Question

我只使用过一个表的SQLite。我现在需要一个有两个表的数据库。我现在就是这样做的：

public class MySQLiteHelper extends SQLiteOpenHelper {

    public static final String TABLE_CAT = "cats";
    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_CAT = "cat";

    private static final String DATABASE_NAME = "cats.db";
    private static final int DATABASE_VERSION = 1;

    private static final String DATABASE_CREATE = "create table "
            + TABLE_CAT + "( " + COLUMN_ID
            + " integer primary key autoincrement, " + COLUMN_CAT
            + " text not null)";

    public MySQLiteHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(DATABASE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(MySQLiteHelper.class.getName(),
                "Upgrading database from version " + oldVersion + " to "
                        + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_CAT);
        onCreate(db);
    }

}

除了名为“cats”的表之外，我想要一个名为“items”的行，它们具有相同的行。需要改变什么呢？

注意：此应用程序仍在测试中，因此我无需担心更新数据库版本。

Answer 1

为什么你不能做两个查询，比如

private static final String DATABASE_CREATE_TABLE_ONE = "create table "
            + TABLE_CAT1 + "( " + COLUMN_ID
            + " integer primary key autoincrement, " + COLUMN_CAT1
            + " text not null)";

private static final String DATABASE_CREATE_TABLE_TWO = "create table "
            + TABLE_CAT2 + "( " + COLUMN_ID
            + " integer primary key autoincrement, " + COLUMN_CAT2
            + " text not null)";

并在你的onCreate方法中：

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(DATABASE_CREATE_TABLE_ONE );
    db.execSQL(DATABASE_CREATE_TABLE_TWO );
}

在同一个类中创建两个SQLite表

1 个答案: