Android中SQLite操作示例
Android中SQLite操作示例
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在Android中对SQLite数据库的操作，涉及以下几个方面：
1、确认数据库文件，即.db文件；
2、通过android.database.sqlite.SQLiteDatabase类的openOrCreateDatabase()方法打开数据库；
3、数据库操作：
A、开始事务：SQLiteDatabase.beginTransaction();
B、执行sql语句；
C、结束事务：SQLiteDatabase.endTransaction()；
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具体代码可参考如下：
static boolean installDefaultSitesToDB(Context cxt) {// 确认目标数据库文件File path = cxt.getDir("databases", Context.MODE_WORLD_WRITEABLE);path = new File(path, "db_name.db");SQLiteDatabase db = null;try { // 打开数据库 ?db = openDB(path.getAbsolutePath());if (db == null) {//Log.e("tag", "open db_name.db ERROR~");return false;}db.beginTransaction();//开始事务 boolean bool = doInstallData(db);//执行sql语句，插入数据 //设置事务标志 if (bool) {db.setTransactionSuccessful();// 设置事务标志} else {//Log.w("tag", "doInstall.DEFAULT_SITES Fail~!");}return bool;} finally {if (db != null) { //结束事务if (db.inTransaction()) {db.endTransaction();}db.close();}}}private static SQLiteDatabase openDB(String file) {try {//SQLiteDatabase.openOrCreateDatabase(file, null);int flag = SQLiteDatabase.OPEN_READWRITE;flag = flag | SQLiteDatabase.CREATE_IF_NECESSARY;flag = flag | SQLiteDatabase.NO_LOCALIZED_COLLATORS;SQLiteDatabase db = SQLiteDatabase.openDatabase(file, null, flag);return db;} catch (Throwable e) {//Log.e("tag","openDatabase error:" + e.getMessage());return null;}}//private static boolean doInstallData(SQLiteDatabase db) {try {//create tableString sql = "CREATE TABLE IF NOT EXISTS Permissions (origin TEXT UNIQUE NOT NULL, allow INTEGER NOT NULL)";db.execSQL(sql);ContentValues cv = new ContentValues();for (String site : DEFAULT_SITES) {cv.clear();cv.put("origin", site);cv.put("allow", 1);long ret = db.insertOrThrow("Permissions", null, cv);Log.d("tag", "db.insert.RET:" + ret);}return true;} catch (SQLException se) {String msg = "doInstall.error:[%s].%s";Log.d("tag",String.format(msg, se.getClass(),se.getMessage()));return false;}}