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使用sqlite3在android中创建数据库的问题

[英]Problems in creating database in android using sqlite3

I am using sqlite3 for creating database using SQLiteOpenHelper class but unable to create database. 我正在使用sqlite3使用SQLiteOpenHelper类创建数据库,但无法创建数据库。 The code which is used is given as below: 给出的代码如下:

public class ABCHelper extends SQLiteOpenHelper {

public static final String TABLE_COMMENTS = "comments";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_COMMENT = "comment2";

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

// Database creation sql statement
private static final String DATABASE_CREATE = "create table "
        + TABLE_COMMENTS + "(" + COLUMN_ID
        + " integer primary key autoincrement, " + COLUMN_COMMENT
        + " text not null);";

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

@Override
public void onCreate(SQLiteDatabase database) {
    database.execSQL(DATABASE_CREATE);
    Log.d("EventsData", "onCreate: " + DATABASE_CREATE);
}

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

如果将“文本”更改为VARCHAR(255)怎么办?

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