| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.sql.dictionary.ReferencedKeyConstraintDescriptor |
| 4 | |
| 5 | Copyright 1998, 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.services.sanity.SanityManager; |
| 27 | import org.apache.derby.iapi.sql.StatementType; |
| 28 | import org.apache.derby.iapi.services.io.StoredFormatIds; |
| 29 | import org.apache.derby.catalog.UUID; |
| 30 | /** |
| 31 | * A ReferencedConstraintDeescriptor is a primary key or a unique |
| 32 | * key that is referenced by a foreign key. |
| 33 | * |
| 34 | * @author Jamie |
| 35 | */ |
| 36 | public class ReferencedKeyConstraintDescriptor extends KeyConstraintDescriptor |
| 37 | { |
| 38 | /** |
| 39 | public interface to this descriptor: |
| 40 | <ol> |
| 41 | <li>public boolean hasSelfReferencingFK(ConstraintDescriptorList cdl, int type) |
| 42 | throws StandardException;</li> |
| 43 | <li>public ConstraintDescriptorList getForeignKeyConstraints(int type) throws StandardException;</li> |
| 44 | <li>public boolean isReferenced();</li> |
| 45 | <li>public int getReferenceCount();</li> |
| 46 | <li>public int incrementReferenceCount();</li> |
| 47 | <li>public int decrementReferenceCount();</li> |
| 48 | </ol> |
| 49 | */ |
| 50 | |
| 51 | //Implementation |
| 52 | private final int constraintType; |
| 53 | |
| 54 | int referenceCount; |
| 55 | |
| 56 | // enabled foreign keys |
| 57 | private ConstraintDescriptorList fkEnabledConstraintList; |
| 58 | // all foreign keys |
| 59 | private ConstraintDescriptorList fkConstraintList; |
| 60 | |
| 61 | private boolean checkedSelfReferencing; |
| 62 | private boolean hasSelfReferencing; |
| 63 | |
| 64 | /** |
| 65 | * Constructor for a KeyConstraintDescriptorImpl |
| 66 | * |
| 67 | * @param constraintType The type of the constraint |
| 68 | * @param dataDictionary The data dictionary that this descriptor lives in |
| 69 | * @param table The descriptor of the table the constraint is on |
| 70 | * @param constraintName The name of the constraint. |
| 71 | * @param deferrable If the constraint can be deferred. |
| 72 | * @param initiallyDeferred If the constraint starts life deferred. |
| 73 | * @param columns columns involved in the constraint |
| 74 | * @param constraintId UUID of constraint |
| 75 | * @param indexId The UUID for the backing index |
| 76 | * @param schemaDesc The SchemaDescriptor for the constraint |
| 77 | * @param isEnabled is the constraint enabled? |
| 78 | * @param referenceCount number of FKs (enabled only) |
| 79 | */ |
| 80 | protected ReferencedKeyConstraintDescriptor(int constraintType, |
| 81 | DataDictionary dataDictionary, |
| 82 | TableDescriptor table, |
| 83 | String constraintName, |
| 84 | boolean deferrable, |
| 85 | boolean initiallyDeferred, |
| 86 | int[] columns, |
| 87 | UUID constraintId, |
| 88 | UUID indexId, |
| 89 | SchemaDescriptor schemaDesc, |
| 90 | boolean isEnabled, |
| 91 | int referenceCount |
| 92 | ) |
| 93 | { |
| 94 | super(dataDictionary, table, constraintName, deferrable, |
| 95 | initiallyDeferred, columns, |
| 96 | constraintId, indexId, schemaDesc, isEnabled); |
| 97 | this.referenceCount = referenceCount; |
| 98 | this.constraintType = constraintType; |
| 99 | } |
| 100 | |
| 101 | public final int getConstraintType() { |
| 102 | return constraintType; |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Am I referenced by a FK on the same table? |
| 107 | * |
| 108 | * @param cdl ConstraintDescriptorList for the table |
| 109 | * @param type ConstraintDescriptor.(ENABLED|DISABLED|ALL) |
| 110 | * |
| 111 | * @return true/false |
| 112 | * |
| 113 | * @exception StandardException on error |
| 114 | */ |
| 115 | public boolean hasSelfReferencingFK(ConstraintDescriptorList cdl, int type) |
| 116 | throws StandardException |
| 117 | { |
| 118 | if (SanityManager.DEBUG) |
| 119 | { |
| 120 | checkType(type); |
| 121 | } |
| 122 | |
| 123 | if (checkedSelfReferencing) |
| 124 | { |
| 125 | return hasSelfReferencing; |
| 126 | } |
| 127 | |
| 128 | ConstraintDescriptor cd; |
| 129 | ForeignKeyConstraintDescriptor fkcd; |
| 130 | /* Get a full list of referencing keys, if caller |
| 131 | * passed in null CDL. |
| 132 | */ |
| 133 | if (cdl == null) |
| 134 | { |
| 135 | cdl = getForeignKeyConstraints(type); |
| 136 | } |
| 137 | int cdlSize = cdl.size(); |
| 138 | |
| 139 | for (int index = 0; index < cdlSize; index++) |
| 140 | { |
| 141 | cd = (ConstraintDescriptor) cdl.elementAt(index); |
| 142 | if (! (cd instanceof ForeignKeyConstraintDescriptor)) |
| 143 | { |
| 144 | continue; |
| 145 | } |
| 146 | |
| 147 | fkcd = (ForeignKeyConstraintDescriptor) cd; |
| 148 | if (fkcd.getReferencedConstraintId().equals(getUUID())) |
| 149 | { |
| 150 | hasSelfReferencing = true; |
| 151 | break; |
| 152 | } |
| 153 | } |
| 154 | return hasSelfReferencing; |
| 155 | } |
| 156 | |
| 157 | |
| 158 | /** |
| 159 | * Am I referenced by a FK on another table? |
| 160 | * @param type ConstraintDescriptor.(ENABLED|DISABLED|ALL) |
| 161 | * @return true/false |
| 162 | * @exception StandardException on error |
| 163 | */ |
| 164 | public boolean hasNonSelfReferencingFK(int type) |
| 165 | throws StandardException |
| 166 | { |
| 167 | |
| 168 | boolean hasNonSelfReferenceFk = false; |
| 169 | |
| 170 | if (SanityManager.DEBUG) |
| 171 | { |
| 172 | checkType(type); |
| 173 | } |
| 174 | |
| 175 | ConstraintDescriptor cd; |
| 176 | ForeignKeyConstraintDescriptor fkcd; |
| 177 | // Get a full list of referencing keys, |
| 178 | ConstraintDescriptorList cdl = getForeignKeyConstraints(type); |
| 179 | int cdlSize = cdl.size(); |
| 180 | |
| 181 | for (int index = 0; index < cdlSize; index++) |
| 182 | { |
| 183 | cd = (ConstraintDescriptor) cdl.elementAt(index); |
| 184 | if (! (cd instanceof ForeignKeyConstraintDescriptor)) |
| 185 | { |
| 186 | continue; |
| 187 | } |
| 188 | |
| 189 | fkcd = (ForeignKeyConstraintDescriptor) cd; |
| 190 | if(!(fkcd.getTableId().equals(getTableId()))) |
| 191 | { |
| 192 | hasNonSelfReferenceFk = true; |
| 193 | break; |
| 194 | } |
| 195 | } |
| 196 | return hasNonSelfReferenceFk; |
| 197 | } |
| 198 | |
| 199 | |
| 200 | |
| 201 | /** |
| 202 | * Get the referencing foreign key constraints |
| 203 | * |
| 204 | * @param type ConstraintDescriptor.(ENABLED|DISABLED|ALL) |
| 205 | * |
| 206 | * @return the list of constraints (ConstraintDescriptorListImpl) |
| 207 | * |
| 208 | * @exception StandardException on error |
| 209 | */ |
| 210 | public ConstraintDescriptorList getForeignKeyConstraints(int type) |
| 211 | throws StandardException |
| 212 | { |
| 213 | if (SanityManager.DEBUG) |
| 214 | { |
| 215 | checkType(type); |
| 216 | } |
| 217 | |
| 218 | // optimized for this case |
| 219 | if (type == ENABLED) |
| 220 | { |
| 221 | // optimization to avoid any lookups if we know we |
| 222 | // aren't referenced. |
| 223 | if (!isReferenced()) |
| 224 | { |
| 225 | return new ConstraintDescriptorList(); |
| 226 | } |
| 227 | else if (fkEnabledConstraintList != null) |
| 228 | { |
| 229 | return fkEnabledConstraintList; |
| 230 | } |
| 231 | else if (fkConstraintList == null) |
| 232 | { |
| 233 | fkConstraintList = getDataDictionary().getForeignKeys(constraintId); |
| 234 | } |
| 235 | fkEnabledConstraintList = fkConstraintList.getConstraintDescriptorList(true); |
| 236 | return fkEnabledConstraintList; |
| 237 | } |
| 238 | |
| 239 | // not optimized for this case |
| 240 | else if (type == DISABLED) |
| 241 | { |
| 242 | if (fkConstraintList == null) |
| 243 | { |
| 244 | fkConstraintList = getDataDictionary().getForeignKeys(constraintId); |
| 245 | } |
| 246 | return fkConstraintList.getConstraintDescriptorList(false); |
| 247 | } |
| 248 | else |
| 249 | { |
| 250 | if (fkConstraintList == null) |
| 251 | { |
| 252 | fkConstraintList = getDataDictionary().getForeignKeys(constraintId); |
| 253 | } |
| 254 | return fkConstraintList; |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | /** |
| 259 | * Is this constraint referenced? Returns |
| 260 | * true if there are enabled fks that |
| 261 | * reference this constraint. |
| 262 | * |
| 263 | * @return false |
| 264 | */ |
| 265 | public boolean isReferenced() |
| 266 | { |
| 267 | return referenceCount != 0; |
| 268 | } |
| 269 | |
| 270 | /** |
| 271 | * Get the number of enabled fks that |
| 272 | * reference this key. |
| 273 | * |
| 274 | * @return the number of fks |
| 275 | */ |
| 276 | public int getReferenceCount() |
| 277 | { |
| 278 | return referenceCount; |
| 279 | } |
| 280 | |
| 281 | /** |
| 282 | * Bump the reference count by one. |
| 283 | * |
| 284 | * @return the number of fks |
| 285 | */ |
| 286 | public int incrementReferenceCount() |
| 287 | { |
| 288 | return referenceCount++; |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * Decrement the reference count by one. |
| 293 | * |
| 294 | * @return the number of fks |
| 295 | */ |
| 296 | public int decrementReferenceCount() |
| 297 | { |
| 298 | return referenceCount--; |
| 299 | } |
| 300 | |
| 301 | /** |
| 302 | * Does this constraint need to fire on this type of |
| 303 | * DML? For referenced keys, fire if referenced by |
| 304 | * a fk, and stmt is delete or bulk insert replace, |
| 305 | * or stmt is update and columns intersect. |
| 306 | * |
| 307 | * @param stmtType the type of DML |
| 308 | * (StatementType.INSERT|StatementType.UPDATE|StatementType.DELETE) |
| 309 | * @param modifiedCols the columns modified, or null for all |
| 310 | * |
| 311 | * @return true/false |
| 312 | */ |
| 313 | public boolean needsToFire(int stmtType, int[] modifiedCols) |
| 314 | { |
| 315 | /* |
| 316 | ** If we are disabled, we never fire |
| 317 | */ |
| 318 | if (!isEnabled) |
| 319 | { |
| 320 | return false; |
| 321 | } |
| 322 | |
| 323 | if (!isReferenced() || |
| 324 | (stmtType == StatementType.INSERT)) |
| 325 | { |
| 326 | return false; |
| 327 | } |
| 328 | |
| 329 | if (stmtType == StatementType.DELETE || |
| 330 | stmtType == StatementType.BULK_INSERT_REPLACE) |
| 331 | { |
| 332 | return true; |
| 333 | } |
| 334 | |
| 335 | // if update, only relevant if columns intersect |
| 336 | return doColumnsIntersect(modifiedCols, getReferencedColumns()); |
| 337 | } |
| 338 | |
| 339 | private void checkType(int type) throws StandardException |
| 340 | { |
| 341 | if (SanityManager.DEBUG) |
| 342 | { |
| 343 | switch (type) |
| 344 | { |
| 345 | case ENABLED: |
| 346 | case DISABLED: |
| 347 | case ALL: |
| 348 | break; |
| 349 | default: |
| 350 | SanityManager.THROWASSERT("constraint type "+type+" is invalid"); |
| 351 | } |
| 352 | } |
| 353 | } |
| 354 | |
| 355 | } |