SQLiteStatement.java revision 4dd4ab4cc322e82401f380aeb877daa4a20d7069 
1/*
2 * Copyright (C) 2006 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 android.database.sqlite;
18
19import android.os.Debug;
20import android.util.Log;
21
22/**
23 * A pre-compiled statement against a {@link SQLiteDatabase} that can be reused.
24 * The statement cannot return multiple rows, but 1x1 result sets are allowed.
25 * Don't use SQLiteStatement constructor directly, please use
26 * {@link SQLiteDatabase#compileStatement(String)}
27 */
28public class SQLiteStatement extends SQLiteProgram
29{
30    private static final String TAG = "SQLiteStatement";
31
32    /**
33     * Don't use SQLiteStatement constructor directly, please use
34     * {@link SQLiteDatabase#compileStatement(String)}
35     * @param db
36     * @param sql
37     */
38    /* package */ SQLiteStatement(SQLiteDatabase db, String sql) {
39        super(db, sql);
40    }
41
42    /**
43     * Execute this SQL statement, if it is not a query. For example,
44     * CREATE TABLE, DELTE, INSERT, etc.
45     *
46     * @throws android.database.SQLException If the SQL string is invalid for
47     *         some reason
48     */
49    public void execute() {
50        long timeStart = Debug.threadCpuTimeNanos();
51        mDatabase.lock();
52
53        acquireReference();
54        try {
55            if (SQLiteDebug.DEBUG_SQL_STATEMENTS) {
56                Log.v(TAG, "execute() for [" + mSql + "]");
57            }
58            if (SQLiteDebug.DEBUG_CAPTURE_SQL) {
59                Log.v(TAG, SQLiteDebug.captureSql(mDatabase.getPath(), mSql, getBindArgs()));
60            }
61            native_execute();
62            mDatabase.logTimeStat(mSql, timeStart);
63        } finally {
64            releaseReference();
65            mDatabase.unlock();
66        }
67    }
68
69    /**
70     * Execute this SQL statement and return the ID of the most
71     * recently inserted row.  The SQL statement should probably be an
72     * INSERT for this to be a useful call.
73     *
74     * @return the row ID of the last row inserted.
75     *
76     * @throws android.database.SQLException If the SQL string is invalid for
77     *         some reason
78     */
79    public long executeInsert() {
80        long timeStart = Debug.threadCpuTimeNanos();
81        mDatabase.lock();
82
83        acquireReference();
84        try {
85            if (SQLiteDebug.DEBUG_SQL_STATEMENTS) {
86                Log.v(TAG, "executeInsert() for [" + mSql + "]");
87            }
88            if (SQLiteDebug.DEBUG_CAPTURE_SQL) {
89                Log.v(TAG, SQLiteDebug.captureSql(mDatabase.getPath(), mSql, getBindArgs()));
90            }
91            native_execute();
92            mDatabase.logTimeStat(mSql, timeStart);
93            return mDatabase.lastInsertRow();
94        } finally {
95            releaseReference();
96            mDatabase.unlock();
97        }
98    }
99
100    /**
101     * Execute a statement that returns a 1 by 1 table with a numeric value.
102     * For example, SELECT COUNT(*) FROM table;
103     *
104     * @return The result of the query.
105     *
106     * @throws android.database.sqlite.SQLiteDoneException if the query returns zero rows
107     */
108    public long simpleQueryForLong() {
109        long timeStart = Debug.threadCpuTimeNanos();
110        mDatabase.lock();
111
112        acquireReference();
113        try {
114            if (SQLiteDebug.DEBUG_SQL_STATEMENTS) {
115                Log.v(TAG, "simpleQueryForLong() for [" + mSql + "]");
116            }
117            if (SQLiteDebug.DEBUG_CAPTURE_SQL) {
118                Log.v(TAG, SQLiteDebug.captureSql(mDatabase.getPath(), mSql, getBindArgs()));
119            }
120            long retValue = native_1x1_long();
121            mDatabase.logTimeStat(mSql, timeStart);
122            return retValue;
123        } finally {
124            releaseReference();
125            mDatabase.unlock();
126        }
127    }
128
129    /**
130     * Execute a statement that returns a 1 by 1 table with a text value.
131     * For example, SELECT COUNT(*) FROM table;
132     *
133     * @return The result of the query.
134     *
135     * @throws android.database.sqlite.SQLiteDoneException if the query returns zero rows
136     */
137    public String simpleQueryForString() {
138        long timeStart = Debug.threadCpuTimeNanos();
139        mDatabase.lock();
140
141        acquireReference();
142        try {
143            if (SQLiteDebug.DEBUG_SQL_STATEMENTS) {
144                Log.v(TAG, "simpleQueryForString() for [" + mSql + "]");
145            }
146            if (SQLiteDebug.DEBUG_CAPTURE_SQL) {
147                Log.v(TAG, SQLiteDebug.captureSql(mDatabase.getPath(), mSql, getBindArgs()));
148            }
149            String retValue = native_1x1_string();
150            mDatabase.logTimeStat(mSql, timeStart);
151            return retValue;
152        } finally {
153            releaseReference();
154            mDatabase.unlock();
155        }
156    }
157
158    private final native void native_execute();
159    private final native long native_1x1_long();
160    private final native String native_1x1_string();
161}
162