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Side by Side Diff: third_party/sqlite/sqlite-src-3100200/src/alter.c

Issue 2846743003: [sql] Remove SQLite 3.10.2 reference directory. (Closed)
Patch Set: Created 3 years, 7 months ago
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1 /*
2 ** 2005 February 15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This file contains C code routines that used to generate VDBE code
13 ** that implements the ALTER TABLE command.
14 */
15 #include "sqliteInt.h"
16
17 /*
18 ** The code in this file only exists if we are not omitting the
19 ** ALTER TABLE logic from the build.
20 */
21 #ifndef SQLITE_OMIT_ALTERTABLE
22
23
24 /*
25 ** This function is used by SQL generated to implement the
26 ** ALTER TABLE command. The first argument is the text of a CREATE TABLE or
27 ** CREATE INDEX command. The second is a table name. The table name in
28 ** the CREATE TABLE or CREATE INDEX statement is replaced with the third
29 ** argument and the result returned. Examples:
30 **
31 ** sqlite_rename_table('CREATE TABLE abc(a, b, c)', 'def')
32 ** -> 'CREATE TABLE def(a, b, c)'
33 **
34 ** sqlite_rename_table('CREATE INDEX i ON abc(a)', 'def')
35 ** -> 'CREATE INDEX i ON def(a, b, c)'
36 */
37 static void renameTableFunc(
38 sqlite3_context *context,
39 int NotUsed,
40 sqlite3_value **argv
41 ){
42 unsigned char const *zSql = sqlite3_value_text(argv[0]);
43 unsigned char const *zTableName = sqlite3_value_text(argv[1]);
44
45 int token;
46 Token tname;
47 unsigned char const *zCsr = zSql;
48 int len = 0;
49 char *zRet;
50
51 sqlite3 *db = sqlite3_context_db_handle(context);
52
53 UNUSED_PARAMETER(NotUsed);
54
55 /* The principle used to locate the table name in the CREATE TABLE
56 ** statement is that the table name is the first non-space token that
57 ** is immediately followed by a TK_LP or TK_USING token.
58 */
59 if( zSql ){
60 do {
61 if( !*zCsr ){
62 /* Ran out of input before finding an opening bracket. Return NULL. */
63 return;
64 }
65
66 /* Store the token that zCsr points to in tname. */
67 tname.z = (char*)zCsr;
68 tname.n = len;
69
70 /* Advance zCsr to the next token. Store that token type in 'token',
71 ** and its length in 'len' (to be used next iteration of this loop).
72 */
73 do {
74 zCsr += len;
75 len = sqlite3GetToken(zCsr, &token);
76 } while( token==TK_SPACE );
77 assert( len>0 );
78 } while( token!=TK_LP && token!=TK_USING );
79
80 zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", (int)(((u8*)tname.z) - zSql),
81 zSql, zTableName, tname.z+tname.n);
82 sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
83 }
84 }
85
86 /*
87 ** This C function implements an SQL user function that is used by SQL code
88 ** generated by the ALTER TABLE ... RENAME command to modify the definition
89 ** of any foreign key constraints that use the table being renamed as the
90 ** parent table. It is passed three arguments:
91 **
92 ** 1) The complete text of the CREATE TABLE statement being modified,
93 ** 2) The old name of the table being renamed, and
94 ** 3) The new name of the table being renamed.
95 **
96 ** It returns the new CREATE TABLE statement. For example:
97 **
98 ** sqlite_rename_parent('CREATE TABLE t1(a REFERENCES t2)', 't2', 't3')
99 ** -> 'CREATE TABLE t1(a REFERENCES t3)'
100 */
101 #ifndef SQLITE_OMIT_FOREIGN_KEY
102 static void renameParentFunc(
103 sqlite3_context *context,
104 int NotUsed,
105 sqlite3_value **argv
106 ){
107 sqlite3 *db = sqlite3_context_db_handle(context);
108 char *zOutput = 0;
109 char *zResult;
110 unsigned char const *zInput = sqlite3_value_text(argv[0]);
111 unsigned char const *zOld = sqlite3_value_text(argv[1]);
112 unsigned char const *zNew = sqlite3_value_text(argv[2]);
113
114 unsigned const char *z; /* Pointer to token */
115 int n; /* Length of token z */
116 int token; /* Type of token */
117
118 UNUSED_PARAMETER(NotUsed);
119 if( zInput==0 || zOld==0 ) return;
120 for(z=zInput; *z; z=z+n){
121 n = sqlite3GetToken(z, &token);
122 if( token==TK_REFERENCES ){
123 char *zParent;
124 do {
125 z += n;
126 n = sqlite3GetToken(z, &token);
127 }while( token==TK_SPACE );
128
129 if( token==TK_ILLEGAL ) break;
130 zParent = sqlite3DbStrNDup(db, (const char *)z, n);
131 if( zParent==0 ) break;
132 sqlite3Dequote(zParent);
133 if( 0==sqlite3StrICmp((const char *)zOld, zParent) ){
134 char *zOut = sqlite3MPrintf(db, "%s%.*s\"%w\"",
135 (zOutput?zOutput:""), (int)(z-zInput), zInput, (const char *)zNew
136 );
137 sqlite3DbFree(db, zOutput);
138 zOutput = zOut;
139 zInput = &z[n];
140 }
141 sqlite3DbFree(db, zParent);
142 }
143 }
144
145 zResult = sqlite3MPrintf(db, "%s%s", (zOutput?zOutput:""), zInput),
146 sqlite3_result_text(context, zResult, -1, SQLITE_DYNAMIC);
147 sqlite3DbFree(db, zOutput);
148 }
149 #endif
150
151 #ifndef SQLITE_OMIT_TRIGGER
152 /* This function is used by SQL generated to implement the
153 ** ALTER TABLE command. The first argument is the text of a CREATE TRIGGER
154 ** statement. The second is a table name. The table name in the CREATE
155 ** TRIGGER statement is replaced with the third argument and the result
156 ** returned. This is analagous to renameTableFunc() above, except for CREATE
157 ** TRIGGER, not CREATE INDEX and CREATE TABLE.
158 */
159 static void renameTriggerFunc(
160 sqlite3_context *context,
161 int NotUsed,
162 sqlite3_value **argv
163 ){
164 unsigned char const *zSql = sqlite3_value_text(argv[0]);
165 unsigned char const *zTableName = sqlite3_value_text(argv[1]);
166
167 int token;
168 Token tname;
169 int dist = 3;
170 unsigned char const *zCsr = zSql;
171 int len = 0;
172 char *zRet;
173 sqlite3 *db = sqlite3_context_db_handle(context);
174
175 UNUSED_PARAMETER(NotUsed);
176
177 /* The principle used to locate the table name in the CREATE TRIGGER
178 ** statement is that the table name is the first token that is immediately
179 ** preceded by either TK_ON or TK_DOT and immediately followed by one
180 ** of TK_WHEN, TK_BEGIN or TK_FOR.
181 */
182 if( zSql ){
183 do {
184
185 if( !*zCsr ){
186 /* Ran out of input before finding the table name. Return NULL. */
187 return;
188 }
189
190 /* Store the token that zCsr points to in tname. */
191 tname.z = (char*)zCsr;
192 tname.n = len;
193
194 /* Advance zCsr to the next token. Store that token type in 'token',
195 ** and its length in 'len' (to be used next iteration of this loop).
196 */
197 do {
198 zCsr += len;
199 len = sqlite3GetToken(zCsr, &token);
200 }while( token==TK_SPACE );
201 assert( len>0 );
202
203 /* Variable 'dist' stores the number of tokens read since the most
204 ** recent TK_DOT or TK_ON. This means that when a WHEN, FOR or BEGIN
205 ** token is read and 'dist' equals 2, the condition stated above
206 ** to be met.
207 **
208 ** Note that ON cannot be a database, table or column name, so
209 ** there is no need to worry about syntax like
210 ** "CREATE TRIGGER ... ON ON.ON BEGIN ..." etc.
211 */
212 dist++;
213 if( token==TK_DOT || token==TK_ON ){
214 dist = 0;
215 }
216 } while( dist!=2 || (token!=TK_WHEN && token!=TK_FOR && token!=TK_BEGIN) );
217
218 /* Variable tname now contains the token that is the old table-name
219 ** in the CREATE TRIGGER statement.
220 */
221 zRet = sqlite3MPrintf(db, "%.*s\"%w\"%s", (int)(((u8*)tname.z) - zSql),
222 zSql, zTableName, tname.z+tname.n);
223 sqlite3_result_text(context, zRet, -1, SQLITE_DYNAMIC);
224 }
225 }
226 #endif /* !SQLITE_OMIT_TRIGGER */
227
228 /*
229 ** Register built-in functions used to help implement ALTER TABLE
230 */
231 void sqlite3AlterFunctions(void){
232 static SQLITE_WSD FuncDef aAlterTableFuncs[] = {
233 FUNCTION(sqlite_rename_table, 2, 0, 0, renameTableFunc),
234 #ifndef SQLITE_OMIT_TRIGGER
235 FUNCTION(sqlite_rename_trigger, 2, 0, 0, renameTriggerFunc),
236 #endif
237 #ifndef SQLITE_OMIT_FOREIGN_KEY
238 FUNCTION(sqlite_rename_parent, 3, 0, 0, renameParentFunc),
239 #endif
240 };
241 int i;
242 FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
243 FuncDef *aFunc = (FuncDef*)&GLOBAL(FuncDef, aAlterTableFuncs);
244
245 for(i=0; i<ArraySize(aAlterTableFuncs); i++){
246 sqlite3FuncDefInsert(pHash, &aFunc[i]);
247 }
248 }
249
250 /*
251 ** This function is used to create the text of expressions of the form:
252 **
253 ** name=<constant1> OR name=<constant2> OR ...
254 **
255 ** If argument zWhere is NULL, then a pointer string containing the text
256 ** "name=<constant>" is returned, where <constant> is the quoted version
257 ** of the string passed as argument zConstant. The returned buffer is
258 ** allocated using sqlite3DbMalloc(). It is the responsibility of the
259 ** caller to ensure that it is eventually freed.
260 **
261 ** If argument zWhere is not NULL, then the string returned is
262 ** "<where> OR name=<constant>", where <where> is the contents of zWhere.
263 ** In this case zWhere is passed to sqlite3DbFree() before returning.
264 **
265 */
266 static char *whereOrName(sqlite3 *db, char *zWhere, char *zConstant){
267 char *zNew;
268 if( !zWhere ){
269 zNew = sqlite3MPrintf(db, "name=%Q", zConstant);
270 }else{
271 zNew = sqlite3MPrintf(db, "%s OR name=%Q", zWhere, zConstant);
272 sqlite3DbFree(db, zWhere);
273 }
274 return zNew;
275 }
276
277 #if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
278 /*
279 ** Generate the text of a WHERE expression which can be used to select all
280 ** tables that have foreign key constraints that refer to table pTab (i.e.
281 ** constraints for which pTab is the parent table) from the sqlite_master
282 ** table.
283 */
284 static char *whereForeignKeys(Parse *pParse, Table *pTab){
285 FKey *p;
286 char *zWhere = 0;
287 for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
288 zWhere = whereOrName(pParse->db, zWhere, p->pFrom->zName);
289 }
290 return zWhere;
291 }
292 #endif
293
294 /*
295 ** Generate the text of a WHERE expression which can be used to select all
296 ** temporary triggers on table pTab from the sqlite_temp_master table. If
297 ** table pTab has no temporary triggers, or is itself stored in the
298 ** temporary database, NULL is returned.
299 */
300 static char *whereTempTriggers(Parse *pParse, Table *pTab){
301 Trigger *pTrig;
302 char *zWhere = 0;
303 const Schema *pTempSchema = pParse->db->aDb[1].pSchema; /* Temp db schema */
304
305 /* If the table is not located in the temp-db (in which case NULL is
306 ** returned, loop through the tables list of triggers. For each trigger
307 ** that is not part of the temp-db schema, add a clause to the WHERE
308 ** expression being built up in zWhere.
309 */
310 if( pTab->pSchema!=pTempSchema ){
311 sqlite3 *db = pParse->db;
312 for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
313 if( pTrig->pSchema==pTempSchema ){
314 zWhere = whereOrName(db, zWhere, pTrig->zName);
315 }
316 }
317 }
318 if( zWhere ){
319 char *zNew = sqlite3MPrintf(pParse->db, "type='trigger' AND (%s)", zWhere);
320 sqlite3DbFree(pParse->db, zWhere);
321 zWhere = zNew;
322 }
323 return zWhere;
324 }
325
326 /*
327 ** Generate code to drop and reload the internal representation of table
328 ** pTab from the database, including triggers and temporary triggers.
329 ** Argument zName is the name of the table in the database schema at
330 ** the time the generated code is executed. This can be different from
331 ** pTab->zName if this function is being called to code part of an
332 ** "ALTER TABLE RENAME TO" statement.
333 */
334 static void reloadTableSchema(Parse *pParse, Table *pTab, const char *zName){
335 Vdbe *v;
336 char *zWhere;
337 int iDb; /* Index of database containing pTab */
338 #ifndef SQLITE_OMIT_TRIGGER
339 Trigger *pTrig;
340 #endif
341
342 v = sqlite3GetVdbe(pParse);
343 if( NEVER(v==0) ) return;
344 assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
345 iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
346 assert( iDb>=0 );
347
348 #ifndef SQLITE_OMIT_TRIGGER
349 /* Drop any table triggers from the internal schema. */
350 for(pTrig=sqlite3TriggerList(pParse, pTab); pTrig; pTrig=pTrig->pNext){
351 int iTrigDb = sqlite3SchemaToIndex(pParse->db, pTrig->pSchema);
352 assert( iTrigDb==iDb || iTrigDb==1 );
353 sqlite3VdbeAddOp4(v, OP_DropTrigger, iTrigDb, 0, 0, pTrig->zName, 0);
354 }
355 #endif
356
357 /* Drop the table and index from the internal schema. */
358 sqlite3VdbeAddOp4(v, OP_DropTable, iDb, 0, 0, pTab->zName, 0);
359
360 /* Reload the table, index and permanent trigger schemas. */
361 zWhere = sqlite3MPrintf(pParse->db, "tbl_name=%Q", zName);
362 if( !zWhere ) return;
363 sqlite3VdbeAddParseSchemaOp(v, iDb, zWhere);
364
365 #ifndef SQLITE_OMIT_TRIGGER
366 /* Now, if the table is not stored in the temp database, reload any temp
367 ** triggers. Don't use IN(...) in case SQLITE_OMIT_SUBQUERY is defined.
368 */
369 if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
370 sqlite3VdbeAddParseSchemaOp(v, 1, zWhere);
371 }
372 #endif
373 }
374
375 /*
376 ** Parameter zName is the name of a table that is about to be altered
377 ** (either with ALTER TABLE ... RENAME TO or ALTER TABLE ... ADD COLUMN).
378 ** If the table is a system table, this function leaves an error message
379 ** in pParse->zErr (system tables may not be altered) and returns non-zero.
380 **
381 ** Or, if zName is not a system table, zero is returned.
382 */
383 static int isSystemTable(Parse *pParse, const char *zName){
384 if( sqlite3Strlen30(zName)>6 && 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){
385 sqlite3ErrorMsg(pParse, "table %s may not be altered", zName);
386 return 1;
387 }
388 return 0;
389 }
390
391 /*
392 ** Generate code to implement the "ALTER TABLE xxx RENAME TO yyy"
393 ** command.
394 */
395 void sqlite3AlterRenameTable(
396 Parse *pParse, /* Parser context. */
397 SrcList *pSrc, /* The table to rename. */
398 Token *pName /* The new table name. */
399 ){
400 int iDb; /* Database that contains the table */
401 char *zDb; /* Name of database iDb */
402 Table *pTab; /* Table being renamed */
403 char *zName = 0; /* NULL-terminated version of pName */
404 sqlite3 *db = pParse->db; /* Database connection */
405 int nTabName; /* Number of UTF-8 characters in zTabName */
406 const char *zTabName; /* Original name of the table */
407 Vdbe *v;
408 #ifndef SQLITE_OMIT_TRIGGER
409 char *zWhere = 0; /* Where clause to locate temp triggers */
410 #endif
411 VTable *pVTab = 0; /* Non-zero if this is a v-tab with an xRename() */
412 int savedDbFlags; /* Saved value of db->flags */
413
414 savedDbFlags = db->flags;
415 if( NEVER(db->mallocFailed) ) goto exit_rename_table;
416 assert( pSrc->nSrc==1 );
417 assert( sqlite3BtreeHoldsAllMutexes(pParse->db) );
418
419 pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
420 if( !pTab ) goto exit_rename_table;
421 iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
422 zDb = db->aDb[iDb].zName;
423 db->flags |= SQLITE_PreferBuiltin;
424
425 /* Get a NULL terminated version of the new table name. */
426 zName = sqlite3NameFromToken(db, pName);
427 if( !zName ) goto exit_rename_table;
428
429 /* Check that a table or index named 'zName' does not already exist
430 ** in database iDb. If so, this is an error.
431 */
432 if( sqlite3FindTable(db, zName, zDb) || sqlite3FindIndex(db, zName, zDb) ){
433 sqlite3ErrorMsg(pParse,
434 "there is already another table or index with this name: %s", zName);
435 goto exit_rename_table;
436 }
437
438 /* Make sure it is not a system table being altered, or a reserved name
439 ** that the table is being renamed to.
440 */
441 if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
442 goto exit_rename_table;
443 }
444 if( SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){ goto
445 exit_rename_table;
446 }
447
448 #ifndef SQLITE_OMIT_VIEW
449 if( pTab->pSelect ){
450 sqlite3ErrorMsg(pParse, "view %s may not be altered", pTab->zName);
451 goto exit_rename_table;
452 }
453 #endif
454
455 #ifndef SQLITE_OMIT_AUTHORIZATION
456 /* Invoke the authorization callback. */
457 if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
458 goto exit_rename_table;
459 }
460 #endif
461
462 #ifndef SQLITE_OMIT_VIRTUALTABLE
463 if( sqlite3ViewGetColumnNames(pParse, pTab) ){
464 goto exit_rename_table;
465 }
466 if( IsVirtual(pTab) ){
467 pVTab = sqlite3GetVTable(db, pTab);
468 if( pVTab->pVtab->pModule->xRename==0 ){
469 pVTab = 0;
470 }
471 }
472 #endif
473
474 /* Begin a transaction for database iDb.
475 ** Then modify the schema cookie (since the ALTER TABLE modifies the
476 ** schema). Open a statement transaction if the table is a virtual
477 ** table.
478 */
479 v = sqlite3GetVdbe(pParse);
480 if( v==0 ){
481 goto exit_rename_table;
482 }
483 sqlite3BeginWriteOperation(pParse, pVTab!=0, iDb);
484 sqlite3ChangeCookie(pParse, iDb);
485
486 /* If this is a virtual table, invoke the xRename() function if
487 ** one is defined. The xRename() callback will modify the names
488 ** of any resources used by the v-table implementation (including other
489 ** SQLite tables) that are identified by the name of the virtual table.
490 */
491 #ifndef SQLITE_OMIT_VIRTUALTABLE
492 if( pVTab ){
493 int i = ++pParse->nMem;
494 sqlite3VdbeLoadString(v, i, zName);
495 sqlite3VdbeAddOp4(v, OP_VRename, i, 0, 0,(const char*)pVTab, P4_VTAB);
496 sqlite3MayAbort(pParse);
497 }
498 #endif
499
500 /* figure out how many UTF-8 characters are in zName */
501 zTabName = pTab->zName;
502 nTabName = sqlite3Utf8CharLen(zTabName, -1);
503
504 #if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
505 if( db->flags&SQLITE_ForeignKeys ){
506 /* If foreign-key support is enabled, rewrite the CREATE TABLE
507 ** statements corresponding to all child tables of foreign key constraints
508 ** for which the renamed table is the parent table. */
509 if( (zWhere=whereForeignKeys(pParse, pTab))!=0 ){
510 sqlite3NestedParse(pParse,
511 "UPDATE \"%w\".%s SET "
512 "sql = sqlite_rename_parent(sql, %Q, %Q) "
513 "WHERE %s;", zDb, SCHEMA_TABLE(iDb), zTabName, zName, zWhere);
514 sqlite3DbFree(db, zWhere);
515 }
516 }
517 #endif
518
519 /* Modify the sqlite_master table to use the new table name. */
520 sqlite3NestedParse(pParse,
521 "UPDATE %Q.%s SET "
522 #ifdef SQLITE_OMIT_TRIGGER
523 "sql = sqlite_rename_table(sql, %Q), "
524 #else
525 "sql = CASE "
526 "WHEN type = 'trigger' THEN sqlite_rename_trigger(sql, %Q)"
527 "ELSE sqlite_rename_table(sql, %Q) END, "
528 #endif
529 "tbl_name = %Q, "
530 "name = CASE "
531 "WHEN type='table' THEN %Q "
532 "WHEN name LIKE 'sqlite_autoindex%%' AND type='index' THEN "
533 "'sqlite_autoindex_' || %Q || substr(name,%d+18) "
534 "ELSE name END "
535 "WHERE tbl_name=%Q COLLATE nocase AND "
536 "(type='table' OR type='index' OR type='trigger');",
537 zDb, SCHEMA_TABLE(iDb), zName, zName, zName,
538 #ifndef SQLITE_OMIT_TRIGGER
539 zName,
540 #endif
541 zName, nTabName, zTabName
542 );
543
544 #ifndef SQLITE_OMIT_AUTOINCREMENT
545 /* If the sqlite_sequence table exists in this database, then update
546 ** it with the new table name.
547 */
548 if( sqlite3FindTable(db, "sqlite_sequence", zDb) ){
549 sqlite3NestedParse(pParse,
550 "UPDATE \"%w\".sqlite_sequence set name = %Q WHERE name = %Q",
551 zDb, zName, pTab->zName);
552 }
553 #endif
554
555 #ifndef SQLITE_OMIT_TRIGGER
556 /* If there are TEMP triggers on this table, modify the sqlite_temp_master
557 ** table. Don't do this if the table being ALTERed is itself located in
558 ** the temp database.
559 */
560 if( (zWhere=whereTempTriggers(pParse, pTab))!=0 ){
561 sqlite3NestedParse(pParse,
562 "UPDATE sqlite_temp_master SET "
563 "sql = sqlite_rename_trigger(sql, %Q), "
564 "tbl_name = %Q "
565 "WHERE %s;", zName, zName, zWhere);
566 sqlite3DbFree(db, zWhere);
567 }
568 #endif
569
570 #if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
571 if( db->flags&SQLITE_ForeignKeys ){
572 FKey *p;
573 for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
574 Table *pFrom = p->pFrom;
575 if( pFrom!=pTab ){
576 reloadTableSchema(pParse, p->pFrom, pFrom->zName);
577 }
578 }
579 }
580 #endif
581
582 /* Drop and reload the internal table schema. */
583 reloadTableSchema(pParse, pTab, zName);
584
585 exit_rename_table:
586 sqlite3SrcListDelete(db, pSrc);
587 sqlite3DbFree(db, zName);
588 db->flags = savedDbFlags;
589 }
590
591
592 /*
593 ** Generate code to make sure the file format number is at least minFormat.
594 ** The generated code will increase the file format number if necessary.
595 */
596 void sqlite3MinimumFileFormat(Parse *pParse, int iDb, int minFormat){
597 Vdbe *v;
598 v = sqlite3GetVdbe(pParse);
599 /* The VDBE should have been allocated before this routine is called.
600 ** If that allocation failed, we would have quit before reaching this
601 ** point */
602 if( ALWAYS(v) ){
603 int r1 = sqlite3GetTempReg(pParse);
604 int r2 = sqlite3GetTempReg(pParse);
605 int addr1;
606 sqlite3VdbeAddOp3(v, OP_ReadCookie, iDb, r1, BTREE_FILE_FORMAT);
607 sqlite3VdbeUsesBtree(v, iDb);
608 sqlite3VdbeAddOp2(v, OP_Integer, minFormat, r2);
609 addr1 = sqlite3VdbeAddOp3(v, OP_Ge, r2, 0, r1);
610 sqlite3VdbeChangeP5(v, SQLITE_NOTNULL); VdbeCoverage(v);
611 sqlite3VdbeAddOp3(v, OP_SetCookie, iDb, BTREE_FILE_FORMAT, r2);
612 sqlite3VdbeJumpHere(v, addr1);
613 sqlite3ReleaseTempReg(pParse, r1);
614 sqlite3ReleaseTempReg(pParse, r2);
615 }
616 }
617
618 /*
619 ** This function is called after an "ALTER TABLE ... ADD" statement
620 ** has been parsed. Argument pColDef contains the text of the new
621 ** column definition.
622 **
623 ** The Table structure pParse->pNewTable was extended to include
624 ** the new column during parsing.
625 */
626 void sqlite3AlterFinishAddColumn(Parse *pParse, Token *pColDef){
627 Table *pNew; /* Copy of pParse->pNewTable */
628 Table *pTab; /* Table being altered */
629 int iDb; /* Database number */
630 const char *zDb; /* Database name */
631 const char *zTab; /* Table name */
632 char *zCol; /* Null-terminated column definition */
633 Column *pCol; /* The new column */
634 Expr *pDflt; /* Default value for the new column */
635 sqlite3 *db; /* The database connection; */
636
637 db = pParse->db;
638 if( pParse->nErr || db->mallocFailed ) return;
639 pNew = pParse->pNewTable;
640 assert( pNew );
641
642 assert( sqlite3BtreeHoldsAllMutexes(db) );
643 iDb = sqlite3SchemaToIndex(db, pNew->pSchema);
644 zDb = db->aDb[iDb].zName;
645 zTab = &pNew->zName[16]; /* Skip the "sqlite_altertab_" prefix on the name */
646 pCol = &pNew->aCol[pNew->nCol-1];
647 pDflt = pCol->pDflt;
648 pTab = sqlite3FindTable(db, zTab, zDb);
649 assert( pTab );
650
651 #ifndef SQLITE_OMIT_AUTHORIZATION
652 /* Invoke the authorization callback. */
653 if( sqlite3AuthCheck(pParse, SQLITE_ALTER_TABLE, zDb, pTab->zName, 0) ){
654 return;
655 }
656 #endif
657
658 /* If the default value for the new column was specified with a
659 ** literal NULL, then set pDflt to 0. This simplifies checking
660 ** for an SQL NULL default below.
661 */
662 if( pDflt && pDflt->op==TK_NULL ){
663 pDflt = 0;
664 }
665
666 /* Check that the new column is not specified as PRIMARY KEY or UNIQUE.
667 ** If there is a NOT NULL constraint, then the default value for the
668 ** column must not be NULL.
669 */
670 if( pCol->colFlags & COLFLAG_PRIMKEY ){
671 sqlite3ErrorMsg(pParse, "Cannot add a PRIMARY KEY column");
672 return;
673 }
674 if( pNew->pIndex ){
675 sqlite3ErrorMsg(pParse, "Cannot add a UNIQUE column");
676 return;
677 }
678 if( (db->flags&SQLITE_ForeignKeys) && pNew->pFKey && pDflt ){
679 sqlite3ErrorMsg(pParse,
680 "Cannot add a REFERENCES column with non-NULL default value");
681 return;
682 }
683 if( pCol->notNull && !pDflt ){
684 sqlite3ErrorMsg(pParse,
685 "Cannot add a NOT NULL column with default value NULL");
686 return;
687 }
688
689 /* Ensure the default expression is something that sqlite3ValueFromExpr()
690 ** can handle (i.e. not CURRENT_TIME etc.)
691 */
692 if( pDflt ){
693 sqlite3_value *pVal = 0;
694 int rc;
695 rc = sqlite3ValueFromExpr(db, pDflt, SQLITE_UTF8, SQLITE_AFF_BLOB, &pVal);
696 assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
697 if( rc!=SQLITE_OK ){
698 db->mallocFailed = 1;
699 return;
700 }
701 if( !pVal ){
702 sqlite3ErrorMsg(pParse, "Cannot add a column with non-constant default");
703 return;
704 }
705 sqlite3ValueFree(pVal);
706 }
707
708 /* Modify the CREATE TABLE statement. */
709 zCol = sqlite3DbStrNDup(db, (char*)pColDef->z, pColDef->n);
710 if( zCol ){
711 char *zEnd = &zCol[pColDef->n-1];
712 int savedDbFlags = db->flags;
713 while( zEnd>zCol && (*zEnd==';' || sqlite3Isspace(*zEnd)) ){
714 *zEnd-- = '\0';
715 }
716 db->flags |= SQLITE_PreferBuiltin;
717 sqlite3NestedParse(pParse,
718 "UPDATE \"%w\".%s SET "
719 "sql = substr(sql,1,%d) || ', ' || %Q || substr(sql,%d) "
720 "WHERE type = 'table' AND name = %Q",
721 zDb, SCHEMA_TABLE(iDb), pNew->addColOffset, zCol, pNew->addColOffset+1,
722 zTab
723 );
724 sqlite3DbFree(db, zCol);
725 db->flags = savedDbFlags;
726 }
727
728 /* If the default value of the new column is NULL, then set the file
729 ** format to 2. If the default value of the new column is not NULL,
730 ** the file format becomes 3.
731 */
732 sqlite3MinimumFileFormat(pParse, iDb, pDflt ? 3 : 2);
733
734 /* Reload the schema of the modified table. */
735 reloadTableSchema(pParse, pTab, pTab->zName);
736 }
737
738 /*
739 ** This function is called by the parser after the table-name in
740 ** an "ALTER TABLE <table-name> ADD" statement is parsed. Argument
741 ** pSrc is the full-name of the table being altered.
742 **
743 ** This routine makes a (partial) copy of the Table structure
744 ** for the table being altered and sets Parse.pNewTable to point
745 ** to it. Routines called by the parser as the column definition
746 ** is parsed (i.e. sqlite3AddColumn()) add the new Column data to
747 ** the copy. The copy of the Table structure is deleted by tokenize.c
748 ** after parsing is finished.
749 **
750 ** Routine sqlite3AlterFinishAddColumn() will be called to complete
751 ** coding the "ALTER TABLE ... ADD" statement.
752 */
753 void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
754 Table *pNew;
755 Table *pTab;
756 Vdbe *v;
757 int iDb;
758 int i;
759 int nAlloc;
760 sqlite3 *db = pParse->db;
761
762 /* Look up the table being altered. */
763 assert( pParse->pNewTable==0 );
764 assert( sqlite3BtreeHoldsAllMutexes(db) );
765 if( db->mallocFailed ) goto exit_begin_add_column;
766 pTab = sqlite3LocateTableItem(pParse, 0, &pSrc->a[0]);
767 if( !pTab ) goto exit_begin_add_column;
768
769 #ifndef SQLITE_OMIT_VIRTUALTABLE
770 if( IsVirtual(pTab) ){
771 sqlite3ErrorMsg(pParse, "virtual tables may not be altered");
772 goto exit_begin_add_column;
773 }
774 #endif
775
776 /* Make sure this is not an attempt to ALTER a view. */
777 if( pTab->pSelect ){
778 sqlite3ErrorMsg(pParse, "Cannot add a column to a view");
779 goto exit_begin_add_column;
780 }
781 if( SQLITE_OK!=isSystemTable(pParse, pTab->zName) ){
782 goto exit_begin_add_column;
783 }
784
785 assert( pTab->addColOffset>0 );
786 iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
787
788 /* Put a copy of the Table struct in Parse.pNewTable for the
789 ** sqlite3AddColumn() function and friends to modify. But modify
790 ** the name by adding an "sqlite_altertab_" prefix. By adding this
791 ** prefix, we insure that the name will not collide with an existing
792 ** table because user table are not allowed to have the "sqlite_"
793 ** prefix on their name.
794 */
795 pNew = (Table*)sqlite3DbMallocZero(db, sizeof(Table));
796 if( !pNew ) goto exit_begin_add_column;
797 pParse->pNewTable = pNew;
798 pNew->nRef = 1;
799 pNew->nCol = pTab->nCol;
800 assert( pNew->nCol>0 );
801 nAlloc = (((pNew->nCol-1)/8)*8)+8;
802 assert( nAlloc>=pNew->nCol && nAlloc%8==0 && nAlloc-pNew->nCol<8 );
803 pNew->aCol = (Column*)sqlite3DbMallocZero(db, sizeof(Column)*nAlloc);
804 pNew->zName = sqlite3MPrintf(db, "sqlite_altertab_%s", pTab->zName);
805 if( !pNew->aCol || !pNew->zName ){
806 db->mallocFailed = 1;
807 goto exit_begin_add_column;
808 }
809 memcpy(pNew->aCol, pTab->aCol, sizeof(Column)*pNew->nCol);
810 for(i=0; i<pNew->nCol; i++){
811 Column *pCol = &pNew->aCol[i];
812 pCol->zName = sqlite3DbStrDup(db, pCol->zName);
813 pCol->zColl = 0;
814 pCol->zType = 0;
815 pCol->pDflt = 0;
816 pCol->zDflt = 0;
817 }
818 pNew->pSchema = db->aDb[iDb].pSchema;
819 pNew->addColOffset = pTab->addColOffset;
820 pNew->nRef = 1;
821
822 /* Begin a transaction and increment the schema cookie. */
823 sqlite3BeginWriteOperation(pParse, 0, iDb);
824 v = sqlite3GetVdbe(pParse);
825 if( !v ) goto exit_begin_add_column;
826 sqlite3ChangeCookie(pParse, iDb);
827
828 exit_begin_add_column:
829 sqlite3SrcListDelete(db, pSrc);
830 return;
831 }
832 #endif /* SQLITE_ALTER_TABLE */
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