| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.sql.dictionary.DDUtils |
| 4 | |
| 5 | Copyright 2000, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.iapi.sql.dictionary; |
| 22 | |
| 23 | import org.apache.derby.iapi.error.StandardException; |
| 24 | |
| 25 | import org.apache.derby.iapi.reference.SQLState; |
| 26 | import org.apache.derby.iapi.sql.StatementType; |
| 27 | import java.util.Hashtable; |
| 28 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 29 | import org.apache.derby.iapi.services.i18n.MessageService; |
| 30 | import java.util.Enumeration; |
| 31 | |
| 32 | /** |
| 33 | * Static Data dictionary utilities. |
| 34 | * |
| 35 | * @version 0.1 |
| 36 | * @author Rick Hillegas |
| 37 | */ |
| 38 | |
| 39 | public class DDUtils |
| 40 | { |
| 41 | |
| 42 | /* |
| 43 | ** For a foreign key, this is used to locate the referenced |
| 44 | ** key using the ConstraintInfo. If it doesn't find the |
| 45 | ** correct constraint it will throw an error. |
| 46 | */ |
| 47 | public static ReferencedKeyConstraintDescriptor locateReferencedConstraint |
| 48 | ( |
| 49 | DataDictionary dd, |
| 50 | TableDescriptor td, |
| 51 | String myConstraintName, // for error messages |
| 52 | String[] myColumnNames, |
| 53 | ConsInfo otherConstraintInfo |
| 54 | ) |
| 55 | throws StandardException |
| 56 | { |
| 57 | TableDescriptor refTd = otherConstraintInfo.getReferencedTableDescriptor(dd); |
| 58 | if (refTd == null) |
| 59 | { |
| 60 | throw StandardException.newException(SQLState.LANG_INVALID_FK_NO_REF_TAB, |
| 61 | myConstraintName, |
| 62 | otherConstraintInfo.getReferencedTableName()); |
| 63 | } |
| 64 | |
| 65 | |
| 66 | ReferencedKeyConstraintDescriptor refCd = null; |
| 67 | |
| 68 | /* |
| 69 | ** There were no column names specified, just find |
| 70 | ** the primary key on the table in question |
| 71 | */ |
| 72 | String[] refColumnNames = otherConstraintInfo.getReferencedColumnNames(); |
| 73 | if (refColumnNames == null || |
| 74 | refColumnNames.length == 0) |
| 75 | { |
| 76 | refCd = refTd.getPrimaryKey(); |
| 77 | if (refCd == null) |
| 78 | { |
| 79 | throw StandardException.newException(SQLState.LANG_INVALID_FK_NO_PK, |
| 80 | myConstraintName, |
| 81 | refTd.getQualifiedName()); |
| 82 | } |
| 83 | |
| 84 | ColumnDescriptorList cdl = getColumnDescriptors(dd, td, myColumnNames); |
| 85 | |
| 86 | /* |
| 87 | ** Check the column list length to give a more informative |
| 88 | ** error in case they aren't the same. |
| 89 | */ |
| 90 | if (cdl.size() != refCd.getColumnDescriptors().size()) |
| 91 | { |
| 92 | throw StandardException.newException(SQLState.LANG_INVALID_FK_DIFFERENT_COL_COUNT, |
| 93 | myConstraintName, String.valueOf(cdl.size()), |
| 94 | String.valueOf(refCd.getColumnDescriptors().size())); |
| 95 | } |
| 96 | |
| 97 | /* |
| 98 | ** Make sure all types are the same. |
| 99 | */ |
| 100 | if (!refCd.areColumnsComparable(cdl)) |
| 101 | { |
| 102 | throw StandardException.newException(SQLState.LANG_INVALID_FK_COL_TYPES_DO_NOT_MATCH, |
| 103 | myConstraintName); |
| 104 | } |
| 105 | |
| 106 | return refCd; |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | ** Check the referenced columns vs. each unique or primary key to |
| 111 | ** see if they match the foreign key. |
| 112 | */ |
| 113 | else |
| 114 | { |
| 115 | ConstraintDescriptor cd; |
| 116 | |
| 117 | ColumnDescriptorList colDl = getColumnDescriptors(dd, td, myColumnNames); |
| 118 | ConstraintDescriptorList refCDL = dd.getConstraintDescriptors(refTd); |
| 119 | |
| 120 | int refCDLSize = refCDL.size(); |
| 121 | for (int index = 0; index < refCDLSize; index++) |
| 122 | { |
| 123 | cd = refCDL.elementAt(index); |
| 124 | |
| 125 | /* |
| 126 | ** Matches if it is not a check or fk, and |
| 127 | ** all the types line up. |
| 128 | */ |
| 129 | if ((cd instanceof ReferencedKeyConstraintDescriptor) && |
| 130 | cd.areColumnsComparable(colDl) && |
| 131 | columnNamesMatch(refColumnNames, |
| 132 | cd.getColumnDescriptors())) |
| 133 | { |
| 134 | return (ReferencedKeyConstraintDescriptor)cd; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | /* |
| 139 | ** If we got here, we didn't find anything |
| 140 | */ |
| 141 | throw StandardException.newException(SQLState.LANG_INVALID_FK_NO_REF_KEY, myConstraintName, |
| 142 | refTd.getQualifiedName()); |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | public static ColumnDescriptorList getColumnDescriptors |
| 147 | ( |
| 148 | DataDictionary dd, |
| 149 | TableDescriptor td, |
| 150 | String[] columnNames |
| 151 | ) |
| 152 | throws StandardException |
| 153 | { |
| 154 | ColumnDescriptorList cdl = new ColumnDescriptorList(); |
| 155 | for (int colCtr = 0; colCtr < columnNames.length; colCtr++) |
| 156 | { |
| 157 | ColumnDescriptor cd = td.getColumnDescriptor(columnNames[colCtr]); |
| 158 | cdl.add(td.getUUID(), cd); |
| 159 | } |
| 160 | return cdl; |
| 161 | } |
| 162 | |
| 163 | public static boolean columnNamesMatch(String []columnNames, ColumnDescriptorList cdl) |
| 164 | throws StandardException |
| 165 | { |
| 166 | if (columnNames.length != cdl.size()) |
| 167 | { |
| 168 | return false; |
| 169 | } |
| 170 | |
| 171 | String name; |
| 172 | for (int index = 0; index < columnNames.length; index++) |
| 173 | { |
| 174 | name = ((ColumnDescriptor) cdl.elementAt(index)).getColumnName(); |
| 175 | if (!name.equals(columnNames[index])) |
| 176 | { |
| 177 | return false; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | return true; |
| 182 | } |
| 183 | |
| 184 | |
| 185 | /* |
| 186 | **checks whether the foreign key relation ships referential action |
| 187 | **is violating the restrictions we have in the current system. |
| 188 | **/ |
| 189 | public static void validateReferentialActions |
| 190 | ( |
| 191 | DataDictionary dd, |
| 192 | TableDescriptor td, |
| 193 | String myConstraintName, // for error messages |
| 194 | ConsInfo otherConstraintInfo, |
| 195 | String[] columnNames |
| 196 | ) |
| 197 | throws StandardException |
| 198 | { |
| 199 | |
| 200 | |
| 201 | int refAction = otherConstraintInfo.getReferentialActionDeleteRule(); |
| 202 | |
| 203 | //Do not allow ON DELETE SET NULL as a referential action |
| 204 | //if none of the foreign key columns are nullable. |
| 205 | if(refAction == StatementType.RA_SETNULL) |
| 206 | { |
| 207 | boolean foundNullableColumn = false; |
| 208 | //check if we have a nullable foreign key column |
| 209 | for (int colCtr = 0; colCtr < columnNames.length; colCtr++) |
| 210 | { |
| 211 | ColumnDescriptor cd = td.getColumnDescriptor(columnNames[colCtr]); |
| 212 | if ((cd.getType().isNullable())) |
| 213 | { |
| 214 | foundNullableColumn = true; |
| 215 | break; |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | if(!foundNullableColumn) |
| 220 | { |
| 221 | throw StandardException.newException(SQLState.LANG_INVALID_FK_COL_FOR_SETNULL, |
| 222 | myConstraintName); |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | //check whether the foreign key relation ships referential action |
| 227 | //is not violating the restrictions we have in the current system. |
| 228 | TableDescriptor refTd = otherConstraintInfo.getReferencedTableDescriptor(dd); |
| 229 | Hashtable deleteConnHashtable = new Hashtable(); |
| 230 | //find whether the foreign key is self referencing. |
| 231 | boolean isSelfReferencingFk = (refTd.getUUID().equals(td.getUUID())); |
| 232 | String refTableName = refTd.getSchemaName() + "." + refTd.getName(); |
| 233 | //look for the other foreign key constraints on this table first |
| 234 | int currentSelfRefValue = getCurrentDeleteConnections(dd, td, -1, deleteConnHashtable, false, true); |
| 235 | validateDeleteConnection(dd, td, refTd, |
| 236 | refAction, |
| 237 | deleteConnHashtable, (Hashtable) deleteConnHashtable.clone(), |
| 238 | true, myConstraintName, false , |
| 239 | new StringBuffer(0), refTableName, |
| 240 | isSelfReferencingFk, |
| 241 | currentSelfRefValue); |
| 242 | |
| 243 | //if it not a selfreferencing key check for violation of exiting connections. |
| 244 | if(!isSelfReferencingFk) |
| 245 | { |
| 246 | checkForAnyExistingDeleteConnectionViolations(dd, td, |
| 247 | refAction, |
| 248 | deleteConnHashtable, |
| 249 | myConstraintName); |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | /* |
| 254 | ** Finds the existing delete connection for the table and the referential |
| 255 | ** actions that will occur and stores the information in the hash table. |
| 256 | ** HashTable (key , value) = ( table name that this table is delete |
| 257 | ** connected to, referential action that will occur if there is a delete on |
| 258 | ** the table this table connected to[CASACDE, SETNULL , RESTRICT ...etc).) |
| 259 | **/ |
| 260 | |
| 261 | private static int getCurrentDeleteConnections |
| 262 | ( |
| 263 | DataDictionary dd, |
| 264 | TableDescriptor td, |
| 265 | int refActionType, |
| 266 | Hashtable dch, |
| 267 | boolean prevNotCascade, |
| 268 | boolean findSelfRef |
| 269 | ) |
| 270 | throws StandardException |
| 271 | { |
| 272 | |
| 273 | int selfRefValue = -1; //store the self reference referential action |
| 274 | |
| 275 | //make sure we get any foreign key constraints added earlier in the same statement. |
| 276 | td.emptyConstraintDescriptorList(); |
| 277 | ConstraintDescriptorList cdl = dd.getConstraintDescriptors(td); |
| 278 | int cdlSize = cdl.size(); |
| 279 | |
| 280 | boolean passedInPrevNotCascade = prevNotCascade; |
| 281 | for (int index = 0; index < cdlSize; index++) |
| 282 | { |
| 283 | ConstraintDescriptor cd = cdl.elementAt(index); |
| 284 | |
| 285 | //look for foreign keys |
| 286 | if ((cd instanceof ForeignKeyConstraintDescriptor)) |
| 287 | { |
| 288 | ForeignKeyConstraintDescriptor fkcd = (ForeignKeyConstraintDescriptor) cd; |
| 289 | String constraintName = fkcd.getConstraintName(); |
| 290 | int raDeleteRule = fkcd.getRaDeleteRule(); |
| 291 | int raUpdateRule = fkcd.getRaUpdateRule(); |
| 292 | |
| 293 | if(findSelfRef && fkcd.isSelfReferencingFK()) |
| 294 | { |
| 295 | //All self references will have same referential actions type |
| 296 | selfRefValue = raDeleteRule; |
| 297 | findSelfRef = false; |
| 298 | } |
| 299 | |
| 300 | ReferencedKeyConstraintDescriptor refcd = |
| 301 | fkcd.getReferencedConstraint(); |
| 302 | TableDescriptor refTd = refcd.getTableDescriptor(); |
| 303 | int childRefAction = refActionType == -1 ? raDeleteRule : refActionType; |
| 304 | |
| 305 | String refTableName = refTd.getSchemaName() + "." + refTd.getName(); |
| 306 | //check with the existing references. |
| 307 | Integer rAction = ((Integer)dch.get(refTableName)); |
| 308 | if(rAction != null) // we already looked at this table |
| 309 | { |
| 310 | prevNotCascade = passedInPrevNotCascade; |
| 311 | continue; |
| 312 | } |
| 313 | |
| 314 | //if we are not cascading, check whether the link before |
| 315 | //this was cascade or not. If we travel through two NON CASCADE ACTION |
| 316 | //links then the delete connection is broken(only a delete can have further |
| 317 | // referential effects) |
| 318 | if(raDeleteRule != StatementType.RA_CASCADE) |
| 319 | { |
| 320 | if(prevNotCascade) |
| 321 | { |
| 322 | prevNotCascade = passedInPrevNotCascade; |
| 323 | continue; |
| 324 | } |
| 325 | else |
| 326 | prevNotCascade = true; |
| 327 | } |
| 328 | |
| 329 | //store the delete connection info in the hash table, |
| 330 | //note that the referential action value is not what is |
| 331 | //not specified on the current link. It is actually the |
| 332 | //value of what happens to the table whose delete |
| 333 | // connections we are finding. |
| 334 | dch.put(refTableName, (new Integer(childRefAction))); |
| 335 | |
| 336 | //find the next delete conectiions on this path for non |
| 337 | //self referencig delete connections. |
| 338 | if(!fkcd.isSelfReferencingFK()) |
| 339 | getCurrentDeleteConnections(dd , refTd, childRefAction, |
| 340 | dch, true, false); |
| 341 | prevNotCascade = passedInPrevNotCascade; |
| 342 | } |
| 343 | } |
| 344 | |
| 345 | return selfRefValue; |
| 346 | } |
| 347 | |
| 348 | |
| 349 | /* |
| 350 | ** Following function validates whether the new foreign key relation ship |
| 351 | ** violates any restriction on the referential actions. Current refAction |
| 352 | ** implementation does not allow cases where we can possible land up |
| 353 | ** having multiple action for the same row in a table, this happens becase |
| 354 | ** user can possibly define differential action through multiple paths. |
| 355 | ** Following function throws error while creating foreign keys if the new |
| 356 | ** releations ship leads to any such conditions. |
| 357 | ** NOTE : SQL99 standard also does not cleary says what we are suppose to do |
| 358 | ** in these non determenistic cases. |
| 359 | ** Our implementation just follows what is did in DB2 and throws error |
| 360 | ** messaged similar to DB2 (sql0632N, sql0633N, sql0634N) |
| 361 | */ |
| 362 | |
| 363 | private static void validateDeleteConnection |
| 364 | ( |
| 365 | DataDictionary dd, |
| 366 | TableDescriptor actualTd, // the table we are adding the foriegn key. |
| 367 | TableDescriptor refTd, |
| 368 | int refActionType, |
| 369 | Hashtable dch, |
| 370 | Hashtable ech, //existing delete connections |
| 371 | boolean checkImmediateRefTable, |
| 372 | String myConstraintName, |
| 373 | boolean prevNotCascade, |
| 374 | StringBuffer cycleString, |
| 375 | String currentRefTableName, //the name of the table we are referring too. |
| 376 | boolean isSelfReferencingFk, |
| 377 | int currentSelfRefValue |
| 378 | ) |
| 379 | throws StandardException |
| 380 | { |
| 381 | |
| 382 | Integer rAction; |
| 383 | |
| 384 | String refTableName = refTd.getSchemaName() + "." + refTd.getName(); |
| 385 | |
| 386 | |
| 387 | /* |
| 388 | ** Validate the new referentail action value with respect to the |
| 389 | ** already existing connections to this table we gathered from |
| 390 | ** the getCurrentDeleteConnections() call. |
| 391 | */ |
| 392 | |
| 393 | if(checkImmediateRefTable) |
| 394 | { |
| 395 | rAction = ((Integer)dch.get(refTableName)); |
| 396 | |
| 397 | // check possible invalide cases incase of self referencing foreign key |
| 398 | if(isSelfReferencingFk) |
| 399 | { |
| 400 | //All the relation ship referring to a table should have the |
| 401 | //same refaction except incase of SET NULL. In this case |
| 402 | //it is the same table , so we have to check with existing self |
| 403 | //referencing actions. |
| 404 | if(currentSelfRefValue != -1) |
| 405 | { |
| 406 | if(currentSelfRefValue != refActionType) |
| 407 | { |
| 408 | //If there is a SET NULL relation ship we can not have any |
| 409 | // other relation ship with it. |
| 410 | if(currentSelfRefValue == StatementType.RA_SETNULL) |
| 411 | throw |
| 412 | generateError(SQLState.LANG_CANT_BE_DEPENDENT_ESELF, |
| 413 | myConstraintName, currentRefTableName); |
| 414 | else |
| 415 | { |
| 416 | /* |
| 417 | ** case where we can cleary say what the |
| 418 | ** referential actions should be. Like, |
| 419 | ** if there is NO ACTION relationsip |
| 420 | **already, new relation ship also shold be NO ACTION. |
| 421 | */ |
| 422 | throw |
| 423 | generateError(SQLState.LANG_DELETE_RULE_MUSTBE_ESELF, |
| 424 | myConstraintName, currentSelfRefValue); |
| 425 | } |
| 426 | }else |
| 427 | { |
| 428 | //more than one ON DELET SET NULL to the same table is not allowed |
| 429 | if(currentSelfRefValue == StatementType.RA_SETNULL && |
| 430 | refActionType == StatementType.RA_SETNULL) |
| 431 | { |
| 432 | throw |
| 433 | generateError(SQLState.LANG_CANT_BE_DEPENDENT_ESELF, |
| 434 | myConstraintName, currentRefTableName); |
| 435 | } |
| 436 | } |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | ** If the new releation ship is self referencing and if |
| 441 | ** the current existing relation ship to other tables is |
| 442 | ** CASCADE type them new self reference should be of type |
| 443 | ** CASCADE, otherwise we should throw error. |
| 444 | */ |
| 445 | |
| 446 | if(isSelfReferencingFk && dch.contains(new Integer(StatementType.RA_CASCADE)) && |
| 447 | refActionType!= StatementType.RA_CASCADE) |
| 448 | { |
| 449 | throw |
| 450 | generateError(SQLState.LANG_DELETE_RULE_MUSTBE_ECASCADE, |
| 451 | myConstraintName,StatementType.RA_CASCADE); |
| 452 | } |
| 453 | |
| 454 | //end of possible error case scenarios for self reference key additions |
| 455 | return; |
| 456 | } |
| 457 | |
| 458 | //cases where the new reference is referring to another table |
| 459 | |
| 460 | //check whether it matched with existing self references. |
| 461 | // If A self-referencing constraint exists with a delete rule of |
| 462 | // SET NULL, NO ACTION or RESTRICT. We can not add CASCADE |
| 463 | // relationship with another table. |
| 464 | |
| 465 | if(currentSelfRefValue != -1) |
| 466 | { |
| 467 | if(refActionType == StatementType.RA_CASCADE && |
| 468 | currentSelfRefValue != StatementType.RA_CASCADE) |
| 469 | { |
| 470 | throw generateError(SQLState.LANG_DELETE_RULE_CANT_BE_CASCADE_ESELF, myConstraintName); |
| 471 | |
| 472 | } |
| 473 | |
| 474 | } |
| 475 | |
| 476 | |
| 477 | //check for the cases with existing relationships to the |
| 478 | //referenced table |
| 479 | if(rAction != null) |
| 480 | { |
| 481 | checkForMultiplePathInvalidCases(rAction.intValue(), |
| 482 | refActionType, |
| 483 | myConstraintName,currentRefTableName); |
| 484 | } |
| 485 | |
| 486 | |
| 487 | //mark the current connect to the reference table to identify the cycle. |
| 488 | if(refActionType != StatementType.RA_CASCADE) |
| 489 | { |
| 490 | prevNotCascade = true; |
| 491 | } |
| 492 | |
| 493 | /* |
| 494 | ** cycle string is used to keep track of the referential actions of |
| 495 | ** the nodes we visited, this is required to make sure that in case |
| 496 | ** of cycles , all the nodes in the cycle have same type of |
| 497 | ** referential action. |
| 498 | **/ |
| 499 | cycleString = cycleString.append(refActionType); |
| 500 | } |
| 501 | |
| 502 | |
| 503 | boolean passedInPrevNotCascade = prevNotCascade; |
| 504 | |
| 505 | //delete connection is broken for if we see ON DELET SET NULL link |
| 506 | // one level deeper than the table we are adding the foreing key |
| 507 | //Where as to check for cycles we need to go for more level also; |
| 508 | // To check cases like CASCADE CASCADE SET NULL cycle is not valid. |
| 509 | //Following variable is used make the distinction. |
| 510 | boolean multiPathCheck = true; |
| 511 | |
| 512 | // check for cases where the new connection we are forming to the |
| 513 | // reference table could create invalid any cycles or mutiple paths |
| 514 | // with the delete-connections the referencing table might have already. |
| 515 | ConstraintDescriptorList refCDL = dd.getConstraintDescriptors(refTd); |
| 516 | int refCDLSize = refCDL.size(); |
| 517 | for (int index = 0; index < refCDLSize; index++) |
| 518 | { |
| 519 | ConstraintDescriptor cd = refCDL.elementAt(index); |
| 520 | |
| 521 | if ((cd instanceof ForeignKeyConstraintDescriptor)) |
| 522 | { |
| 523 | ForeignKeyConstraintDescriptor fkcd = (ForeignKeyConstraintDescriptor) cd; |
| 524 | String constraintName = fkcd.getConstraintName(); |
| 525 | int raDeleteRule = fkcd.getRaDeleteRule(); |
| 526 | int raUpdateRule = fkcd.getRaUpdateRule(); |
| 527 | |
| 528 | ReferencedKeyConstraintDescriptor refcd = |
| 529 | fkcd.getReferencedConstraint(); |
| 530 | TableDescriptor nextRefTd = refcd.getTableDescriptor(); |
| 531 | |
| 532 | //if we are not cascading, check whether the link before |
| 533 | //this was cascade or not. If we travel through two NON CASCADE ACTION |
| 534 | //links then the delete connection is broken(only a delete can have further |
| 535 | //referential effects) |
| 536 | if(raDeleteRule != StatementType.RA_CASCADE) |
| 537 | { |
| 538 | if(prevNotCascade) |
| 539 | { |
| 540 | prevNotCascade = passedInPrevNotCascade; |
| 541 | continue; |
| 542 | } |
| 543 | else |
| 544 | { |
| 545 | prevNotCascade = true; |
| 546 | multiPathCheck = false; |
| 547 | } |
| 548 | |
| 549 | } |
| 550 | |
| 551 | //check whether the current link is a self referencing one |
| 552 | boolean isSelfRefLink = fkcd.isSelfReferencingFK(); |
| 553 | |
| 554 | //check for this is non self referencing cycles case |
| 555 | //In cases of cycle, whole cycle should have the same refAction |
| 556 | // value. Other wise we should throw an exception |
| 557 | cycleString = cycleString.append(raDeleteRule); |
| 558 | boolean isFormingCycle = (nextRefTd.getUUID().equals(actualTd.getUUID())); |
| 559 | if(isFormingCycle) |
| 560 | { |
| 561 | //make sure that all the nodes in the cycle have the same |
| 562 | //referential action value, otherwise we should throw an error. |
| 563 | for(int i = 0 ; i < cycleString.length(); i++) |
| 564 | { |
| 565 | int otherRefAction = Character.getNumericValue(cycleString.charAt(i)); |
| 566 | if(otherRefAction != refActionType) |
| 567 | { |
| 568 | //cases where one of the existing relation ships in |
| 569 | //the cycle is not cascade , so we can not have |
| 570 | // cascade relation ship. |
| 571 | if(otherRefAction != StatementType.RA_CASCADE) |
| 572 | { |
| 573 | throw generateError(SQLState.LANG_DELETE_RULE_CANT_BE_CASCADE_ECYCLE, myConstraintName); |
| 574 | } |
| 575 | else |
| 576 | { |
| 577 | //possibly all the other nodes in the cycle has |
| 578 | //cascade relationsship , we can not add a non |
| 579 | //cascade relation ship. |
| 580 | throw |
| 581 | generateError(SQLState.LANG_CANT_BE_DEPENDENT_ECYCLE, |
| 582 | myConstraintName, currentRefTableName); |
| 583 | } |
| 584 | } |
| 585 | } |
| 586 | } |
| 587 | |
| 588 | |
| 589 | |
| 590 | |
| 591 | String nextRefTableName = nextRefTd.getSchemaName() + "." + nextRefTd.getName(); |
| 592 | rAction = ((Integer)ech.get(nextRefTableName)); |
| 593 | if(rAction != null) |
| 594 | { |
| 595 | /* |
| 596 | ** If the table name has entry in the hash table means, there |
| 597 | ** is already a path to this table exists from the table |
| 598 | ** the new foreign key relation ship is being formed. |
| 599 | ** Note: refValue in the hash table is how the table we are |
| 600 | ** adding the new relationsship is going to affected not |
| 601 | ** current path refvalue. |
| 602 | **/ |
| 603 | if(!isSelfRefLink && multiPathCheck) |
| 604 | checkForMultiplePathInvalidCases(rAction.intValue(), |
| 605 | refActionType, |
| 606 | myConstraintName,currentRefTableName); |
| 607 | |
| 608 | }else |
| 609 | { |
| 610 | rAction = ((Integer)dch.get(nextRefTableName)); |
| 611 | if(rAction == null) |
| 612 | { |
| 613 | if(multiPathCheck) |
| 614 | dch.put(nextRefTableName, (new Integer(refActionType))); |
| 615 | if(!isSelfRefLink) |
| 616 | { |
| 617 | validateDeleteConnection(dd, actualTd, nextRefTd, |
| 618 | refActionType, dch, ech, false, |
| 619 | myConstraintName,prevNotCascade, |
| 620 | cycleString, currentRefTableName, |
| 621 | isSelfReferencingFk, currentSelfRefValue); |
| 622 | } |
| 623 | } |
| 624 | } |
| 625 | prevNotCascade = passedInPrevNotCascade; |
| 626 | //removes the char added for the current call |
| 627 | cycleString.setLength(cycleString.length() -1); |
| 628 | |
| 629 | } |
| 630 | } |
| 631 | } |
| 632 | |
| 633 | |
| 634 | /* |
| 635 | **Check whether the mulitple path case is valid or not following |
| 636 | ** cases are invalid: |
| 637 | ** case 1: The relationship causes the table to be delete-connected to |
| 638 | ** the indicated table through multiple relationships and the |
| 639 | ** delete rule of the existing relationship is SET NULL. |
| 640 | ** case 2: The relationship would cause the table to be |
| 641 | ** delete-connected to the same table through multiple |
| 642 | ** relationships and such relationships must have the same |
| 643 | ** delete rule (NO ACTION, RESTRICT or CASCADE). |
| 644 | ** case 3: The relationship would cause another table to be |
| 645 | ** delete-connected to the same table through multiple paths |
| 646 | ** with different delete rules or with delete rule equal to SET NULL. |
| 647 | **/ |
| 648 | |
| 649 | private static void checkForMultiplePathInvalidCases(int currentRefAction, |
| 650 | int refActionType, |
| 651 | String myConstraintName, |
| 652 | String currentRefTableName) |
| 653 | throws StandardException |
| 654 | { |
| 655 | |
| 656 | //All the relation ship referring to a table should have the |
| 657 | //same refaction except incase of SET NULL |
| 658 | if(currentRefAction != refActionType) |
| 659 | { |
| 660 | |
| 661 | //If there is a SET NULL relation ship we can not have any |
| 662 | // other relation ship with it. |
| 663 | if(currentRefAction == StatementType.RA_SETNULL) |
| 664 | throw generateError(SQLState.LANG_CANT_BE_DEPENDENT_MPATH, |
| 665 | myConstraintName, currentRefTableName); |
| 666 | else |
| 667 | //This error say what the delete rule must be for the |
| 668 | // foreign key be valid |
| 669 | throw generateError(SQLState.LANG_DELETE_RULE_MUSTBE_MPATH, |
| 670 | myConstraintName, currentRefAction); |
| 671 | |
| 672 | }else |
| 673 | { |
| 674 | //more than one ON DELET SET NULL to the same table is not allowed |
| 675 | if(currentRefAction == StatementType.RA_SETNULL && |
| 676 | refActionType == StatementType.RA_SETNULL) |
| 677 | { |
| 678 | throw |
| 679 | generateError(SQLState.LANG_CANT_BE_DEPENDENT_MPATH, |
| 680 | myConstraintName, currentRefTableName); |
| 681 | } |
| 682 | } |
| 683 | } |
| 684 | |
| 685 | |
| 686 | |
| 687 | /* |
| 688 | ** Check whether the delete rule of FOREIGN KEY must not be CASCADE because |
| 689 | ** the new relationship would cause another table to be delete-connected to |
| 690 | ** the same table through multiple paths with different delete rules or with |
| 691 | ** delete rule equal to SET NULL. |
| 692 | ** |
| 693 | ** For example : |
| 694 | ** t1 |
| 695 | ** CASCADE / \ CASCADE |
| 696 | ** / \ |
| 697 | ** t2 t3 |
| 698 | ** \ / |
| 699 | ** SET NULL \ / CASCADE (Can we add this one ? NO) |
| 700 | ** \ / |
| 701 | \t4/ |
| 702 | ** |
| 703 | ** existing links: |
| 704 | ** t2 references t1 ON DELETE CASCADE (fkey1) |
| 705 | ** t3 references t1 ON DELETE CASCADE (fkey2) |
| 706 | ** t2 reference t4 ON DELETE SET NULL (fkey3) |
| 707 | ** Now if if try to add a new link i.e |
| 708 | ** t4 references t3 ON DELETE SET NULL (fkey4) |
| 709 | ** Say if we add it, then if we execute 'delete from t1' |
| 710 | ** Because of referential actions , we will try to delete a row through |
| 711 | ** one path and tries to update through another path. |
| 712 | ** Nothing in standard that say whether we are suppose to delete the row |
| 713 | ** or update the row. DB2UDB raises error when we try to create the |
| 714 | ** foreign key fkey4, cloudscape also does the same. |
| 715 | ** |
| 716 | ** How we catch the error case ? |
| 717 | ** Point to note here is the table(t4) we are adding the foreign key does |
| 718 | ** not have a problem in this scenarion because we are adding a |
| 719 | ** a CASACDE link , some other table(t2) that is referring |
| 720 | ** can get multiple referential action paths. We can not |
| 721 | ** this error case for self referencing links. |
| 722 | ** Algorithm: |
| 723 | ** -Gather the foreign keys that are |
| 724 | ** referring(ReferencedKeyConstraintDescriptor) to the table we are adding |
| 725 | ** foreign key, in our example case we get (fkey3 - table t2 -t4 link) |
| 726 | ** for each ReferencedKeyConstraintDescriptor |
| 727 | ** { |
| 728 | ** 1)find the delete connections of the referring table. |
| 729 | ** [getCurrentDeleteConnections() will return this hash table] |
| 730 | ** 2) we already have collected the Delete connections |
| 731 | ** in validDeleteConnections() for the actual table we are adding the |
| 732 | ** foreign key. |
| 733 | ** 3) Now check whether the referring table is also |
| 734 | ** referring any table that the table we are adding |
| 735 | ** foreign key has delete connection. |
| 736 | ** |
| 737 | ** for each table referring table delete connection hash table |
| 738 | ** { |
| 739 | ** if it is there in the actual table delete connection hash table |
| 740 | ** { |
| 741 | ** //In our example case we find t1 in both the hash tables. |
| 742 | ** make sure we are having valid referential action |
| 743 | ** from the existing path and the new path we got from |
| 744 | ** new foreign key relation ship. |
| 745 | ** //In our example case t2 has CASCADE relations with t1 |
| 746 | ** //Because of new foreign key added we also get |
| 747 | ** //SET NULL relation ship with t1. This is not valid |
| 748 | ** //so we should throw error. |
| 749 | ** } |
| 750 | ** } |
| 751 | ** } |
| 752 | **/ |
| 753 | |
| 754 | |
| 755 | private static void checkForAnyExistingDeleteConnectionViolations |
| 756 | ( |
| 757 | DataDictionary dd, |
| 758 | TableDescriptor td, |
| 759 | int refActionType, |
| 760 | Hashtable newDconnHashTable, |
| 761 | String myConstraintName |
| 762 | ) |
| 763 | throws StandardException |
| 764 | { |
| 765 | |
| 766 | //We need to check for the condition in this function only when we are |
| 767 | //adding ref action of type CASCADE |
| 768 | if(refActionType != StatementType.RA_CASCADE) |
| 769 | return; |
| 770 | |
| 771 | //find the tables that are referring to the table we |
| 772 | //are adding the foreign key and check whether we violate their existing rules. |
| 773 | String addTableName = td.getSchemaName() + "." + td.getName();; |
| 774 | ConstraintDescriptorList refCDL = dd.getConstraintDescriptors(td); |
| 775 | int refCDLSize = refCDL.size(); |
| 776 | for (int index = 0; index < refCDLSize; index++) |
| 777 | { |
| 778 | ConstraintDescriptor cd = refCDL.elementAt(index); |
| 779 | |
| 780 | if ((cd instanceof ReferencedKeyConstraintDescriptor)) |
| 781 | { |
| 782 | ConstraintDescriptorList fkcdl = dd.getActiveConstraintDescriptors |
| 783 | ( ((ReferencedKeyConstraintDescriptor)cd).getForeignKeyConstraints(ConstraintDescriptor.ALL)); |
| 784 | |
| 785 | int size = fkcdl.size(); |
| 786 | if (size == 0) |
| 787 | { |
| 788 | continue; |
| 789 | } |
| 790 | |
| 791 | //Note: More than one table can refer to the same |
| 792 | //ReferencedKeyConstraintDescriptor, so we need to find all the tables. |
| 793 | Hashtable dConnHashtable = new Hashtable(); |
| 794 | for (int inner = 0; inner < size; inner++) |
| 795 | { |
| 796 | ForeignKeyConstraintDescriptor fkcd = (ForeignKeyConstraintDescriptor) fkcdl.elementAt(inner); |
| 797 | TableDescriptor fktd = fkcd.getTableDescriptor(); |
| 798 | //Delete rule that we have to the table we are adding the |
| 799 | // foreign key relation shop |
| 800 | int raDeleteRuleToAddTable = fkcd.getRaDeleteRule(); |
| 801 | |
| 802 | //This check should not be done on self referencing references. |
| 803 | if(!fkcd.isSelfReferencingFK()) |
| 804 | { |
| 805 | |
| 806 | //gather the delete connections of the table that is |
| 807 | //referring to the table we are adding foreign key relation ship |
| 808 | |
| 809 | getCurrentDeleteConnections(dd, fktd, -1, dConnHashtable, false, true); |
| 810 | |
| 811 | /* |
| 812 | **Find out if we introduced more than one delete connection |
| 813 | **paths to the table that are referring the table we adding |
| 814 | **the foreign key relatiosn ship. |
| 815 | **If we have multiple paths they should have the same type |
| 816 | **referential action and only one SET NULL path. |
| 817 | **/ |
| 818 | |
| 819 | for (Enumeration e = dConnHashtable.keys() ; e.hasMoreElements() ;) |
| 820 | { |
| 821 | String tName = (String) e.nextElement(); |
| 822 | //we should not check for the table name to which we are |
| 823 | //adding the foreign key relation ship. |
| 824 | if(!tName.equals(addTableName)) |
| 825 | { |
| 826 | if(newDconnHashTable.containsKey(tName)) |
| 827 | { |
| 828 | int currentDeleteRule = ((Integer) dConnHashtable.get(tName)).intValue(); |
| 829 | if((currentDeleteRule == StatementType.RA_SETNULL |
| 830 | && raDeleteRuleToAddTable == StatementType.RA_SETNULL) || |
| 831 | currentDeleteRule != raDeleteRuleToAddTable) |
| 832 | { |
| 833 | throw |
| 834 | generateError(SQLState.LANG_DELETE_RULE_CANT_BE_CASCADE_MPATH, |
| 835 | myConstraintName); |
| 836 | } |
| 837 | } |
| 838 | } |
| 839 | } |
| 840 | } |
| 841 | //same hash table can be used for the other referring tables |
| 842 | //so clear the hash table. |
| 843 | dConnHashtable.clear(); |
| 844 | } |
| 845 | } |
| 846 | } |
| 847 | } |
| 848 | |
| 849 | |
| 850 | |
| 851 | private static StandardException generateError(String messageId, |
| 852 | String myConstraintName) |
| 853 | { |
| 854 | String message = MessageService.getTextMessage(messageId); |
| 855 | return StandardException.newException(SQLState.LANG_DELETE_RULE_VIOLATION, |
| 856 | myConstraintName, message); |
| 857 | } |
| 858 | |
| 859 | private static StandardException generateError(String messageId, |
| 860 | String myConstraintName, |
| 861 | int raRule) |
| 862 | { |
| 863 | String raRuleStringId; |
| 864 | switch (raRule){ |
| 865 | case StatementType.RA_CASCADE: |
| 866 | raRuleStringId = SQLState.LANG_DELETE_RULE_CASCADE; |
| 867 | break; |
| 868 | case StatementType.RA_RESTRICT: |
| 869 | raRuleStringId = SQLState.LANG_DELETE_RULE_RESTRICT; |
| 870 | break; |
| 871 | case StatementType.RA_NOACTION: |
| 872 | raRuleStringId = SQLState.LANG_DELETE_RULE_NOACTION; |
| 873 | break; |
| 874 | case StatementType.RA_SETNULL: |
| 875 | raRuleStringId = SQLState.LANG_DELETE_RULE_SETNULL; |
| 876 | break; |
| 877 | case StatementType.RA_SETDEFAULT: |
| 878 | raRuleStringId = SQLState.LANG_DELETE_RULE_SETDEFAULT; |
| 879 | break; |
| 880 | default: |
| 881 | raRuleStringId =SQLState.LANG_DELETE_RULE_NOACTION ; // NO ACTION (default value) |
| 882 | } |
| 883 | |
| 884 | String raRuleMessageString = MessageService.getTextMessage(raRuleStringId); |
| 885 | String message = MessageService.getTextMessage(messageId, raRuleMessageString); |
| 886 | return StandardException.newException(SQLState.LANG_DELETE_RULE_VIOLATION, |
| 887 | myConstraintName, message); |
| 888 | } |
| 889 | |
| 890 | private static StandardException generateError(String messageId, |
| 891 | String myConstraintName, |
| 892 | String refTableName) |
| 893 | { |
| 894 | |
| 895 | String message = MessageService.getTextMessage(messageId, refTableName); |
| 896 | return StandardException.newException(SQLState.LANG_DELETE_RULE_VIOLATION, |
| 897 | myConstraintName, message); |
| 898 | } |
| 899 | |
| 900 | } |
| 901 | |
| 902 | |
| 903 | |
| 904 | |
| 905 | |
| 906 | |
| 907 | |
| 908 | |
| 909 | |
| 910 | |
| 911 | |
| 912 | |
| 913 | |
| 914 | |
| 915 | |