| 1 | /*------------------------------------------------------------------------- |
| 2 | * |
| 3 | * pg_constraint.c |
| 4 | * routines to support manipulation of the pg_constraint relation |
| 5 | * |
| 6 | * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group |
| 7 | * Portions Copyright (c) 1994, Regents of the University of California |
| 8 | * |
| 9 | * |
| 10 | * IDENTIFICATION |
| 11 | * src/backend/catalog/pg_constraint.c |
| 12 | * |
| 13 | *------------------------------------------------------------------------- |
| 14 | */ |
| 15 | #include "postgres.h" |
| 16 | |
| 17 | #include "access/genam.h" |
| 18 | #include "access/htup_details.h" |
| 19 | #include "access/sysattr.h" |
| 20 | #include "access/table.h" |
| 21 | #include "access/tupconvert.h" |
| 22 | #include "access/xact.h" |
| 23 | #include "catalog/catalog.h" |
| 24 | #include "catalog/dependency.h" |
| 25 | #include "catalog/indexing.h" |
| 26 | #include "catalog/objectaccess.h" |
| 27 | #include "catalog/pg_constraint.h" |
| 28 | #include "catalog/pg_operator.h" |
| 29 | #include "catalog/pg_type.h" |
| 30 | #include "commands/defrem.h" |
| 31 | #include "commands/tablecmds.h" |
| 32 | #include "utils/array.h" |
| 33 | #include "utils/builtins.h" |
| 34 | #include "utils/fmgroids.h" |
| 35 | #include "utils/lsyscache.h" |
| 36 | #include "utils/rel.h" |
| 37 | #include "utils/syscache.h" |
| 38 | |
| 39 | |
| 40 | /* |
| 41 | * CreateConstraintEntry |
| 42 | * Create a constraint table entry. |
| 43 | * |
| 44 | * Subsidiary records (such as triggers or indexes to implement the |
| 45 | * constraint) are *not* created here. But we do make dependency links |
| 46 | * from the constraint to the things it depends on. |
| 47 | * |
| 48 | * The new constraint's OID is returned. |
| 49 | */ |
| 50 | Oid |
| 51 | CreateConstraintEntry(const char *constraintName, |
| 52 | Oid constraintNamespace, |
| 53 | char constraintType, |
| 54 | bool isDeferrable, |
| 55 | bool isDeferred, |
| 56 | bool isValidated, |
| 57 | Oid parentConstrId, |
| 58 | Oid relId, |
| 59 | const int16 *constraintKey, |
| 60 | int constraintNKeys, |
| 61 | int constraintNTotalKeys, |
| 62 | Oid domainId, |
| 63 | Oid indexRelId, |
| 64 | Oid foreignRelId, |
| 65 | const int16 *foreignKey, |
| 66 | const Oid *pfEqOp, |
| 67 | const Oid *ppEqOp, |
| 68 | const Oid *ffEqOp, |
| 69 | int foreignNKeys, |
| 70 | char foreignUpdateType, |
| 71 | char foreignDeleteType, |
| 72 | char foreignMatchType, |
| 73 | const Oid *exclOp, |
| 74 | Node *conExpr, |
| 75 | const char *conBin, |
| 76 | bool conIsLocal, |
| 77 | int conInhCount, |
| 78 | bool conNoInherit, |
| 79 | bool is_internal) |
| 80 | { |
| 81 | Relation conDesc; |
| 82 | Oid conOid; |
| 83 | HeapTuple tup; |
| 84 | bool nulls[Natts_pg_constraint]; |
| 85 | Datum values[Natts_pg_constraint]; |
| 86 | ArrayType *conkeyArray; |
| 87 | ArrayType *confkeyArray; |
| 88 | ArrayType *conpfeqopArray; |
| 89 | ArrayType *conppeqopArray; |
| 90 | ArrayType *conffeqopArray; |
| 91 | ArrayType *conexclopArray; |
| 92 | NameData cname; |
| 93 | int i; |
| 94 | ObjectAddress conobject; |
| 95 | |
| 96 | conDesc = table_open(ConstraintRelationId, RowExclusiveLock); |
| 97 | |
| 98 | Assert(constraintName); |
| 99 | namestrcpy(&cname, constraintName); |
| 100 | |
| 101 | /* |
| 102 | * Convert C arrays into Postgres arrays. |
| 103 | */ |
| 104 | if (constraintNKeys > 0) |
| 105 | { |
| 106 | Datum *conkey; |
| 107 | |
| 108 | conkey = (Datum *) palloc(constraintNKeys * sizeof(Datum)); |
| 109 | for (i = 0; i < constraintNKeys; i++) |
| 110 | conkey[i] = Int16GetDatum(constraintKey[i]); |
| 111 | conkeyArray = construct_array(conkey, constraintNKeys, |
| 112 | INT2OID, 2, true, 's'); |
| 113 | } |
| 114 | else |
| 115 | conkeyArray = NULL; |
| 116 | |
| 117 | if (foreignNKeys > 0) |
| 118 | { |
| 119 | Datum *fkdatums; |
| 120 | |
| 121 | fkdatums = (Datum *) palloc(foreignNKeys * sizeof(Datum)); |
| 122 | for (i = 0; i < foreignNKeys; i++) |
| 123 | fkdatums[i] = Int16GetDatum(foreignKey[i]); |
| 124 | confkeyArray = construct_array(fkdatums, foreignNKeys, |
| 125 | INT2OID, 2, true, 's'); |
| 126 | for (i = 0; i < foreignNKeys; i++) |
| 127 | fkdatums[i] = ObjectIdGetDatum(pfEqOp[i]); |
| 128 | conpfeqopArray = construct_array(fkdatums, foreignNKeys, |
| 129 | OIDOID, sizeof(Oid), true, 'i'); |
| 130 | for (i = 0; i < foreignNKeys; i++) |
| 131 | fkdatums[i] = ObjectIdGetDatum(ppEqOp[i]); |
| 132 | conppeqopArray = construct_array(fkdatums, foreignNKeys, |
| 133 | OIDOID, sizeof(Oid), true, 'i'); |
| 134 | for (i = 0; i < foreignNKeys; i++) |
| 135 | fkdatums[i] = ObjectIdGetDatum(ffEqOp[i]); |
| 136 | conffeqopArray = construct_array(fkdatums, foreignNKeys, |
| 137 | OIDOID, sizeof(Oid), true, 'i'); |
| 138 | } |
| 139 | else |
| 140 | { |
| 141 | confkeyArray = NULL; |
| 142 | conpfeqopArray = NULL; |
| 143 | conppeqopArray = NULL; |
| 144 | conffeqopArray = NULL; |
| 145 | } |
| 146 | |
| 147 | if (exclOp != NULL) |
| 148 | { |
| 149 | Datum *opdatums; |
| 150 | |
| 151 | opdatums = (Datum *) palloc(constraintNKeys * sizeof(Datum)); |
| 152 | for (i = 0; i < constraintNKeys; i++) |
| 153 | opdatums[i] = ObjectIdGetDatum(exclOp[i]); |
| 154 | conexclopArray = construct_array(opdatums, constraintNKeys, |
| 155 | OIDOID, sizeof(Oid), true, 'i'); |
| 156 | } |
| 157 | else |
| 158 | conexclopArray = NULL; |
| 159 | |
| 160 | /* initialize nulls and values */ |
| 161 | for (i = 0; i < Natts_pg_constraint; i++) |
| 162 | { |
| 163 | nulls[i] = false; |
| 164 | values[i] = (Datum) NULL; |
| 165 | } |
| 166 | |
| 167 | conOid = GetNewOidWithIndex(conDesc, ConstraintOidIndexId, |
| 168 | Anum_pg_constraint_oid); |
| 169 | values[Anum_pg_constraint_oid - 1] = ObjectIdGetDatum(conOid); |
| 170 | values[Anum_pg_constraint_conname - 1] = NameGetDatum(&cname); |
| 171 | values[Anum_pg_constraint_connamespace - 1] = ObjectIdGetDatum(constraintNamespace); |
| 172 | values[Anum_pg_constraint_contype - 1] = CharGetDatum(constraintType); |
| 173 | values[Anum_pg_constraint_condeferrable - 1] = BoolGetDatum(isDeferrable); |
| 174 | values[Anum_pg_constraint_condeferred - 1] = BoolGetDatum(isDeferred); |
| 175 | values[Anum_pg_constraint_convalidated - 1] = BoolGetDatum(isValidated); |
| 176 | values[Anum_pg_constraint_conrelid - 1] = ObjectIdGetDatum(relId); |
| 177 | values[Anum_pg_constraint_contypid - 1] = ObjectIdGetDatum(domainId); |
| 178 | values[Anum_pg_constraint_conindid - 1] = ObjectIdGetDatum(indexRelId); |
| 179 | values[Anum_pg_constraint_conparentid - 1] = ObjectIdGetDatum(parentConstrId); |
| 180 | values[Anum_pg_constraint_confrelid - 1] = ObjectIdGetDatum(foreignRelId); |
| 181 | values[Anum_pg_constraint_confupdtype - 1] = CharGetDatum(foreignUpdateType); |
| 182 | values[Anum_pg_constraint_confdeltype - 1] = CharGetDatum(foreignDeleteType); |
| 183 | values[Anum_pg_constraint_confmatchtype - 1] = CharGetDatum(foreignMatchType); |
| 184 | values[Anum_pg_constraint_conislocal - 1] = BoolGetDatum(conIsLocal); |
| 185 | values[Anum_pg_constraint_coninhcount - 1] = Int32GetDatum(conInhCount); |
| 186 | values[Anum_pg_constraint_connoinherit - 1] = BoolGetDatum(conNoInherit); |
| 187 | |
| 188 | if (conkeyArray) |
| 189 | values[Anum_pg_constraint_conkey - 1] = PointerGetDatum(conkeyArray); |
| 190 | else |
| 191 | nulls[Anum_pg_constraint_conkey - 1] = true; |
| 192 | |
| 193 | if (confkeyArray) |
| 194 | values[Anum_pg_constraint_confkey - 1] = PointerGetDatum(confkeyArray); |
| 195 | else |
| 196 | nulls[Anum_pg_constraint_confkey - 1] = true; |
| 197 | |
| 198 | if (conpfeqopArray) |
| 199 | values[Anum_pg_constraint_conpfeqop - 1] = PointerGetDatum(conpfeqopArray); |
| 200 | else |
| 201 | nulls[Anum_pg_constraint_conpfeqop - 1] = true; |
| 202 | |
| 203 | if (conppeqopArray) |
| 204 | values[Anum_pg_constraint_conppeqop - 1] = PointerGetDatum(conppeqopArray); |
| 205 | else |
| 206 | nulls[Anum_pg_constraint_conppeqop - 1] = true; |
| 207 | |
| 208 | if (conffeqopArray) |
| 209 | values[Anum_pg_constraint_conffeqop - 1] = PointerGetDatum(conffeqopArray); |
| 210 | else |
| 211 | nulls[Anum_pg_constraint_conffeqop - 1] = true; |
| 212 | |
| 213 | if (conexclopArray) |
| 214 | values[Anum_pg_constraint_conexclop - 1] = PointerGetDatum(conexclopArray); |
| 215 | else |
| 216 | nulls[Anum_pg_constraint_conexclop - 1] = true; |
| 217 | |
| 218 | if (conBin) |
| 219 | values[Anum_pg_constraint_conbin - 1] = CStringGetTextDatum(conBin); |
| 220 | else |
| 221 | nulls[Anum_pg_constraint_conbin - 1] = true; |
| 222 | |
| 223 | tup = heap_form_tuple(RelationGetDescr(conDesc), values, nulls); |
| 224 | |
| 225 | CatalogTupleInsert(conDesc, tup); |
| 226 | |
| 227 | conobject.classId = ConstraintRelationId; |
| 228 | conobject.objectId = conOid; |
| 229 | conobject.objectSubId = 0; |
| 230 | |
| 231 | table_close(conDesc, RowExclusiveLock); |
| 232 | |
| 233 | if (OidIsValid(relId)) |
| 234 | { |
| 235 | /* |
| 236 | * Register auto dependency from constraint to owning relation, or to |
| 237 | * specific column(s) if any are mentioned. |
| 238 | */ |
| 239 | ObjectAddress relobject; |
| 240 | |
| 241 | relobject.classId = RelationRelationId; |
| 242 | relobject.objectId = relId; |
| 243 | if (constraintNTotalKeys > 0) |
| 244 | { |
| 245 | for (i = 0; i < constraintNTotalKeys; i++) |
| 246 | { |
| 247 | relobject.objectSubId = constraintKey[i]; |
| 248 | |
| 249 | recordDependencyOn(&conobject, &relobject, DEPENDENCY_AUTO); |
| 250 | } |
| 251 | } |
| 252 | else |
| 253 | { |
| 254 | relobject.objectSubId = 0; |
| 255 | |
| 256 | recordDependencyOn(&conobject, &relobject, DEPENDENCY_AUTO); |
| 257 | } |
| 258 | } |
| 259 | |
| 260 | if (OidIsValid(domainId)) |
| 261 | { |
| 262 | /* |
| 263 | * Register auto dependency from constraint to owning domain |
| 264 | */ |
| 265 | ObjectAddress domobject; |
| 266 | |
| 267 | domobject.classId = TypeRelationId; |
| 268 | domobject.objectId = domainId; |
| 269 | domobject.objectSubId = 0; |
| 270 | |
| 271 | recordDependencyOn(&conobject, &domobject, DEPENDENCY_AUTO); |
| 272 | } |
| 273 | |
| 274 | if (OidIsValid(foreignRelId)) |
| 275 | { |
| 276 | /* |
| 277 | * Register normal dependency from constraint to foreign relation, or |
| 278 | * to specific column(s) if any are mentioned. |
| 279 | */ |
| 280 | ObjectAddress relobject; |
| 281 | |
| 282 | relobject.classId = RelationRelationId; |
| 283 | relobject.objectId = foreignRelId; |
| 284 | if (foreignNKeys > 0) |
| 285 | { |
| 286 | for (i = 0; i < foreignNKeys; i++) |
| 287 | { |
| 288 | relobject.objectSubId = foreignKey[i]; |
| 289 | |
| 290 | recordDependencyOn(&conobject, &relobject, DEPENDENCY_NORMAL); |
| 291 | } |
| 292 | } |
| 293 | else |
| 294 | { |
| 295 | relobject.objectSubId = 0; |
| 296 | |
| 297 | recordDependencyOn(&conobject, &relobject, DEPENDENCY_NORMAL); |
| 298 | } |
| 299 | } |
| 300 | |
| 301 | if (OidIsValid(indexRelId) && constraintType == CONSTRAINT_FOREIGN) |
| 302 | { |
| 303 | /* |
| 304 | * Register normal dependency on the unique index that supports a |
| 305 | * foreign-key constraint. (Note: for indexes associated with unique |
| 306 | * or primary-key constraints, the dependency runs the other way, and |
| 307 | * is not made here.) |
| 308 | */ |
| 309 | ObjectAddress relobject; |
| 310 | |
| 311 | relobject.classId = RelationRelationId; |
| 312 | relobject.objectId = indexRelId; |
| 313 | relobject.objectSubId = 0; |
| 314 | |
| 315 | recordDependencyOn(&conobject, &relobject, DEPENDENCY_NORMAL); |
| 316 | } |
| 317 | |
| 318 | if (foreignNKeys > 0) |
| 319 | { |
| 320 | /* |
| 321 | * Register normal dependencies on the equality operators that support |
| 322 | * a foreign-key constraint. If the PK and FK types are the same then |
| 323 | * all three operators for a column are the same; otherwise they are |
| 324 | * different. |
| 325 | */ |
| 326 | ObjectAddress oprobject; |
| 327 | |
| 328 | oprobject.classId = OperatorRelationId; |
| 329 | oprobject.objectSubId = 0; |
| 330 | |
| 331 | for (i = 0; i < foreignNKeys; i++) |
| 332 | { |
| 333 | oprobject.objectId = pfEqOp[i]; |
| 334 | recordDependencyOn(&conobject, &oprobject, DEPENDENCY_NORMAL); |
| 335 | if (ppEqOp[i] != pfEqOp[i]) |
| 336 | { |
| 337 | oprobject.objectId = ppEqOp[i]; |
| 338 | recordDependencyOn(&conobject, &oprobject, DEPENDENCY_NORMAL); |
| 339 | } |
| 340 | if (ffEqOp[i] != pfEqOp[i]) |
| 341 | { |
| 342 | oprobject.objectId = ffEqOp[i]; |
| 343 | recordDependencyOn(&conobject, &oprobject, DEPENDENCY_NORMAL); |
| 344 | } |
| 345 | } |
| 346 | } |
| 347 | |
| 348 | /* |
| 349 | * We don't bother to register dependencies on the exclusion operators of |
| 350 | * an exclusion constraint. We assume they are members of the opclass |
| 351 | * supporting the index, so there's an indirect dependency via that. (This |
| 352 | * would be pretty dicey for cross-type operators, but exclusion operators |
| 353 | * can never be cross-type.) |
| 354 | */ |
| 355 | |
| 356 | if (conExpr != NULL) |
| 357 | { |
| 358 | /* |
| 359 | * Register dependencies from constraint to objects mentioned in CHECK |
| 360 | * expression. |
| 361 | */ |
| 362 | recordDependencyOnSingleRelExpr(&conobject, conExpr, relId, |
| 363 | DEPENDENCY_NORMAL, |
| 364 | DEPENDENCY_NORMAL, false); |
| 365 | } |
| 366 | |
| 367 | /* Post creation hook for new constraint */ |
| 368 | InvokeObjectPostCreateHookArg(ConstraintRelationId, conOid, 0, |
| 369 | is_internal); |
| 370 | |
| 371 | return conOid; |
| 372 | } |
| 373 | |
| 374 | /* |
| 375 | * Test whether given name is currently used as a constraint name |
| 376 | * for the given object (relation or domain). |
| 377 | * |
| 378 | * This is used to decide whether to accept a user-specified constraint name. |
| 379 | * It is deliberately not the same test as ChooseConstraintName uses to decide |
| 380 | * whether an auto-generated name is OK: here, we will allow it unless there |
| 381 | * is an identical constraint name in use *on the same object*. |
| 382 | * |
| 383 | * NB: Caller should hold exclusive lock on the given object, else |
| 384 | * this test can be fooled by concurrent additions. |
| 385 | */ |
| 386 | bool |
| 387 | ConstraintNameIsUsed(ConstraintCategory conCat, Oid objId, |
| 388 | const char *conname) |
| 389 | { |
| 390 | bool found; |
| 391 | Relation conDesc; |
| 392 | SysScanDesc conscan; |
| 393 | ScanKeyData skey[3]; |
| 394 | |
| 395 | conDesc = table_open(ConstraintRelationId, AccessShareLock); |
| 396 | |
| 397 | ScanKeyInit(&skey[0], |
| 398 | Anum_pg_constraint_conrelid, |
| 399 | BTEqualStrategyNumber, F_OIDEQ, |
| 400 | ObjectIdGetDatum((conCat == CONSTRAINT_RELATION) |
| 401 | ? objId : InvalidOid)); |
| 402 | ScanKeyInit(&skey[1], |
| 403 | Anum_pg_constraint_contypid, |
| 404 | BTEqualStrategyNumber, F_OIDEQ, |
| 405 | ObjectIdGetDatum((conCat == CONSTRAINT_DOMAIN) |
| 406 | ? objId : InvalidOid)); |
| 407 | ScanKeyInit(&skey[2], |
| 408 | Anum_pg_constraint_conname, |
| 409 | BTEqualStrategyNumber, F_NAMEEQ, |
| 410 | CStringGetDatum(conname)); |
| 411 | |
| 412 | conscan = systable_beginscan(conDesc, ConstraintRelidTypidNameIndexId, |
| 413 | true, NULL, 3, skey); |
| 414 | |
| 415 | /* There can be at most one matching row */ |
| 416 | found = (HeapTupleIsValid(systable_getnext(conscan))); |
| 417 | |
| 418 | systable_endscan(conscan); |
| 419 | table_close(conDesc, AccessShareLock); |
| 420 | |
| 421 | return found; |
| 422 | } |
| 423 | |
| 424 | /* |
| 425 | * Does any constraint of the given name exist in the given namespace? |
| 426 | * |
| 427 | * This is used for code that wants to match ChooseConstraintName's rule |
| 428 | * that we should avoid autogenerating duplicate constraint names within a |
| 429 | * namespace. |
| 430 | */ |
| 431 | bool |
| 432 | ConstraintNameExists(const char *conname, Oid namespaceid) |
| 433 | { |
| 434 | bool found; |
| 435 | Relation conDesc; |
| 436 | SysScanDesc conscan; |
| 437 | ScanKeyData skey[2]; |
| 438 | |
| 439 | conDesc = table_open(ConstraintRelationId, AccessShareLock); |
| 440 | |
| 441 | ScanKeyInit(&skey[0], |
| 442 | Anum_pg_constraint_conname, |
| 443 | BTEqualStrategyNumber, F_NAMEEQ, |
| 444 | CStringGetDatum(conname)); |
| 445 | |
| 446 | ScanKeyInit(&skey[1], |
| 447 | Anum_pg_constraint_connamespace, |
| 448 | BTEqualStrategyNumber, F_OIDEQ, |
| 449 | ObjectIdGetDatum(namespaceid)); |
| 450 | |
| 451 | conscan = systable_beginscan(conDesc, ConstraintNameNspIndexId, true, |
| 452 | NULL, 2, skey); |
| 453 | |
| 454 | found = (HeapTupleIsValid(systable_getnext(conscan))); |
| 455 | |
| 456 | systable_endscan(conscan); |
| 457 | table_close(conDesc, AccessShareLock); |
| 458 | |
| 459 | return found; |
| 460 | } |
| 461 | |
| 462 | /* |
| 463 | * Select a nonconflicting name for a new constraint. |
| 464 | * |
| 465 | * The objective here is to choose a name that is unique within the |
| 466 | * specified namespace. Postgres does not require this, but the SQL |
| 467 | * spec does, and some apps depend on it. Therefore we avoid choosing |
| 468 | * default names that so conflict. |
| 469 | * |
| 470 | * name1, name2, and label are used the same way as for makeObjectName(), |
| 471 | * except that the label can't be NULL; digits will be appended to the label |
| 472 | * if needed to create a name that is unique within the specified namespace. |
| 473 | * |
| 474 | * 'others' can be a list of string names already chosen within the current |
| 475 | * command (but not yet reflected into the catalogs); we will not choose |
| 476 | * a duplicate of one of these either. |
| 477 | * |
| 478 | * Note: it is theoretically possible to get a collision anyway, if someone |
| 479 | * else chooses the same name concurrently. This is fairly unlikely to be |
| 480 | * a problem in practice, especially if one is holding an exclusive lock on |
| 481 | * the relation identified by name1. |
| 482 | * |
| 483 | * Returns a palloc'd string. |
| 484 | */ |
| 485 | char * |
| 486 | ChooseConstraintName(const char *name1, const char *name2, |
| 487 | const char *label, Oid namespaceid, |
| 488 | List *others) |
| 489 | { |
| 490 | int pass = 0; |
| 491 | char *conname = NULL; |
| 492 | char modlabel[NAMEDATALEN]; |
| 493 | Relation conDesc; |
| 494 | SysScanDesc conscan; |
| 495 | ScanKeyData skey[2]; |
| 496 | bool found; |
| 497 | ListCell *l; |
| 498 | |
| 499 | conDesc = table_open(ConstraintRelationId, AccessShareLock); |
| 500 | |
| 501 | /* try the unmodified label first */ |
| 502 | StrNCpy(modlabel, label, sizeof(modlabel)); |
| 503 | |
| 504 | for (;;) |
| 505 | { |
| 506 | conname = makeObjectName(name1, name2, modlabel); |
| 507 | |
| 508 | found = false; |
| 509 | |
| 510 | foreach(l, others) |
| 511 | { |
| 512 | if (strcmp((char *) lfirst(l), conname) == 0) |
| 513 | { |
| 514 | found = true; |
| 515 | break; |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | if (!found) |
| 520 | { |
| 521 | ScanKeyInit(&skey[0], |
| 522 | Anum_pg_constraint_conname, |
| 523 | BTEqualStrategyNumber, F_NAMEEQ, |
| 524 | CStringGetDatum(conname)); |
| 525 | |
| 526 | ScanKeyInit(&skey[1], |
| 527 | Anum_pg_constraint_connamespace, |
| 528 | BTEqualStrategyNumber, F_OIDEQ, |
| 529 | ObjectIdGetDatum(namespaceid)); |
| 530 | |
| 531 | conscan = systable_beginscan(conDesc, ConstraintNameNspIndexId, true, |
| 532 | NULL, 2, skey); |
| 533 | |
| 534 | found = (HeapTupleIsValid(systable_getnext(conscan))); |
| 535 | |
| 536 | systable_endscan(conscan); |
| 537 | } |
| 538 | |
| 539 | if (!found) |
| 540 | break; |
| 541 | |
| 542 | /* found a conflict, so try a new name component */ |
| 543 | pfree(conname); |
| 544 | snprintf(modlabel, sizeof(modlabel), "%s%d" , label, ++pass); |
| 545 | } |
| 546 | |
| 547 | table_close(conDesc, AccessShareLock); |
| 548 | |
| 549 | return conname; |
| 550 | } |
| 551 | |
| 552 | /* |
| 553 | * Delete a single constraint record. |
| 554 | */ |
| 555 | void |
| 556 | RemoveConstraintById(Oid conId) |
| 557 | { |
| 558 | Relation conDesc; |
| 559 | HeapTuple tup; |
| 560 | Form_pg_constraint con; |
| 561 | |
| 562 | conDesc = table_open(ConstraintRelationId, RowExclusiveLock); |
| 563 | |
| 564 | tup = SearchSysCache1(CONSTROID, ObjectIdGetDatum(conId)); |
| 565 | if (!HeapTupleIsValid(tup)) /* should not happen */ |
| 566 | elog(ERROR, "cache lookup failed for constraint %u" , conId); |
| 567 | con = (Form_pg_constraint) GETSTRUCT(tup); |
| 568 | |
| 569 | /* |
| 570 | * Special processing depending on what the constraint is for. |
| 571 | */ |
| 572 | if (OidIsValid(con->conrelid)) |
| 573 | { |
| 574 | Relation rel; |
| 575 | |
| 576 | /* |
| 577 | * If the constraint is for a relation, open and exclusive-lock the |
| 578 | * relation it's for. |
| 579 | */ |
| 580 | rel = table_open(con->conrelid, AccessExclusiveLock); |
| 581 | |
| 582 | /* |
| 583 | * We need to update the relcheck count if it is a check constraint |
| 584 | * being dropped. This update will force backends to rebuild relcache |
| 585 | * entries when we commit. |
| 586 | */ |
| 587 | if (con->contype == CONSTRAINT_CHECK) |
| 588 | { |
| 589 | Relation pgrel; |
| 590 | HeapTuple relTup; |
| 591 | Form_pg_class classForm; |
| 592 | |
| 593 | pgrel = table_open(RelationRelationId, RowExclusiveLock); |
| 594 | relTup = SearchSysCacheCopy1(RELOID, |
| 595 | ObjectIdGetDatum(con->conrelid)); |
| 596 | if (!HeapTupleIsValid(relTup)) |
| 597 | elog(ERROR, "cache lookup failed for relation %u" , |
| 598 | con->conrelid); |
| 599 | classForm = (Form_pg_class) GETSTRUCT(relTup); |
| 600 | |
| 601 | if (classForm->relchecks == 0) /* should not happen */ |
| 602 | elog(ERROR, "relation \"%s\" has relchecks = 0" , |
| 603 | RelationGetRelationName(rel)); |
| 604 | classForm->relchecks--; |
| 605 | |
| 606 | CatalogTupleUpdate(pgrel, &relTup->t_self, relTup); |
| 607 | |
| 608 | heap_freetuple(relTup); |
| 609 | |
| 610 | table_close(pgrel, RowExclusiveLock); |
| 611 | } |
| 612 | |
| 613 | /* Keep lock on constraint's rel until end of xact */ |
| 614 | table_close(rel, NoLock); |
| 615 | } |
| 616 | else if (OidIsValid(con->contypid)) |
| 617 | { |
| 618 | /* |
| 619 | * XXX for now, do nothing special when dropping a domain constraint |
| 620 | * |
| 621 | * Probably there should be some form of locking on the domain type, |
| 622 | * but we have no such concept at the moment. |
| 623 | */ |
| 624 | } |
| 625 | else |
| 626 | elog(ERROR, "constraint %u is not of a known type" , conId); |
| 627 | |
| 628 | /* Fry the constraint itself */ |
| 629 | CatalogTupleDelete(conDesc, &tup->t_self); |
| 630 | |
| 631 | /* Clean up */ |
| 632 | ReleaseSysCache(tup); |
| 633 | table_close(conDesc, RowExclusiveLock); |
| 634 | } |
| 635 | |
| 636 | /* |
| 637 | * RenameConstraintById |
| 638 | * Rename a constraint. |
| 639 | * |
| 640 | * Note: this isn't intended to be a user-exposed function; it doesn't check |
| 641 | * permissions etc. Currently this is only invoked when renaming an index |
| 642 | * that is associated with a constraint, but it's made a little more general |
| 643 | * than that with the expectation of someday having ALTER TABLE RENAME |
| 644 | * CONSTRAINT. |
| 645 | */ |
| 646 | void |
| 647 | RenameConstraintById(Oid conId, const char *newname) |
| 648 | { |
| 649 | Relation conDesc; |
| 650 | HeapTuple tuple; |
| 651 | Form_pg_constraint con; |
| 652 | |
| 653 | conDesc = table_open(ConstraintRelationId, RowExclusiveLock); |
| 654 | |
| 655 | tuple = SearchSysCacheCopy1(CONSTROID, ObjectIdGetDatum(conId)); |
| 656 | if (!HeapTupleIsValid(tuple)) |
| 657 | elog(ERROR, "cache lookup failed for constraint %u" , conId); |
| 658 | con = (Form_pg_constraint) GETSTRUCT(tuple); |
| 659 | |
| 660 | /* |
| 661 | * For user-friendliness, check whether the name is already in use. |
| 662 | */ |
| 663 | if (OidIsValid(con->conrelid) && |
| 664 | ConstraintNameIsUsed(CONSTRAINT_RELATION, |
| 665 | con->conrelid, |
| 666 | newname)) |
| 667 | ereport(ERROR, |
| 668 | (errcode(ERRCODE_DUPLICATE_OBJECT), |
| 669 | errmsg("constraint \"%s\" for relation \"%s\" already exists" , |
| 670 | newname, get_rel_name(con->conrelid)))); |
| 671 | if (OidIsValid(con->contypid) && |
| 672 | ConstraintNameIsUsed(CONSTRAINT_DOMAIN, |
| 673 | con->contypid, |
| 674 | newname)) |
| 675 | ereport(ERROR, |
| 676 | (errcode(ERRCODE_DUPLICATE_OBJECT), |
| 677 | errmsg("constraint \"%s\" for domain %s already exists" , |
| 678 | newname, format_type_be(con->contypid)))); |
| 679 | |
| 680 | /* OK, do the rename --- tuple is a copy, so OK to scribble on it */ |
| 681 | namestrcpy(&(con->conname), newname); |
| 682 | |
| 683 | CatalogTupleUpdate(conDesc, &tuple->t_self, tuple); |
| 684 | |
| 685 | InvokeObjectPostAlterHook(ConstraintRelationId, conId, 0); |
| 686 | |
| 687 | heap_freetuple(tuple); |
| 688 | table_close(conDesc, RowExclusiveLock); |
| 689 | } |
| 690 | |
| 691 | /* |
| 692 | * AlterConstraintNamespaces |
| 693 | * Find any constraints belonging to the specified object, |
| 694 | * and move them to the specified new namespace. |
| 695 | * |
| 696 | * isType indicates whether the owning object is a type or a relation. |
| 697 | */ |
| 698 | void |
| 699 | AlterConstraintNamespaces(Oid ownerId, Oid oldNspId, |
| 700 | Oid newNspId, bool isType, ObjectAddresses *objsMoved) |
| 701 | { |
| 702 | Relation conRel; |
| 703 | ScanKeyData key[2]; |
| 704 | SysScanDesc scan; |
| 705 | HeapTuple tup; |
| 706 | |
| 707 | conRel = table_open(ConstraintRelationId, RowExclusiveLock); |
| 708 | |
| 709 | ScanKeyInit(&key[0], |
| 710 | Anum_pg_constraint_conrelid, |
| 711 | BTEqualStrategyNumber, F_OIDEQ, |
| 712 | ObjectIdGetDatum(isType ? InvalidOid : ownerId)); |
| 713 | ScanKeyInit(&key[1], |
| 714 | Anum_pg_constraint_contypid, |
| 715 | BTEqualStrategyNumber, F_OIDEQ, |
| 716 | ObjectIdGetDatum(isType ? ownerId : InvalidOid)); |
| 717 | |
| 718 | scan = systable_beginscan(conRel, ConstraintRelidTypidNameIndexId, true, |
| 719 | NULL, 2, key); |
| 720 | |
| 721 | while (HeapTupleIsValid((tup = systable_getnext(scan)))) |
| 722 | { |
| 723 | Form_pg_constraint conform = (Form_pg_constraint) GETSTRUCT(tup); |
| 724 | ObjectAddress thisobj; |
| 725 | |
| 726 | thisobj.classId = ConstraintRelationId; |
| 727 | thisobj.objectId = conform->oid; |
| 728 | thisobj.objectSubId = 0; |
| 729 | |
| 730 | if (object_address_present(&thisobj, objsMoved)) |
| 731 | continue; |
| 732 | |
| 733 | /* Don't update if the object is already part of the namespace */ |
| 734 | if (conform->connamespace == oldNspId && oldNspId != newNspId) |
| 735 | { |
| 736 | tup = heap_copytuple(tup); |
| 737 | conform = (Form_pg_constraint) GETSTRUCT(tup); |
| 738 | |
| 739 | conform->connamespace = newNspId; |
| 740 | |
| 741 | CatalogTupleUpdate(conRel, &tup->t_self, tup); |
| 742 | |
| 743 | /* |
| 744 | * Note: currently, the constraint will not have its own |
| 745 | * dependency on the namespace, so we don't need to do |
| 746 | * changeDependencyFor(). |
| 747 | */ |
| 748 | } |
| 749 | |
| 750 | InvokeObjectPostAlterHook(ConstraintRelationId, thisobj.objectId, 0); |
| 751 | |
| 752 | add_exact_object_address(&thisobj, objsMoved); |
| 753 | } |
| 754 | |
| 755 | systable_endscan(scan); |
| 756 | |
| 757 | table_close(conRel, RowExclusiveLock); |
| 758 | } |
| 759 | |
| 760 | /* |
| 761 | * ConstraintSetParentConstraint |
| 762 | * Set a partition's constraint as child of its parent constraint, |
| 763 | * or remove the linkage if parentConstrId is InvalidOid. |
| 764 | * |
| 765 | * This updates the constraint's pg_constraint row to show it as inherited, and |
| 766 | * adds PARTITION dependencies to prevent the constraint from being deleted |
| 767 | * on its own. Alternatively, reverse that. |
| 768 | */ |
| 769 | void |
| 770 | ConstraintSetParentConstraint(Oid childConstrId, |
| 771 | Oid parentConstrId, |
| 772 | Oid childTableId) |
| 773 | { |
| 774 | Relation constrRel; |
| 775 | Form_pg_constraint constrForm; |
| 776 | HeapTuple tuple, |
| 777 | newtup; |
| 778 | ObjectAddress depender; |
| 779 | ObjectAddress referenced; |
| 780 | |
| 781 | constrRel = table_open(ConstraintRelationId, RowExclusiveLock); |
| 782 | tuple = SearchSysCache1(CONSTROID, ObjectIdGetDatum(childConstrId)); |
| 783 | if (!HeapTupleIsValid(tuple)) |
| 784 | elog(ERROR, "cache lookup failed for constraint %u" , childConstrId); |
| 785 | newtup = heap_copytuple(tuple); |
| 786 | constrForm = (Form_pg_constraint) GETSTRUCT(newtup); |
| 787 | if (OidIsValid(parentConstrId)) |
| 788 | { |
| 789 | /* don't allow setting parent for a constraint that already has one */ |
| 790 | Assert(constrForm->coninhcount == 0); |
| 791 | if (constrForm->conparentid != InvalidOid) |
| 792 | elog(ERROR, "constraint %u already has a parent constraint" , |
| 793 | childConstrId); |
| 794 | |
| 795 | constrForm->conislocal = false; |
| 796 | constrForm->coninhcount++; |
| 797 | constrForm->conparentid = parentConstrId; |
| 798 | |
| 799 | CatalogTupleUpdate(constrRel, &tuple->t_self, newtup); |
| 800 | |
| 801 | ObjectAddressSet(depender, ConstraintRelationId, childConstrId); |
| 802 | |
| 803 | ObjectAddressSet(referenced, ConstraintRelationId, parentConstrId); |
| 804 | recordDependencyOn(&depender, &referenced, DEPENDENCY_PARTITION_PRI); |
| 805 | |
| 806 | ObjectAddressSet(referenced, RelationRelationId, childTableId); |
| 807 | recordDependencyOn(&depender, &referenced, DEPENDENCY_PARTITION_SEC); |
| 808 | } |
| 809 | else |
| 810 | { |
| 811 | constrForm->coninhcount--; |
| 812 | constrForm->conislocal = true; |
| 813 | constrForm->conparentid = InvalidOid; |
| 814 | |
| 815 | /* Make sure there's no further inheritance. */ |
| 816 | Assert(constrForm->coninhcount == 0); |
| 817 | |
| 818 | CatalogTupleUpdate(constrRel, &tuple->t_self, newtup); |
| 819 | |
| 820 | deleteDependencyRecordsForClass(ConstraintRelationId, childConstrId, |
| 821 | ConstraintRelationId, |
| 822 | DEPENDENCY_PARTITION_PRI); |
| 823 | deleteDependencyRecordsForClass(ConstraintRelationId, childConstrId, |
| 824 | RelationRelationId, |
| 825 | DEPENDENCY_PARTITION_SEC); |
| 826 | } |
| 827 | |
| 828 | ReleaseSysCache(tuple); |
| 829 | table_close(constrRel, RowExclusiveLock); |
| 830 | } |
| 831 | |
| 832 | |
| 833 | /* |
| 834 | * get_relation_constraint_oid |
| 835 | * Find a constraint on the specified relation with the specified name. |
| 836 | * Returns constraint's OID. |
| 837 | */ |
| 838 | Oid |
| 839 | get_relation_constraint_oid(Oid relid, const char *conname, bool missing_ok) |
| 840 | { |
| 841 | Relation pg_constraint; |
| 842 | HeapTuple tuple; |
| 843 | SysScanDesc scan; |
| 844 | ScanKeyData skey[3]; |
| 845 | Oid conOid = InvalidOid; |
| 846 | |
| 847 | pg_constraint = table_open(ConstraintRelationId, AccessShareLock); |
| 848 | |
| 849 | ScanKeyInit(&skey[0], |
| 850 | Anum_pg_constraint_conrelid, |
| 851 | BTEqualStrategyNumber, F_OIDEQ, |
| 852 | ObjectIdGetDatum(relid)); |
| 853 | ScanKeyInit(&skey[1], |
| 854 | Anum_pg_constraint_contypid, |
| 855 | BTEqualStrategyNumber, F_OIDEQ, |
| 856 | ObjectIdGetDatum(InvalidOid)); |
| 857 | ScanKeyInit(&skey[2], |
| 858 | Anum_pg_constraint_conname, |
| 859 | BTEqualStrategyNumber, F_NAMEEQ, |
| 860 | CStringGetDatum(conname)); |
| 861 | |
| 862 | scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId, true, |
| 863 | NULL, 3, skey); |
| 864 | |
| 865 | /* There can be at most one matching row */ |
| 866 | if (HeapTupleIsValid(tuple = systable_getnext(scan))) |
| 867 | conOid = ((Form_pg_constraint) GETSTRUCT(tuple))->oid; |
| 868 | |
| 869 | systable_endscan(scan); |
| 870 | |
| 871 | /* If no such constraint exists, complain */ |
| 872 | if (!OidIsValid(conOid) && !missing_ok) |
| 873 | ereport(ERROR, |
| 874 | (errcode(ERRCODE_UNDEFINED_OBJECT), |
| 875 | errmsg("constraint \"%s\" for table \"%s\" does not exist" , |
| 876 | conname, get_rel_name(relid)))); |
| 877 | |
| 878 | table_close(pg_constraint, AccessShareLock); |
| 879 | |
| 880 | return conOid; |
| 881 | } |
| 882 | |
| 883 | /* |
| 884 | * get_relation_constraint_attnos |
| 885 | * Find a constraint on the specified relation with the specified name |
| 886 | * and return the constrained columns. |
| 887 | * |
| 888 | * Returns a Bitmapset of the column attnos of the constrained columns, with |
| 889 | * attnos being offset by FirstLowInvalidHeapAttributeNumber so that system |
| 890 | * columns can be represented. |
| 891 | * |
| 892 | * *constraintOid is set to the OID of the constraint, or InvalidOid on |
| 893 | * failure. |
| 894 | */ |
| 895 | Bitmapset * |
| 896 | get_relation_constraint_attnos(Oid relid, const char *conname, |
| 897 | bool missing_ok, Oid *constraintOid) |
| 898 | { |
| 899 | Bitmapset *conattnos = NULL; |
| 900 | Relation pg_constraint; |
| 901 | HeapTuple tuple; |
| 902 | SysScanDesc scan; |
| 903 | ScanKeyData skey[3]; |
| 904 | |
| 905 | /* Set *constraintOid, to avoid complaints about uninitialized vars */ |
| 906 | *constraintOid = InvalidOid; |
| 907 | |
| 908 | pg_constraint = table_open(ConstraintRelationId, AccessShareLock); |
| 909 | |
| 910 | ScanKeyInit(&skey[0], |
| 911 | Anum_pg_constraint_conrelid, |
| 912 | BTEqualStrategyNumber, F_OIDEQ, |
| 913 | ObjectIdGetDatum(relid)); |
| 914 | ScanKeyInit(&skey[1], |
| 915 | Anum_pg_constraint_contypid, |
| 916 | BTEqualStrategyNumber, F_OIDEQ, |
| 917 | ObjectIdGetDatum(InvalidOid)); |
| 918 | ScanKeyInit(&skey[2], |
| 919 | Anum_pg_constraint_conname, |
| 920 | BTEqualStrategyNumber, F_NAMEEQ, |
| 921 | CStringGetDatum(conname)); |
| 922 | |
| 923 | scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId, true, |
| 924 | NULL, 3, skey); |
| 925 | |
| 926 | /* There can be at most one matching row */ |
| 927 | if (HeapTupleIsValid(tuple = systable_getnext(scan))) |
| 928 | { |
| 929 | Datum adatum; |
| 930 | bool isNull; |
| 931 | |
| 932 | *constraintOid = ((Form_pg_constraint) GETSTRUCT(tuple))->oid; |
| 933 | |
| 934 | /* Extract the conkey array, ie, attnums of constrained columns */ |
| 935 | adatum = heap_getattr(tuple, Anum_pg_constraint_conkey, |
| 936 | RelationGetDescr(pg_constraint), &isNull); |
| 937 | if (!isNull) |
| 938 | { |
| 939 | ArrayType *arr; |
| 940 | int numcols; |
| 941 | int16 *attnums; |
| 942 | int i; |
| 943 | |
| 944 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 945 | numcols = ARR_DIMS(arr)[0]; |
| 946 | if (ARR_NDIM(arr) != 1 || |
| 947 | numcols < 0 || |
| 948 | ARR_HASNULL(arr) || |
| 949 | ARR_ELEMTYPE(arr) != INT2OID) |
| 950 | elog(ERROR, "conkey is not a 1-D smallint array" ); |
| 951 | attnums = (int16 *) ARR_DATA_PTR(arr); |
| 952 | |
| 953 | /* Construct the result value */ |
| 954 | for (i = 0; i < numcols; i++) |
| 955 | { |
| 956 | conattnos = bms_add_member(conattnos, |
| 957 | attnums[i] - FirstLowInvalidHeapAttributeNumber); |
| 958 | } |
| 959 | } |
| 960 | } |
| 961 | |
| 962 | systable_endscan(scan); |
| 963 | |
| 964 | /* If no such constraint exists, complain */ |
| 965 | if (!OidIsValid(*constraintOid) && !missing_ok) |
| 966 | ereport(ERROR, |
| 967 | (errcode(ERRCODE_UNDEFINED_OBJECT), |
| 968 | errmsg("constraint \"%s\" for table \"%s\" does not exist" , |
| 969 | conname, get_rel_name(relid)))); |
| 970 | |
| 971 | table_close(pg_constraint, AccessShareLock); |
| 972 | |
| 973 | return conattnos; |
| 974 | } |
| 975 | |
| 976 | /* |
| 977 | * Return the OID of the constraint associated with the given index in the |
| 978 | * given relation; or InvalidOid if no such index is catalogued. |
| 979 | */ |
| 980 | Oid |
| 981 | get_relation_idx_constraint_oid(Oid relationId, Oid indexId) |
| 982 | { |
| 983 | Relation pg_constraint; |
| 984 | SysScanDesc scan; |
| 985 | ScanKeyData key; |
| 986 | HeapTuple tuple; |
| 987 | Oid constraintId = InvalidOid; |
| 988 | |
| 989 | pg_constraint = table_open(ConstraintRelationId, AccessShareLock); |
| 990 | |
| 991 | ScanKeyInit(&key, |
| 992 | Anum_pg_constraint_conrelid, |
| 993 | BTEqualStrategyNumber, |
| 994 | F_OIDEQ, |
| 995 | ObjectIdGetDatum(relationId)); |
| 996 | scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId, |
| 997 | true, NULL, 1, &key); |
| 998 | while ((tuple = systable_getnext(scan)) != NULL) |
| 999 | { |
| 1000 | Form_pg_constraint constrForm; |
| 1001 | |
| 1002 | constrForm = (Form_pg_constraint) GETSTRUCT(tuple); |
| 1003 | if (constrForm->conindid == indexId) |
| 1004 | { |
| 1005 | constraintId = constrForm->oid; |
| 1006 | break; |
| 1007 | } |
| 1008 | } |
| 1009 | systable_endscan(scan); |
| 1010 | |
| 1011 | table_close(pg_constraint, AccessShareLock); |
| 1012 | return constraintId; |
| 1013 | } |
| 1014 | |
| 1015 | /* |
| 1016 | * get_domain_constraint_oid |
| 1017 | * Find a constraint on the specified domain with the specified name. |
| 1018 | * Returns constraint's OID. |
| 1019 | */ |
| 1020 | Oid |
| 1021 | get_domain_constraint_oid(Oid typid, const char *conname, bool missing_ok) |
| 1022 | { |
| 1023 | Relation pg_constraint; |
| 1024 | HeapTuple tuple; |
| 1025 | SysScanDesc scan; |
| 1026 | ScanKeyData skey[3]; |
| 1027 | Oid conOid = InvalidOid; |
| 1028 | |
| 1029 | pg_constraint = table_open(ConstraintRelationId, AccessShareLock); |
| 1030 | |
| 1031 | ScanKeyInit(&skey[0], |
| 1032 | Anum_pg_constraint_conrelid, |
| 1033 | BTEqualStrategyNumber, F_OIDEQ, |
| 1034 | ObjectIdGetDatum(InvalidOid)); |
| 1035 | ScanKeyInit(&skey[1], |
| 1036 | Anum_pg_constraint_contypid, |
| 1037 | BTEqualStrategyNumber, F_OIDEQ, |
| 1038 | ObjectIdGetDatum(typid)); |
| 1039 | ScanKeyInit(&skey[2], |
| 1040 | Anum_pg_constraint_conname, |
| 1041 | BTEqualStrategyNumber, F_NAMEEQ, |
| 1042 | CStringGetDatum(conname)); |
| 1043 | |
| 1044 | scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId, true, |
| 1045 | NULL, 3, skey); |
| 1046 | |
| 1047 | /* There can be at most one matching row */ |
| 1048 | if (HeapTupleIsValid(tuple = systable_getnext(scan))) |
| 1049 | conOid = ((Form_pg_constraint) GETSTRUCT(tuple))->oid; |
| 1050 | |
| 1051 | systable_endscan(scan); |
| 1052 | |
| 1053 | /* If no such constraint exists, complain */ |
| 1054 | if (!OidIsValid(conOid) && !missing_ok) |
| 1055 | ereport(ERROR, |
| 1056 | (errcode(ERRCODE_UNDEFINED_OBJECT), |
| 1057 | errmsg("constraint \"%s\" for domain %s does not exist" , |
| 1058 | conname, format_type_be(typid)))); |
| 1059 | |
| 1060 | table_close(pg_constraint, AccessShareLock); |
| 1061 | |
| 1062 | return conOid; |
| 1063 | } |
| 1064 | |
| 1065 | /* |
| 1066 | * get_primary_key_attnos |
| 1067 | * Identify the columns in a relation's primary key, if any. |
| 1068 | * |
| 1069 | * Returns a Bitmapset of the column attnos of the primary key's columns, |
| 1070 | * with attnos being offset by FirstLowInvalidHeapAttributeNumber so that |
| 1071 | * system columns can be represented. |
| 1072 | * |
| 1073 | * If there is no primary key, return NULL. We also return NULL if the pkey |
| 1074 | * constraint is deferrable and deferrableOk is false. |
| 1075 | * |
| 1076 | * *constraintOid is set to the OID of the pkey constraint, or InvalidOid |
| 1077 | * on failure. |
| 1078 | */ |
| 1079 | Bitmapset * |
| 1080 | get_primary_key_attnos(Oid relid, bool deferrableOk, Oid *constraintOid) |
| 1081 | { |
| 1082 | Bitmapset *pkattnos = NULL; |
| 1083 | Relation pg_constraint; |
| 1084 | HeapTuple tuple; |
| 1085 | SysScanDesc scan; |
| 1086 | ScanKeyData skey[1]; |
| 1087 | |
| 1088 | /* Set *constraintOid, to avoid complaints about uninitialized vars */ |
| 1089 | *constraintOid = InvalidOid; |
| 1090 | |
| 1091 | /* Scan pg_constraint for constraints of the target rel */ |
| 1092 | pg_constraint = table_open(ConstraintRelationId, AccessShareLock); |
| 1093 | |
| 1094 | ScanKeyInit(&skey[0], |
| 1095 | Anum_pg_constraint_conrelid, |
| 1096 | BTEqualStrategyNumber, F_OIDEQ, |
| 1097 | ObjectIdGetDatum(relid)); |
| 1098 | |
| 1099 | scan = systable_beginscan(pg_constraint, ConstraintRelidTypidNameIndexId, true, |
| 1100 | NULL, 1, skey); |
| 1101 | |
| 1102 | while (HeapTupleIsValid(tuple = systable_getnext(scan))) |
| 1103 | { |
| 1104 | Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple); |
| 1105 | Datum adatum; |
| 1106 | bool isNull; |
| 1107 | ArrayType *arr; |
| 1108 | int16 *attnums; |
| 1109 | int numkeys; |
| 1110 | int i; |
| 1111 | |
| 1112 | /* Skip constraints that are not PRIMARY KEYs */ |
| 1113 | if (con->contype != CONSTRAINT_PRIMARY) |
| 1114 | continue; |
| 1115 | |
| 1116 | /* |
| 1117 | * If the primary key is deferrable, but we've been instructed to |
| 1118 | * ignore deferrable constraints, then we might as well give up |
| 1119 | * searching, since there can only be a single primary key on a table. |
| 1120 | */ |
| 1121 | if (con->condeferrable && !deferrableOk) |
| 1122 | break; |
| 1123 | |
| 1124 | /* Extract the conkey array, ie, attnums of PK's columns */ |
| 1125 | adatum = heap_getattr(tuple, Anum_pg_constraint_conkey, |
| 1126 | RelationGetDescr(pg_constraint), &isNull); |
| 1127 | if (isNull) |
| 1128 | elog(ERROR, "null conkey for constraint %u" , |
| 1129 | ((Form_pg_constraint) GETSTRUCT(tuple))->oid); |
| 1130 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 1131 | numkeys = ARR_DIMS(arr)[0]; |
| 1132 | if (ARR_NDIM(arr) != 1 || |
| 1133 | numkeys < 0 || |
| 1134 | ARR_HASNULL(arr) || |
| 1135 | ARR_ELEMTYPE(arr) != INT2OID) |
| 1136 | elog(ERROR, "conkey is not a 1-D smallint array" ); |
| 1137 | attnums = (int16 *) ARR_DATA_PTR(arr); |
| 1138 | |
| 1139 | /* Construct the result value */ |
| 1140 | for (i = 0; i < numkeys; i++) |
| 1141 | { |
| 1142 | pkattnos = bms_add_member(pkattnos, |
| 1143 | attnums[i] - FirstLowInvalidHeapAttributeNumber); |
| 1144 | } |
| 1145 | *constraintOid = ((Form_pg_constraint) GETSTRUCT(tuple))->oid; |
| 1146 | |
| 1147 | /* No need to search further */ |
| 1148 | break; |
| 1149 | } |
| 1150 | |
| 1151 | systable_endscan(scan); |
| 1152 | |
| 1153 | table_close(pg_constraint, AccessShareLock); |
| 1154 | |
| 1155 | return pkattnos; |
| 1156 | } |
| 1157 | |
| 1158 | /* |
| 1159 | * Extract data from the pg_constraint tuple of a foreign-key constraint. |
| 1160 | * |
| 1161 | * All arguments save the first are output arguments; the last three of them |
| 1162 | * can be passed as NULL if caller doesn't need them. |
| 1163 | */ |
| 1164 | void |
| 1165 | DeconstructFkConstraintRow(HeapTuple tuple, int *numfks, |
| 1166 | AttrNumber *conkey, AttrNumber *confkey, |
| 1167 | Oid *pf_eq_oprs, Oid *pp_eq_oprs, Oid *ff_eq_oprs) |
| 1168 | { |
| 1169 | Oid constrId; |
| 1170 | Datum adatum; |
| 1171 | bool isNull; |
| 1172 | ArrayType *arr; |
| 1173 | int numkeys; |
| 1174 | |
| 1175 | constrId = ((Form_pg_constraint) GETSTRUCT(tuple))->oid; |
| 1176 | |
| 1177 | /* |
| 1178 | * We expect the arrays to be 1-D arrays of the right types; verify that. |
| 1179 | * We don't need to use deconstruct_array() since the array data is just |
| 1180 | * going to look like a C array of values. |
| 1181 | */ |
| 1182 | adatum = SysCacheGetAttr(CONSTROID, tuple, |
| 1183 | Anum_pg_constraint_conkey, &isNull); |
| 1184 | if (isNull) |
| 1185 | elog(ERROR, "null conkey for constraint %u" , constrId); |
| 1186 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 1187 | if (ARR_NDIM(arr) != 1 || |
| 1188 | ARR_HASNULL(arr) || |
| 1189 | ARR_ELEMTYPE(arr) != INT2OID) |
| 1190 | elog(ERROR, "conkey is not a 1-D smallint array" ); |
| 1191 | numkeys = ARR_DIMS(arr)[0]; |
| 1192 | if (numkeys <= 0 || numkeys > INDEX_MAX_KEYS) |
| 1193 | elog(ERROR, "foreign key constraint cannot have %d columns" , numkeys); |
| 1194 | memcpy(conkey, ARR_DATA_PTR(arr), numkeys * sizeof(int16)); |
| 1195 | if ((Pointer) arr != DatumGetPointer(adatum)) |
| 1196 | pfree(arr); /* free de-toasted copy, if any */ |
| 1197 | |
| 1198 | adatum = SysCacheGetAttr(CONSTROID, tuple, |
| 1199 | Anum_pg_constraint_confkey, &isNull); |
| 1200 | if (isNull) |
| 1201 | elog(ERROR, "null confkey for constraint %u" , constrId); |
| 1202 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 1203 | if (ARR_NDIM(arr) != 1 || |
| 1204 | ARR_DIMS(arr)[0] != numkeys || |
| 1205 | ARR_HASNULL(arr) || |
| 1206 | ARR_ELEMTYPE(arr) != INT2OID) |
| 1207 | elog(ERROR, "confkey is not a 1-D smallint array" ); |
| 1208 | memcpy(confkey, ARR_DATA_PTR(arr), numkeys * sizeof(int16)); |
| 1209 | if ((Pointer) arr != DatumGetPointer(adatum)) |
| 1210 | pfree(arr); /* free de-toasted copy, if any */ |
| 1211 | |
| 1212 | if (pf_eq_oprs) |
| 1213 | { |
| 1214 | adatum = SysCacheGetAttr(CONSTROID, tuple, |
| 1215 | Anum_pg_constraint_conpfeqop, &isNull); |
| 1216 | if (isNull) |
| 1217 | elog(ERROR, "null conpfeqop for constraint %u" , constrId); |
| 1218 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 1219 | /* see TryReuseForeignKey if you change the test below */ |
| 1220 | if (ARR_NDIM(arr) != 1 || |
| 1221 | ARR_DIMS(arr)[0] != numkeys || |
| 1222 | ARR_HASNULL(arr) || |
| 1223 | ARR_ELEMTYPE(arr) != OIDOID) |
| 1224 | elog(ERROR, "conpfeqop is not a 1-D Oid array" ); |
| 1225 | memcpy(pf_eq_oprs, ARR_DATA_PTR(arr), numkeys * sizeof(Oid)); |
| 1226 | if ((Pointer) arr != DatumGetPointer(adatum)) |
| 1227 | pfree(arr); /* free de-toasted copy, if any */ |
| 1228 | } |
| 1229 | |
| 1230 | if (pp_eq_oprs) |
| 1231 | { |
| 1232 | adatum = SysCacheGetAttr(CONSTROID, tuple, |
| 1233 | Anum_pg_constraint_conppeqop, &isNull); |
| 1234 | if (isNull) |
| 1235 | elog(ERROR, "null conppeqop for constraint %u" , constrId); |
| 1236 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 1237 | if (ARR_NDIM(arr) != 1 || |
| 1238 | ARR_DIMS(arr)[0] != numkeys || |
| 1239 | ARR_HASNULL(arr) || |
| 1240 | ARR_ELEMTYPE(arr) != OIDOID) |
| 1241 | elog(ERROR, "conppeqop is not a 1-D Oid array" ); |
| 1242 | memcpy(pp_eq_oprs, ARR_DATA_PTR(arr), numkeys * sizeof(Oid)); |
| 1243 | if ((Pointer) arr != DatumGetPointer(adatum)) |
| 1244 | pfree(arr); /* free de-toasted copy, if any */ |
| 1245 | } |
| 1246 | |
| 1247 | if (ff_eq_oprs) |
| 1248 | { |
| 1249 | adatum = SysCacheGetAttr(CONSTROID, tuple, |
| 1250 | Anum_pg_constraint_conffeqop, &isNull); |
| 1251 | if (isNull) |
| 1252 | elog(ERROR, "null conffeqop for constraint %u" , constrId); |
| 1253 | arr = DatumGetArrayTypeP(adatum); /* ensure not toasted */ |
| 1254 | if (ARR_NDIM(arr) != 1 || |
| 1255 | ARR_DIMS(arr)[0] != numkeys || |
| 1256 | ARR_HASNULL(arr) || |
| 1257 | ARR_ELEMTYPE(arr) != OIDOID) |
| 1258 | elog(ERROR, "conffeqop is not a 1-D Oid array" ); |
| 1259 | memcpy(ff_eq_oprs, ARR_DATA_PTR(arr), numkeys * sizeof(Oid)); |
| 1260 | if ((Pointer) arr != DatumGetPointer(adatum)) |
| 1261 | pfree(arr); /* free de-toasted copy, if any */ |
| 1262 | } |
| 1263 | |
| 1264 | *numfks = numkeys; |
| 1265 | } |
| 1266 | |
| 1267 | /* |
| 1268 | * Determine whether a relation can be proven functionally dependent on |
| 1269 | * a set of grouping columns. If so, return true and add the pg_constraint |
| 1270 | * OIDs of the constraints needed for the proof to the *constraintDeps list. |
| 1271 | * |
| 1272 | * grouping_columns is a list of grouping expressions, in which columns of |
| 1273 | * the rel of interest are Vars with the indicated varno/varlevelsup. |
| 1274 | * |
| 1275 | * Currently we only check to see if the rel has a primary key that is a |
| 1276 | * subset of the grouping_columns. We could also use plain unique constraints |
| 1277 | * if all their columns are known not null, but there's a problem: we need |
| 1278 | * to be able to represent the not-null-ness as part of the constraints added |
| 1279 | * to *constraintDeps. FIXME whenever not-null constraints get represented |
| 1280 | * in pg_constraint. |
| 1281 | */ |
| 1282 | bool |
| 1283 | check_functional_grouping(Oid relid, |
| 1284 | Index varno, Index varlevelsup, |
| 1285 | List *grouping_columns, |
| 1286 | List **constraintDeps) |
| 1287 | { |
| 1288 | Bitmapset *pkattnos; |
| 1289 | Bitmapset *groupbyattnos; |
| 1290 | Oid constraintOid; |
| 1291 | ListCell *gl; |
| 1292 | |
| 1293 | /* If the rel has no PK, then we can't prove functional dependency */ |
| 1294 | pkattnos = get_primary_key_attnos(relid, false, &constraintOid); |
| 1295 | if (pkattnos == NULL) |
| 1296 | return false; |
| 1297 | |
| 1298 | /* Identify all the rel's columns that appear in grouping_columns */ |
| 1299 | groupbyattnos = NULL; |
| 1300 | foreach(gl, grouping_columns) |
| 1301 | { |
| 1302 | Var *gvar = (Var *) lfirst(gl); |
| 1303 | |
| 1304 | if (IsA(gvar, Var) && |
| 1305 | gvar->varno == varno && |
| 1306 | gvar->varlevelsup == varlevelsup) |
| 1307 | groupbyattnos = bms_add_member(groupbyattnos, |
| 1308 | gvar->varattno - FirstLowInvalidHeapAttributeNumber); |
| 1309 | } |
| 1310 | |
| 1311 | if (bms_is_subset(pkattnos, groupbyattnos)) |
| 1312 | { |
| 1313 | /* The PK is a subset of grouping_columns, so we win */ |
| 1314 | *constraintDeps = lappend_oid(*constraintDeps, constraintOid); |
| 1315 | return true; |
| 1316 | } |
| 1317 | |
| 1318 | return false; |
| 1319 | } |
| 1320 | |