[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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