[1];
379: memcpy(z, pName->z, pName->n);
380: pTriggerStep->target.z = z;
381: pTriggerStep->target.n = pName->n;
382: pTriggerStep->op = op;
383: }
384: return pTriggerStep;
385: }
386:
387: /*
388: ** Build a trigger step out of an INSERT statement. Return a pointer
389: ** to the new trigger step.
390: **
391: ** The parser calls this routine when it sees an INSERT inside the
392: ** body of a trigger.
393: */
394: TriggerStep *sqlite3TriggerInsertStep(
395: sqlite3 *db, /* The database connection */
396: Token *pTableName, /* Name of the table into which we insert */
397: IdList *pColumn, /* List of columns in pTableName to insert into */
398: ExprList *pEList, /* The VALUE clause: a list of values to be inserted */
399: Select *pSelect, /* A SELECT statement that supplies values */
400: u8 orconf /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */
401: ){
402: TriggerStep *pTriggerStep;
403:
404: assert(pEList == 0 || pSelect == 0);
405: assert(pEList != 0 || pSelect != 0 || db->mallocFailed);
406:
407: pTriggerStep = triggerStepAllocate(db, TK_INSERT, pTableName);
408: if( pTriggerStep ){
409: pTriggerStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
410: pTriggerStep->pIdList = pColumn;
411: pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
412: pTriggerStep->orconf = orconf;
413: }else{
414: sqlite3IdListDelete(db, pColumn);
415: }
416: sqlite3ExprListDelete(db, pEList);
417: sqlite3SelectDelete(db, pSelect);
418:
419: return pTriggerStep;
420: }
421:
422: /*
423: ** Construct a trigger step that implements an UPDATE statement and return
424: ** a pointer to that trigger step. The parser calls this routine when it
425: ** sees an UPDATE statement inside the body of a CREATE TRIGGER.
426: */
427: TriggerStep *sqlite3TriggerUpdateStep(
428: sqlite3 *db, /* The database connection */
429: Token *pTableName, /* Name of the table to be updated */
430: ExprList *pEList, /* The SET clause: list of column and new values */
431: Expr *pWhere, /* The WHERE clause */
432: u8 orconf /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */
433: ){
434: TriggerStep *pTriggerStep;
435:
436: pTriggerStep = triggerStepAllocate(db, TK_UPDATE, pTableName);
437: if( pTriggerStep ){
438: pTriggerStep->pExprList = sqlite3ExprListDup(db, pEList, EXPRDUP_REDUCE);
439: pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
440: pTriggerStep->orconf = orconf;
441: }
442: sqlite3ExprListDelete(db, pEList);
443: sqlite3ExprDelete(db, pWhere);
444: return pTriggerStep;
445: }
446:
447: /*
448: ** Construct a trigger step that implements a DELETE statement and return
449: ** a pointer to that trigger step. The parser calls this routine when it
450: ** sees a DELETE statement inside the body of a CREATE TRIGGER.
451: */
452: TriggerStep *sqlite3TriggerDeleteStep(
453: sqlite3 *db, /* Database connection */
454: Token *pTableName, /* The table from which rows are deleted */
455: Expr *pWhere /* The WHERE clause */
456: ){
457: TriggerStep *pTriggerStep;
458:
459: pTriggerStep = triggerStepAllocate(db, TK_DELETE, pTableName);
460: if( pTriggerStep ){
461: pTriggerStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
462: pTriggerStep->orconf = OE_Default;
463: }
464: sqlite3ExprDelete(db, pWhere);
465: return pTriggerStep;
466: }
467:
468: /*
469: ** Recursively delete a Trigger structure
470: */
471: void sqlite3DeleteTrigger(sqlite3 *db, Trigger *pTrigger){
472: if( pTrigger==0 ) return;
473: sqlite3DeleteTriggerStep(db, pTrigger->step_list);
474: sqlite3DbFree(db, pTrigger->zName);
475: sqlite3DbFree(db, pTrigger->table);
476: sqlite3ExprDelete(db, pTrigger->pWhen);
477: sqlite3IdListDelete(db, pTrigger->pColumns);
478: sqlite3DbFree(db, pTrigger);
479: }
480:
481: /*
482: ** This function is called to drop a trigger from the database schema.
483: **
484: ** This may be called directly from the parser and therefore identifies
485: ** the trigger by name. The sqlite3DropTriggerPtr() routine does the
486: ** same job as this routine except it takes a pointer to the trigger
487: ** instead of the trigger name.
488: **/
489: void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
490: Trigger *pTrigger = 0;
491: int i;
492: const char *zDb;
493: const char *zName;
494: int nName;
495: sqlite3 *db = pParse->db;
496:
497: if( db->mallocFailed ) goto drop_trigger_cleanup;
498: if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
499: goto drop_trigger_cleanup;
500: }
501:
502: assert( pName->nSrc==1 );
503: zDb = pName->a[0].zDatabase;
504: zName = pName->a[0].zName;
505: nName = sqlite3Strlen30(zName);
506: assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
507: for(i=OMIT_TEMPDB; i<db->nDb; i++){
508: int j = (i<2) ? i^1 : i; /* Search TEMP before MAIN */
509: if( zDb && sqlite3StrICmp(db->aDb[j].zName, zDb) ) continue;
510: assert( sqlite3SchemaMutexHeld(db, j, 0) );
511: pTrigger = sqlite3HashFind(&(db->aDb[j].pSchema->trigHash), zName, nName);
512: if( pTrigger ) break;
513: }
514: if( !pTrigger ){
515: if( !noErr ){
516: sqlite3ErrorMsg(pParse, "no such trigger: %S", pName, 0);
517: }else{
518: sqlite3CodeVerifyNamedSchema(pParse, zDb);
519: }
520: pParse->checkSchema = 1;
521: goto drop_trigger_cleanup;
522: }
523: sqlite3DropTriggerPtr(pParse, pTrigger);
524:
525: drop_trigger_cleanup:
526: sqlite3SrcListDelete(db, pName);
527: }
528:
529: /*
530: ** Return a pointer to the Table structure for the table that a trigger
531: ** is set on.
532: */
533: static Table *tableOfTrigger(Trigger *pTrigger){
534: int n = sqlite3Strlen30(pTrigger->table);
535: return sqlite3HashFind(&pTrigger->pTabSchema->tblHash, pTrigger->table, n);
536: }
537:
538:
539: /*
540: ** Drop a trigger given a pointer to that trigger.
541: */
542: void sqlite3DropTriggerPtr(Parse *pParse, Trigger *pTrigger){
543: Table *pTable;
544: Vdbe *v;
545: sqlite3 *db = pParse->db;
546: int iDb;
547:
548: iDb = sqlite3SchemaToIndex(pParse->db, pTrigger->pSchema);
549: assert( iDb>=0 && iDb<db->nDb );
550: pTable = tableOfTrigger(pTrigger);
551: assert( pTable );
552: assert( pTable->pSchema==pTrigger->pSchema || iDb==1 );
553: #ifndef SQLITE_OMIT_AUTHORIZATION
554: {
555: int code = SQLITE_DROP_TRIGGER;
556: const char *zDb = db->aDb[iDb].zName;
557: const char *zTab = SCHEMA_TABLE(iDb);
558: if( iDb==1 ) code = SQLITE_DROP_TEMP_TRIGGER;
559: if( sqlite3AuthCheck(pParse, code, pTrigger->zName, pTable->zName, zDb) ||
560: sqlite3AuthCheck(pParse, SQLITE_DELETE, zTab, 0, zDb) ){
561: return;
562: }
563: }
564: #endif
565:
566: /* Generate code to destroy the database record of the trigger.
567: */
568: assert( pTable!=0 );
569: if( (v = sqlite3GetVdbe(pParse))!=0 ){
570: int base;
571: static const VdbeOpList dropTrigger[] = {
572: { OP_Rewind, 0, ADDR(9), 0},
573: { OP_String8, 0, 1, 0}, /* 1 */
574: { OP_Column, 0, 1, 2},
575: { OP_Ne, 2, ADDR(8), 1},
576: { OP_String8, 0, 1, 0}, /* 4: "trigger" */
577: { OP_Column, 0, 0, 2},
578: { OP_Ne, 2, ADDR(8), 1},
579: { OP_Delete, 0, 0, 0},
580: { OP_Next, 0, ADDR(1), 0}, /* 8 */
581: };
582:
583: sqlite3BeginWriteOperation(pParse, 0, iDb);
584: sqlite3OpenMasterTable(pParse, iDb);
585: base = sqlite3VdbeAddOpList(v, ArraySize(dropTrigger), dropTrigger);
586: sqlite3VdbeChangeP4(v, base+1, pTrigger->zName, P4_TRANSIENT);
587: sqlite3VdbeChangeP4(v, base+4, "trigger", P4_STATIC);
588: sqlite3ChangeCookie(pParse, iDb);
589: sqlite3VdbeAddOp2(v, OP_Close, 0, 0);
590: sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);
591: if( pParse->nMem<3 ){
592: pParse->nMem = 3;
593: }
594: }
595: }
596:
597: /*
598: ** Remove a trigger from the hash tables of the sqlite* pointer.
599: */
600: void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){
601: Trigger *pTrigger;
602: Hash *pHash;
603:
604: assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
605: pHash = &(db->aDb[iDb].pSchema->trigHash);
606: pTrigger = sqlite3HashInsert(pHash, zName, sqlite3Strlen30(zName), 0);
607: if( ALWAYS(pTrigger) ){
608: if( pTrigger->pSchema==pTrigger->pTabSchema ){
609: Table *pTab = tableOfTrigger(pTrigger);
610: Trigger **pp;
611: for(pp=&pTab->pTrigger; *pp!=pTrigger; pp=&((*pp)->pNext));
612: *pp = (*pp)->pNext;
613: }
614: sqlite3DeleteTrigger(db, pTrigger);
615: db->flags |= SQLITE_InternChanges;
616: }
617: }
618:
619: /*
620: ** pEList is the SET clause of an UPDATE statement. Each entry
621: ** in pEList is of the format <id>=<expr>. If any of the entries
622: ** in pEList have an <id> which matches an identifier in pIdList,
623: ** then return TRUE. If pIdList==NULL, then it is considered a
624: ** wildcard that matches anything. Likewise if pEList==NULL then
625: ** it matches anything so always return true. Return false only
626: ** if there is no match.
627: */
628: static int checkColumnOverlap(IdList *pIdList, ExprList *pEList){
629: int e;
630: if( pIdList==0 || NEVER(pEList==0) ) return 1;
631: for(e=0; e<pEList->nExpr; e++){
632: if( sqlite3IdListIndex(pIdList, pEList->a[e].zName)>=0 ) return 1;
633: }
634: return 0;
635: }
636:
637: /*
638: ** Return a list of all triggers on table pTab if there exists at least
639: ** one trigger that must be fired when an operation of type 'op' is
640: ** performed on the table, and, if that operation is an UPDATE, if at
641: ** least one of the columns in pChanges is being modified.
642: */
643: Trigger *sqlite3TriggersExist(
644: Parse *pParse, /* Parse context */
645: Table *pTab, /* The table the contains the triggers */
646: int op, /* one of TK_DELETE, TK_INSERT, TK_UPDATE */
647: ExprList *pChanges, /* Columns that change in an UPDATE statement */
648: int *pMask /* OUT: Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
649: ){
650: int mask = 0;
651: Trigger *pList = 0;
652: Trigger *p;
653:
654: if( (pParse->db->flags & SQLITE_EnableTrigger)!=0 ){
655: pList = sqlite3TriggerList(pParse, pTab);
656: }
657: assert( pList==0 || IsVirtual(pTab)==0 );
658: for(p=pList; p; p=p->pNext){
659: if( p->op==op && checkColumnOverlap(p->pColumns, pChanges) ){
660: mask |= p->tr_tm;
661: }
662: }
663: if( pMask ){
664: *pMask = mask;
665: }
666: return (mask ? pList : 0);
667: }
668:
669: /*
670: ** Convert the pStep->target token into a SrcList and return a pointer
671: ** to that SrcList.
672: **
673: ** This routine adds a specific database name, if needed, to the target when
674: ** forming the SrcList. This prevents a trigger in one database from
675: ** referring to a target in another database. An exception is when the
676: ** trigger is in TEMP in which case it can refer to any other database it
677: ** wants.
678: */
679: static SrcList *targetSrcList(
680: Parse *pParse, /* The parsing context */
681: TriggerStep *pStep /* The trigger containing the target token */
682: ){
683: int iDb; /* Index of the database to use */
684: SrcList *pSrc; /* SrcList to be returned */
685:
686: pSrc = sqlite3SrcListAppend(pParse->db, 0, &pStep->target, 0);
687: if( pSrc ){
688: assert( pSrc->nSrc>0 );
689: assert( pSrc->a!=0 );
690: iDb = sqlite3SchemaToIndex(pParse->db, pStep->pTrig->pSchema);
691: if( iDb==0 || iDb>=2 ){
692: sqlite3 *db = pParse->db;
693: assert( iDb<pParse->db->nDb );
694: pSrc->a[pSrc->nSrc-1].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zName);
695: }
696: }
697: return pSrc;
698: }
699:
700: /*
701: ** Generate VDBE code for the statements inside the body of a single
702: ** trigger.
703: */
704: static int codeTriggerProgram(
705: Parse *pParse, /* The parser context */
706: TriggerStep *pStepList, /* List of statements inside the trigger body */
707: int orconf /* Conflict algorithm. (OE_Abort, etc) */
708: ){
709: TriggerStep *pStep;
710: Vdbe *v = pParse->pVdbe;
711: sqlite3 *db = pParse->db;
712:
713: assert( pParse->pTriggerTab && pParse->pToplevel );
714: assert( pStepList );
715: assert( v!=0 );
716: for(pStep=pStepList; pStep; pStep=pStep->pNext){
717: /* Figure out the ON CONFLICT policy that will be used for this step
718: ** of the trigger program. If the statement that caused this trigger
719: ** to fire had an explicit ON CONFLICT, then use it. Otherwise, use
720: ** the ON CONFLICT policy that was specified as part of the trigger
721: ** step statement. Example:
722: **
723: ** CREATE TRIGGER AFTER INSERT ON t1 BEGIN;
724: ** INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
725: ** END;
726: **
727: ** INSERT INTO t1 ... ; -- insert into t2 uses REPLACE policy
728: ** INSERT OR IGNORE INTO t1 ... ; -- insert into t2 uses IGNORE policy
729: */
730: pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;
731:
732: switch( pStep->op ){
733: case TK_UPDATE: {
734: sqlite3Update(pParse,
735: targetSrcList(pParse, pStep),
736: sqlite3ExprListDup(db, pStep->pExprList, 0),
737: sqlite3ExprDup(db, pStep->pWhere, 0),
738: pParse->eOrconf
739: );
740: break;
741: }
742: case TK_INSERT: {
743: sqlite3Insert(pParse,
744: targetSrcList(pParse, pStep),
745: sqlite3ExprListDup(db, pStep->pExprList, 0),
746: sqlite3SelectDup(db, pStep->pSelect, 0),
747: sqlite3IdListDup(db, pStep->pIdList),
748: pParse->eOrconf
749: );
750: break;
751: }
752: case TK_DELETE: {
753: sqlite3DeleteFrom(pParse,
754: targetSrcList(pParse, pStep),
755: sqlite3ExprDup(db, pStep->pWhere, 0)
756: );
757: break;
758: }
759: default: assert( pStep->op==TK_SELECT ); {
760: SelectDest sDest;
761: Select *pSelect = sqlite3SelectDup(db, pStep->pSelect, 0);
762: sqlite3SelectDestInit(&sDest, SRT_Discard, 0);
763: sqlite3Select(pParse, pSelect, &sDest);
764: sqlite3SelectDelete(db, pSelect);
765: break;
766: }
767: }
768: if( pStep->op!=TK_SELECT ){
769: sqlite3VdbeAddOp0(v, OP_ResetCount);
770: }
771: }
772:
773: return 0;
774: }
775:
776: #ifdef SQLITE_DEBUG
777: /*
778: ** This function is used to add VdbeComment() annotations to a VDBE
779: ** program. It is not used in production code, only for debugging.
780: */
781: static const char *onErrorText(int onError){
782: switch( onError ){
783: case OE_Abort: return "abort";
784: case OE_Rollback: return "rollback";
785: case OE_Fail: return "fail";
786: case OE_Replace: return "replace";
787: case OE_Ignore: return "ignore";
788: case OE_Default: return "default";
789: }
790: return "n/a";
791: }
792: #endif
793:
794: /*
795: ** Parse context structure pFrom has just been used to create a sub-vdbe
796: ** (trigger program). If an error has occurred, transfer error information
797: ** from pFrom to pTo.
798: */
799: static void transferParseError(Parse *pTo, Parse *pFrom){
800: assert( pFrom->zErrMsg==0 || pFrom->nErr );
801: assert( pTo->zErrMsg==0 || pTo->nErr );
802: if( pTo->nErr==0 ){
803: pTo->zErrMsg = pFrom->zErrMsg;
804: pTo->nErr = pFrom->nErr;
805: }else{
806: sqlite3DbFree(pFrom->db, pFrom->zErrMsg);
807: }
808: }
809:
810: /*
811: ** Create and populate a new TriggerPrg object with a sub-program
812: ** implementing trigger pTrigger with ON CONFLICT policy orconf.
813: */
814: static TriggerPrg *codeRowTrigger(
815: Parse *pParse, /* Current parse context */
816: Trigger *pTrigger, /* Trigger to code */
817: Table *pTab, /* The table pTrigger is attached to */
818: int orconf /* ON CONFLICT policy to code trigger program with */
819: ){
820: Parse *pTop = sqlite3ParseToplevel(pParse);
821: sqlite3 *db = pParse->db; /* Database handle */
822: TriggerPrg *pPrg; /* Value to return */
823: Expr *pWhen = 0; /* Duplicate of trigger WHEN expression */
824: Vdbe *v; /* Temporary VM */
825: NameContext sNC; /* Name context for sub-vdbe */
826: SubProgram *pProgram = 0; /* Sub-vdbe for trigger program */
827: Parse *pSubParse; /* Parse context for sub-vdbe */
828: int iEndTrigger = 0; /* Label to jump to if WHEN is false */
829:
830: assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
831: assert( pTop->pVdbe );
832:
833: /* Allocate the TriggerPrg and SubProgram objects. To ensure that they
834: ** are freed if an error occurs, link them into the Parse.pTriggerPrg
835: ** list of the top-level Parse object sooner rather than later. */
836: pPrg = sqlite3DbMallocZero(db, sizeof(TriggerPrg));
837: if( !pPrg ) return 0;
838: pPrg->pNext = pTop->pTriggerPrg;
839: pTop->pTriggerPrg = pPrg;
840: pPrg->pProgram = pProgram = sqlite3DbMallocZero(db, sizeof(SubProgram));
841: if( !pProgram ) return 0;
842: sqlite3VdbeLinkSubProgram(pTop->pVdbe, pProgram);
843: pPrg->pTrigger = pTrigger;
844: pPrg->orconf = orconf;
845: pPrg->aColmask[0] = 0xffffffff;
846: pPrg->aColmask[1] = 0xffffffff;
847:
848: /* Allocate and populate a new Parse context to use for coding the
849: ** trigger sub-program. */
850: pSubParse = sqlite3StackAllocZero(db, sizeof(Parse));
851: if( !pSubParse ) return 0;
852: memset(&sNC, 0, sizeof(sNC));
853: sNC.pParse = pSubParse;
854: pSubParse->db = db;
855: pSubParse->pTriggerTab = pTab;
856: pSubParse->pToplevel = pTop;
857: pSubParse->zAuthContext = pTrigger->zName;
858: pSubParse->eTriggerOp = pTrigger->op;
859: pSubParse->nQueryLoop = pParse->nQueryLoop;
860:
861: v = sqlite3GetVdbe(pSubParse);
862: if( v ){
863: VdbeComment((v, "Start: %s.%s (%s %s%s%s ON %s)",
864: pTrigger->zName, onErrorText(orconf),
865: (pTrigger->tr_tm==TRIGGER_BEFORE ? "BEFORE" : "AFTER"),
866: (pTrigger->op==TK_UPDATE ? "UPDATE" : ""),
867: (pTrigger->op==TK_INSERT ? "INSERT" : ""),
868: (pTrigger->op==TK_DELETE ? "DELETE" : ""),
869: pTab->zName
870: ));
871: #ifndef SQLITE_OMIT_TRACE
872: sqlite3VdbeChangeP4(v, -1,
873: sqlite3MPrintf(db, "-- TRIGGER %s", pTrigger->zName), P4_DYNAMIC
874: );
875: #endif
876:
877: /* If one was specified, code the WHEN clause. If it evaluates to false
878: ** (or NULL) the sub-vdbe is immediately halted by jumping to the
879: ** OP_Halt inserted at the end of the program. */
880: if( pTrigger->pWhen ){
881: pWhen = sqlite3ExprDup(db, pTrigger->pWhen, 0);
882: if( SQLITE_OK==sqlite3ResolveExprNames(&sNC, pWhen)
883: && db->mallocFailed==0
884: ){
885: iEndTrigger = sqlite3VdbeMakeLabel(v);
886: sqlite3ExprIfFalse(pSubParse, pWhen, iEndTrigger, SQLITE_JUMPIFNULL);
887: }
888: sqlite3ExprDelete(db, pWhen);
889: }
890:
891: /* Code the trigger program into the sub-vdbe. */
892: codeTriggerProgram(pSubParse, pTrigger->step_list, orconf);
893:
894: /* Insert an OP_Halt at the end of the sub-program. */
895: if( iEndTrigger ){
896: sqlite3VdbeResolveLabel(v, iEndTrigger);
897: }
898: sqlite3VdbeAddOp0(v, OP_Halt);
899: VdbeComment((v, "End: %s.%s", pTrigger->zName, onErrorText(orconf)));
900:
901: transferParseError(pParse, pSubParse);
902: if( db->mallocFailed==0 ){
903: pProgram->aOp = sqlite3VdbeTakeOpArray(v, &pProgram->nOp, &pTop->nMaxArg);
904: }
905: pProgram->nMem = pSubParse->nMem;
906: pProgram->nCsr = pSubParse->nTab;
907: pProgram->nOnce = pSubParse->nOnce;
908: pProgram->token = (void *)pTrigger;
909: pPrg->aColmask[0] = pSubParse->oldmask;
910: pPrg->aColmask[1] = pSubParse->newmask;
911: sqlite3VdbeDelete(v);
912: }
913:
914: assert( !pSubParse->pAinc && !pSubParse->pZombieTab );
915: assert( !pSubParse->pTriggerPrg && !pSubParse->nMaxArg );
916: sqlite3StackFree(db, pSubParse);
917:
918: return pPrg;
919: }
920:
921: /*
922: ** Return a pointer to a TriggerPrg object containing the sub-program for
923: ** trigger pTrigger with default ON CONFLICT algorithm orconf. If no such
924: ** TriggerPrg object exists, a new object is allocated and populated before
925: ** being returned.
926: */
927: static TriggerPrg *getRowTrigger(
928: Parse *pParse, /* Current parse context */
929: Trigger *pTrigger, /* Trigger to code */
930: Table *pTab, /* The table trigger pTrigger is attached to */
931: int orconf /* ON CONFLICT algorithm. */
932: ){
933: Parse *pRoot = sqlite3ParseToplevel(pParse);
934: TriggerPrg *pPrg;
935:
936: assert( pTrigger->zName==0 || pTab==tableOfTrigger(pTrigger) );
937:
938: /* It may be that this trigger has already been coded (or is in the
939: ** process of being coded). If this is the case, then an entry with
940: ** a matching TriggerPrg.pTrigger field will be present somewhere
941: ** in the Parse.pTriggerPrg list. Search for such an entry. */
942: for(pPrg=pRoot->pTriggerPrg;
943: pPrg && (pPrg->pTrigger!=pTrigger || pPrg->orconf!=orconf);
944: pPrg=pPrg->pNext
945: );
946:
947: /* If an existing TriggerPrg could not be located, create a new one. */
948: if( !pPrg ){
949: pPrg = codeRowTrigger(pParse, pTrigger, pTab, orconf);
950: }
951:
952: return pPrg;
953: }
954:
955: /*
956: ** Generate code for the trigger program associated with trigger p on
957: ** table pTab. The reg, orconf and ignoreJump parameters passed to this
958: ** function are the same as those described in the header function for
959: ** sqlite3CodeRowTrigger()
960: */
961: void sqlite3CodeRowTriggerDirect(
962: Parse *pParse, /* Parse context */
963: Trigger *p, /* Trigger to code */
964: Table *pTab, /* The table to code triggers from */
965: int reg, /* Reg array containing OLD.* and NEW.* values */
966: int orconf, /* ON CONFLICT policy */
967: int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */
968: ){
969: Vdbe *v = sqlite3GetVdbe(pParse); /* Main VM */
970: TriggerPrg *pPrg;
971: pPrg = getRowTrigger(pParse, p, pTab, orconf);
972: assert( pPrg || pParse->nErr || pParse->db->mallocFailed );
973:
974: /* Code the OP_Program opcode in the parent VDBE. P4 of the OP_Program
975: ** is a pointer to the sub-vdbe containing the trigger program. */
976: if( pPrg ){
977: int bRecursive = (p->zName && 0==(pParse->db->flags&SQLITE_RecTriggers));
978:
979: sqlite3VdbeAddOp3(v, OP_Program, reg, ignoreJump, ++pParse->nMem);
980: sqlite3VdbeChangeP4(v, -1, (const char *)pPrg->pProgram, P4_SUBPROGRAM);
981: VdbeComment(
982: (v, "Call: %s.%s", (p->zName?p->zName:"fkey"), onErrorText(orconf)));
983:
984: /* Set the P5 operand of the OP_Program instruction to non-zero if
985: ** recursive invocation of this trigger program is disallowed. Recursive
986: ** invocation is disallowed if (a) the sub-program is really a trigger,
987: ** not a foreign key action, and (b) the flag to enable recursive triggers
988: ** is clear. */
989: sqlite3VdbeChangeP5(v, (u8)bRecursive);
990: }
991: }
992:
993: /*
994: ** This is called to code the required FOR EACH ROW triggers for an operation
995: ** on table pTab. The operation to code triggers for (INSERT, UPDATE or DELETE)
996: ** is given by the op paramater. The tr_tm parameter determines whether the
997: ** BEFORE or AFTER triggers are coded. If the operation is an UPDATE, then
998: ** parameter pChanges is passed the list of columns being modified.
999: **
1000: ** If there are no triggers that fire at the specified time for the specified
1001: ** operation on pTab, this function is a no-op.
1002: **
1003: ** The reg argument is the address of the first in an array of registers
1004: ** that contain the values substituted for the new.* and old.* references
1005: ** in the trigger program. If N is the number of columns in table pTab
1006: ** (a copy of pTab->nCol), then registers are populated as follows:
1007: **
1008: ** Register Contains
1009: ** ------------------------------------------------------
1010: ** reg+0 OLD.rowid
1011: ** reg+1 OLD.* value of left-most column of pTab
1012: ** ... ...
1013: ** reg+N OLD.* value of right-most column of pTab
1014: ** reg+N+1 NEW.rowid
1015: ** reg+N+2 OLD.* value of left-most column of pTab
1016: ** ... ...
1017: ** reg+N+N+1 NEW.* value of right-most column of pTab
1018: **
1019: ** For ON DELETE triggers, the registers containing the NEW.* values will
1020: ** never be accessed by the trigger program, so they are not allocated or
1021: ** populated by the caller (there is no data to populate them with anyway).
1022: ** Similarly, for ON INSERT triggers the values stored in the OLD.* registers
1023: ** are never accessed, and so are not allocated by the caller. So, for an
1024: ** ON INSERT trigger, the value passed to this function as parameter reg
1025: ** is not a readable register, although registers (reg+N) through
1026: ** (reg+N+N+1) are.
1027: **
1028: ** Parameter orconf is the default conflict resolution algorithm for the
1029: ** trigger program to use (REPLACE, IGNORE etc.). Parameter ignoreJump
1030: ** is the instruction that control should jump to if a trigger program
1031: ** raises an IGNORE exception.
1032: */
1033: void sqlite3CodeRowTrigger(
1034: Parse *pParse, /* Parse context */
1035: Trigger *pTrigger, /* List of triggers on table pTab */
1036: int op, /* One of TK_UPDATE, TK_INSERT, TK_DELETE */
1037: ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
1038: int tr_tm, /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
1039: Table *pTab, /* The table to code triggers from */
1040: int reg, /* The first in an array of registers (see above) */
1041: int orconf, /* ON CONFLICT policy */
1042: int ignoreJump /* Instruction to jump to for RAISE(IGNORE) */
1043: ){
1044: Trigger *p; /* Used to iterate through pTrigger list */
1045:
1046: assert( op==TK_UPDATE || op==TK_INSERT || op==TK_DELETE );
1047: assert( tr_tm==TRIGGER_BEFORE || tr_tm==TRIGGER_AFTER );
1048: assert( (op==TK_UPDATE)==(pChanges!=0) );
1049:
1050: for(p=pTrigger; p; p=p->pNext){
1051:
1052: /* Sanity checking: The schema for the trigger and for the table are
1053: ** always defined. The trigger must be in the same schema as the table
1054: ** or else it must be a TEMP trigger. */
1055: assert( p->pSchema!=0 );
1056: assert( p->pTabSchema!=0 );
1057: assert( p->pSchema==p->pTabSchema
1058: || p->pSchema==pParse->db->aDb[1].pSchema );
1059:
1060: /* Determine whether we should code this trigger */
1061: if( p->op==op
1062: && p->tr_tm==tr_tm
1063: && checkColumnOverlap(p->pColumns, pChanges)
1064: ){
1065: sqlite3CodeRowTriggerDirect(pParse, p, pTab, reg, orconf, ignoreJump);
1066: }
1067: }
1068: }
1069:
1070: /*
1071: ** Triggers may access values stored in the old.* or new.* pseudo-table.
1072: ** This function returns a 32-bit bitmask indicating which columns of the
1073: ** old.* or new.* tables actually are used by triggers. This information
1074: ** may be used by the caller, for example, to avoid having to load the entire
1075: ** old.* record into memory when executing an UPDATE or DELETE command.
1076: **
1077: ** Bit 0 of the returned mask is set if the left-most column of the
1078: ** table may be accessed using an [old|new].<col> reference. Bit 1 is set if
1079: ** the second leftmost column value is required, and so on. If there
1080: ** are more than 32 columns in the table, and at least one of the columns
1081: ** with an index greater than 32 may be accessed, 0xffffffff is returned.
1082: **
1083: ** It is not possible to determine if the old.rowid or new.rowid column is
1084: ** accessed by triggers. The caller must always assume that it is.
1085: **
1086: ** Parameter isNew must be either 1 or 0. If it is 0, then the mask returned
1087: ** applies to the old.* table. If 1, the new.* table.
1088: **
1089: ** Parameter tr_tm must be a mask with one or both of the TRIGGER_BEFORE
1090: ** and TRIGGER_AFTER bits set. Values accessed by BEFORE triggers are only
1091: ** included in the returned mask if the TRIGGER_BEFORE bit is set in the
1092: ** tr_tm parameter. Similarly, values accessed by AFTER triggers are only
1093: ** included in the returned mask if the TRIGGER_AFTER bit is set in tr_tm.
1094: */
1095: u32 sqlite3TriggerColmask(
1096: Parse *pParse, /* Parse context */
1097: Trigger *pTrigger, /* List of triggers on table pTab */
1098: ExprList *pChanges, /* Changes list for any UPDATE OF triggers */
1099: int isNew, /* 1 for new.* ref mask, 0 for old.* ref mask */
1100: int tr_tm, /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
1101: Table *pTab, /* The table to code triggers from */
1102: int orconf /* Default ON CONFLICT policy for trigger steps */
1103: ){
1104: const int op = pChanges ? TK_UPDATE : TK_DELETE;
1105: u32 mask = 0;
1106: Trigger *p;
1107:
1108: assert( isNew==1 || isNew==0 );
1109: for(p=pTrigger; p; p=p->pNext){
1110: if( p->op==op && (tr_tm&p->tr_tm)
1111: && checkColumnOverlap(p->pColumns,pChanges)
1112: ){
1113: TriggerPrg *pPrg;
1114: pPrg = getRowTrigger(pParse, p, pTab, orconf);
1115: if( pPrg ){
1116: mask |= pPrg->aColmask[isNew];
1117: }
1118: }
1119: }
1120:
1121: return mask;
1122: }
1123:
1124: #endif /* !defined(SQLITE_OMIT_TRIGGER) */
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