| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.iapi.sql.dictionary.CheckConstraintDescriptor |
| 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 | import org.apache.derby.catalog.ReferencedColumns; |
| 23 | import org.apache.derby.catalog.UUID; |
| 24 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 25 | import org.apache.derby.iapi.sql.StatementType; |
| 26 | |
| 27 | /** |
| 28 | * This class represents a check constraint descriptor. |
| 29 | * |
| 30 | * @author jamie |
| 31 | */ |
| 32 | public class CheckConstraintDescriptor extends ConstraintDescriptor |
| 33 | { |
| 34 | ReferencedColumns referencedColumns; |
| 35 | String constraintText; |
| 36 | |
| 37 | CheckConstraintDescriptor( |
| 38 | DataDictionary dataDictionary, |
| 39 | TableDescriptor table, |
| 40 | String constraintName, |
| 41 | boolean deferrable, |
| 42 | boolean initiallyDeferred, |
| 43 | UUID constraintId, |
| 44 | String constraintText, |
| 45 | ReferencedColumns referencedColumns, |
| 46 | SchemaDescriptor schemaDesc, |
| 47 | boolean isEnabled |
| 48 | ) |
| 49 | { |
| 50 | super(dataDictionary, table, constraintName, deferrable, |
| 51 | initiallyDeferred, (int []) null, |
| 52 | constraintId, schemaDesc, isEnabled); |
| 53 | this.constraintText = constraintText; |
| 54 | this.referencedColumns = referencedColumns; |
| 55 | } |
| 56 | |
| 57 | /** |
| 58 | * Does this constraint have a backing index? |
| 59 | * |
| 60 | * @return boolean Whether or not there is a backing index for this constraint. |
| 61 | */ |
| 62 | public boolean hasBackingIndex() |
| 63 | { |
| 64 | return false; |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Gets an identifier telling what type of descriptor it is |
| 69 | * (UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK). |
| 70 | * |
| 71 | * @return An identifier telling what type of descriptor it is |
| 72 | * (UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK). |
| 73 | */ |
| 74 | public int getConstraintType() |
| 75 | { |
| 76 | return DataDictionary.CHECK_CONSTRAINT; |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * Get the text of the constraint. (Only non-null/meaningful for check |
| 81 | * constraints.) |
| 82 | * @return The constraint text. |
| 83 | */ |
| 84 | public String getConstraintText() |
| 85 | { |
| 86 | return constraintText; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * Get the UUID of the backing index, if one exists. |
| 91 | * |
| 92 | * @return The UUID of the backing index, if one exists, else null. |
| 93 | */ |
| 94 | public UUID getConglomerateId() |
| 95 | { |
| 96 | return null; |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * Get the ReferencedColumns. |
| 101 | * |
| 102 | * @return The ReferencedColumns. |
| 103 | */ |
| 104 | public ReferencedColumns getReferencedColumnsDescriptor() |
| 105 | { |
| 106 | return referencedColumns; |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Set the ReferencedColumns; used in drop column |
| 111 | * |
| 112 | * @param rcd The new ReferencedColumns. |
| 113 | */ |
| 114 | public void setReferencedColumnsDescriptor(ReferencedColumns rcd) |
| 115 | { |
| 116 | referencedColumns = rcd; |
| 117 | } |
| 118 | |
| 119 | /** |
| 120 | * Get the referenced columns as an int[] of column ids. |
| 121 | * |
| 122 | * @return The array of referenced column ids. |
| 123 | */ |
| 124 | public int[] getReferencedColumns() |
| 125 | { |
| 126 | return referencedColumns.getReferencedColumnPositions(); |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Does this constraint need to fire on this type of |
| 131 | * DML? For a check constraint, all inserts, and |
| 132 | * appropriate updates |
| 133 | * |
| 134 | * @param stmtType the type of DML |
| 135 | * (StatementType.INSERT|StatementType.UPDATE|StatementType.DELETE) |
| 136 | * @param modifiedCols the columns modified, or null for all |
| 137 | * |
| 138 | * @return true/false |
| 139 | */ |
| 140 | public boolean needsToFire(int stmtType, int[] modifiedCols) |
| 141 | { |
| 142 | /* |
| 143 | ** If we are disabled, we never fire |
| 144 | */ |
| 145 | if (!isEnabled) |
| 146 | { |
| 147 | return false; |
| 148 | } |
| 149 | |
| 150 | if (stmtType == StatementType.INSERT) |
| 151 | { |
| 152 | return true; |
| 153 | } |
| 154 | |
| 155 | if (stmtType == StatementType.DELETE) |
| 156 | { |
| 157 | return false; |
| 158 | } |
| 159 | |
| 160 | // if update, only relevant if columns intersect |
| 161 | return doColumnsIntersect(modifiedCols, getReferencedColumns()); |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * Convert the CheckConstraintDescriptor to a String. |
| 166 | * |
| 167 | * @return A String representation of this CheckConstraintDescriptor |
| 168 | */ |
| 169 | |
| 170 | public String toString() |
| 171 | { |
| 172 | if (SanityManager.DEBUG) |
| 173 | { |
| 174 | return "constraintText: " + constraintText + "\n" + |
| 175 | "referencedColumns: " + referencedColumns + "\n" + |
| 176 | super.toString(); |
| 177 | } |
| 178 | else |
| 179 | { |
| 180 | return ""; |
| 181 | } |
| 182 | } |
| 183 | |
| 184 | |
| 185 | } |