1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License 15 */ 16 17 package com.android.providers.contacts.database; 18 19 import com.android.providers.contacts.util.NeededForTesting; 20 21 /** 22 * Static methods for database operations. 23 */ 24 public class MoreDatabaseUtils { 25 26 /** 27 * Builds a CREATE INDEX ddl statement for a given table and field. 28 * 29 * @param table The table name. 30 * @param field The field to index. 31 * @return The create index sql statement. 32 */ 33 public static String buildCreateIndexSql(String table, String field) { 34 return "CREATE INDEX " + buildIndexName(table, field) + " ON " + table 35 + "(" + field + ")"; 36 } 37 38 /** 39 * Builds a DROP INDEX ddl statement for a given table and field. 40 * 41 * @param table The table name that was originally used to create the index. 42 * @param field The field that was originally used to create the index. 43 * @return The drop index sql statement. 44 */ 45 @NeededForTesting 46 public static String buildDropIndexSql(String table, String field) { 47 return "DROP INDEX IF EXISTS " + buildIndexName(table, field); 48 } 49 50 /** 51 * The index is created with a name using the following convention: 52 * <p> 53 * [table name]_[field name]_index 54 */ 55 public static String buildIndexName(String table, String field) { 56 return table + "_" + field + "_index"; 57 } 58 59 /** 60 * Build a bind arg where clause. 61 * <p> 62 * e.g. Calling this method with value of 4 results in: 63 * <p> 64 * "?,?,?,?" 65 * 66 * @param numArgs The number of arguments. 67 * @return A string that can be used for bind args in a sql where clause. 68 */ 69 @NeededForTesting 70 public static String buildBindArgString(int numArgs) { 71 final StringBuilder sb = new StringBuilder(); 72 String delimiter = ""; 73 for (int i = 0; i < numArgs; i++) { 74 sb.append(delimiter).append("?"); 75 delimiter = ","; 76 } 77 return sb.toString(); 78 } 79 } 80
