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
17package com.android.providers.contacts.database;
18
19import com.android.providers.contacts.util.NeededForTesting;
20
21/**
22 * Static methods for database operations.
23 */
24public 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