--- /dev/null
+/*\r
+\r
+ Derby - Class org.apache.derby.iapi.sql.compile.OptimizablePredicate\r
+\r
+ Licensed to the Apache Software Foundation (ASF) under one or more\r
+ contributor license agreements. See the NOTICE file distributed with\r
+ this work for additional information regarding copyright ownership.\r
+ The ASF licenses this file to you under the Apache License, Version 2.0\r
+ (the "License"); you may not use this file except in compliance with\r
+ the License. You may obtain a copy of the License at\r
+\r
+ http://www.apache.org/licenses/LICENSE-2.0\r
+\r
+ Unless required by applicable law or agreed to in writing, software\r
+ distributed under the License is distributed on an "AS IS" BASIS,\r
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
+ See the License for the specific language governing permissions and\r
+ limitations under the License.\r
+\r
+ */\r
+\r
+package org.apache.derby.iapi.sql.compile;\r
+\r
+import org.apache.derby.iapi.error.StandardException;\r
+\r
+import org.apache.derby.iapi.types.DataValueDescriptor;\r
+\r
+import org.apache.derby.iapi.util.JBitSet;\r
+\r
+/**\r
+ * OptimizablePredicate provides services for optimizing predicates in a query.\r
+ */\r
+\r
+public interface OptimizablePredicate\r
+{\r
+ /**\r
+ * Get the map of referenced tables for this OptimizablePredicate.\r
+ *\r
+ * @return JBitSet Referenced table map.\r
+ */\r
+ JBitSet getReferencedMap();\r
+\r
+ /**\r
+ * Return whether or not an OptimizablePredicate contains a subquery.\r
+ *\r
+ * @return boolean Whether or not an OptimizablePredicate includes a subquery.\r
+ */\r
+ boolean hasSubquery();\r
+\r
+ /**\r
+ * Return whether or not an OptimizablePredicate contains a method call.\r
+ *\r
+ * @return boolean Whether or not an OptimizablePredicate includes a method call.\r
+ */\r
+ boolean hasMethodCall();\r
+\r
+ /**\r
+ * Tell the predicate that it is to be used as a column in the start key\r
+ * value for an index scan.\r
+ */\r
+ void markStartKey();\r
+\r
+ /** Is this predicate a start key? */\r
+ boolean isStartKey();\r
+\r
+ /**\r
+ * Tell the predicate that it is to be used as a column in the stop key\r
+ * value for an index scan.\r
+ */\r
+ void markStopKey();\r
+\r
+ /** Is this predicate a stop key? */\r
+ boolean isStopKey();\r
+\r
+ /**\r
+ * Tell the predicate that it is to be used as a qualifier in an index\r
+ * scan.\r
+ */\r
+ void markQualifier();\r
+\r
+ /** Is this predicate a qualifier? */\r
+ boolean isQualifier();\r
+\r
+ /**\r
+ * Is this predicate a comparison with a known constant value?\r
+ *\r
+ * @param optTable The Optimizable that we want to know whether we\r
+ * are comparing to a known constant.\r
+ * @param considerParameters Whether or not to consider parameters with defaults\r
+ * as known constants.\r
+ */\r
+ boolean compareWithKnownConstant(Optimizable optTable, boolean considerParameters);\r
+\r
+ /**\r
+ * Get an Object representing the known constant value that the given\r
+ * Optimizable is being compared to.\r
+ *\r
+ * @exception StandardException Thrown on error\r
+ */\r
+ DataValueDescriptor getCompareValue(Optimizable optTable) \r
+ throws StandardException;\r
+\r
+ /**\r
+ * Is this predicate an equality comparison with a constant expression?\r
+ * (IS NULL is considered to be an = comparison with a constant expression).\r
+ *\r
+ * @param optTable The Optimizable for which we want to know whether\r
+ * it is being equality-compared to a constant expression.\r
+ */\r
+ boolean equalsComparisonWithConstantExpression(Optimizable optTable);\r
+\r
+ \r
+ /**\r
+ * Returns if the predicate involves an equal operator on one of the\r
+ * columns specified in the baseColumnPositions.\r
+ *\r
+ * @param baseColumnPositions the column numbers on which the user wants\r
+ * to check if the equality condition exists.\r
+ * @param optTable the table for which baseColumnPositions are given.\r
+\r
+ @return returns the index into baseColumnPositions of the column that has the\r
+ equality operator.\r
+ */\r
+ int hasEqualOnColumnList(int[] baseColumnPositions,\r
+ Optimizable optTable)\r
+ throws StandardException;\r
+\r
+ /**\r
+ * Get a (crude) estimate of the selectivity of this predicate.\r
+ * This is to be used when no better technique is available for\r
+ * estimating the selectivity - this method's estimate is a hard-\r
+ * wired number based on the type of predicate and the datatype\r
+ * (the selectivity of boolean is always 50%).\r
+ *\r
+ * @param optTable The Optimizable that this predicate restricts\r
+ */\r
+ double selectivity(Optimizable optTable)\r
+ throws StandardException;\r
+\r
+ /**\r
+ * Get the position of the index column that this predicate restricts.\r
+ * NOTE: This assumes that this predicate is part of an\r
+ * OptimizablePredicateList, and that classify() has been called\r
+ * on the OptimizablePredicateList.\r
+ *\r
+ * @return The index position that this predicate restricts (zero-based)\r
+ */\r
+ int getIndexPosition();\r
+}\r
projects / Benchmarks_CSolver.git / blobdiff