SQLiteStatement.java revision c8e1f23891cff31a9da2bab412631ff770a92f56 
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.SystemClock;
20
21/**
22 * A pre-compiled statement against a {@link SQLiteDatabase} that can be reused.
23 * The statement cannot return multiple rows, but 1x1 result sets are allowed.
24 * Don't use SQLiteStatement constructor directly, please use
25 * {@link SQLiteDatabase#compileStatement(String)}
26 */
27public class SQLiteStatement extends SQLiteProgram
28{
29    /**
30     * Don't use SQLiteStatement constructor directly, please use
31     * {@link SQLiteDatabase#compileStatement(String)}
32     * @param db
33     * @param sql
34     */
35    /* package */ SQLiteStatement(SQLiteDatabase db, String sql) {
36        super(db, sql);
37    }
38
39    /**
40     * Execute this SQL statement, if it is not a query. For example,
41     * CREATE TABLE, DELTE, INSERT, etc.
42     *
43     * @throws android.database.SQLException If the SQL string is invalid for
44     *         some reason
45     */
46    public void execute() {
47        if (!mDatabase.isOpen()) {
48            throw new IllegalStateException("database " + mDatabase.getPath() + " already closed");
49        }
50        long timeStart = SystemClock.uptimeMillis();
51        mDatabase.lock();
52
53        acquireReference();
54        try {
55            native_execute();
56            mDatabase.logTimeStat(mSql, timeStart);
57        } finally {
58            releaseReference();
59            mDatabase.unlock();
60        }
61    }
62
63    /**
64     * Execute this SQL statement and return the ID of the row inserted due to this call.
65     * The SQL statement should be an INSERT for this to be a useful call.
66     *
67     * @return the row ID of the last row inserted, if this insert is successful. -1 otherwise.
68     *
69     * @throws android.database.SQLException If the SQL string is invalid for
70     *         some reason
71     */
72    public long executeInsert() {
73        if (!mDatabase.isOpen()) {
74            throw new IllegalStateException("database " + mDatabase.getPath() + " already closed");
75        }
76        long timeStart = SystemClock.uptimeMillis();
77        mDatabase.lock();
78
79        acquireReference();
80        try {
81            native_execute();
82            mDatabase.logTimeStat(mSql, timeStart);
83            return (mDatabase.lastChangeCount() > 0) ? mDatabase.lastInsertRow() : -1;
84        } finally {
85            releaseReference();
86            mDatabase.unlock();
87        }
88    }
89
90    /**
91     * Execute a statement that returns a 1 by 1 table with a numeric value.
92     * For example, SELECT COUNT(*) FROM table;
93     *
94     * @return The result of the query.
95     *
96     * @throws android.database.sqlite.SQLiteDoneException if the query returns zero rows
97     */
98    public long simpleQueryForLong() {
99        if (!mDatabase.isOpen()) {
100            throw new IllegalStateException("database " + mDatabase.getPath() + " already closed");
101        }
102        long timeStart = SystemClock.uptimeMillis();
103        mDatabase.lock();
104
105        acquireReference();
106        try {
107            long retValue = native_1x1_long();
108            mDatabase.logTimeStat(mSql, timeStart);
109            return retValue;
110        } finally {
111            releaseReference();
112            mDatabase.unlock();
113        }
114    }
115
116    /**
117     * Execute a statement that returns a 1 by 1 table with a text value.
118     * For example, SELECT COUNT(*) FROM table;
119     *
120     * @return The result of the query.
121     *
122     * @throws android.database.sqlite.SQLiteDoneException if the query returns zero rows
123     */
124    public String simpleQueryForString() {
125        if (!mDatabase.isOpen()) {
126            throw new IllegalStateException("database " + mDatabase.getPath() + " already closed");
127        }
128        long timeStart = SystemClock.uptimeMillis();
129        mDatabase.lock();
130
131        acquireReference();
132        try {
133            String retValue = native_1x1_string();
134            mDatabase.logTimeStat(mSql, timeStart);
135            return retValue;
136        } finally {
137            releaseReference();
138            mDatabase.unlock();
139        }
140    }
141
142    private final native void native_execute();
143    private final native long native_1x1_long();
144    private final native String native_1x1_string();
145}
146