My app has two buttons, the first button is for deleting record on user input and the second button is for deleting all records. But when I want to delete data it shows the message
“Your application has been forcefully stopped”.
Please check my code and give me some suggestion.
public void deleteAll()
{
//SQLiteDatabase db = this.getWritableDatabase();
// db.delete(TABLE_NAME,null,null);
//db.execSQL("delete * from"+ TABLE_NAME);
db.execSQL("TRUNCATE table" + TABLE_NAME);
db.close();
}
and
public void delete(String id)
{
String[] args={id};
getWritableDatabase().delete("texts", "_ID=?", args);
}
But it shows the following Log cat error.
03-07 15:57:07.143: ERROR/AndroidRuntime(287): Uncaught handler: thread main exiting due to uncaught exception
03-07 15:57:07.153: ERROR/AndroidRuntime(287): java.lang.NullPointerException
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at com.example.MySQLiteHelper.delete(MySQLiteHelper.java:163)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at com.example.Settings$4.onClick(Settings.java:94)
-07 15:57:07.153: ERROR/AndroidRuntime(287): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:158)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at android.os.Handler.dispatchMessage(Handler.java:99)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at android.os.Looper.loop(Looper.java:123)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at android.app.ActivityThread.main(ActivityThread.java:4203)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at java.lang.reflect.Method.invokeNative(Native Method)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at java.lang.reflect.Method.invoke(Method.java:521)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549)
03-07 15:57:07.153: ERROR/AndroidRuntime(287): at dalvik.system.NativeStart.main(Native Method)
You missed a space: db.execSQL("delete * from " + TABLE_NAME);
Also there is no need to even include *, the correct query is:
db.execSQL("delete from "+ TABLE_NAME);
Answer：
db.delete(TABLE_NAME, null, null);
or, if you want the function to return the count of deleted rows,
db.delete(TABLE_NAME, "1", null);
From the documentation of SQLiteDatabase delete method:
To remove all rows and get a count pass “1” as the whereClause.
Answer：
To delete all the rows within the table you can use:
db.delete(TABLE_NAME, null, null);
Answer：
SQLite doesn’t support the TRUNCATE command. You should use what you’ve tried in the previous line:
DELETE FROM `TABLE_NAME`;
P.S. You can optimize your program by using the same instance of the database connection for all of your queries to the given database instead of creating a new one for every query.
Answer：
There’s no need to use “execute” function.The following code worked for me:::
db.delete(TABLE_NAME,null,null);
db.close();
Answer：
SQLiteDatabase db = this.getWritableDatabase();
db.execSQL("DELETE FROM tablename"); //delete all rows in a table
db.close();
this work for me 🙂
Answer：
try this code to delete all data from a table..
String selectQuery = "DELETE FROM table_name ";
Cursor cursor = data1.getReadableDatabase().rawQuery(selectQuery, null);
Answer：
use Sqlit delete function with last two null parameters.
db.delete(TABLE_NAME,null,null)
Answer：
I use this class to handle database.I hope it will help some one in future.
Happy coding.
}
Usage:
Answer：
Just Write
or
Answer：
Answer：
Answer：
This is working for me. The difference is here with execSQL and rawQuery. The rawQuery use most in searching case and execSQL mostly used in apply operations.
Answer：
Can be usefull.
Answer：
this metod delate all data from database
Answer：
I have a function that works for me in Unity (in conjunction with the database SQLite).
code C#:
Answer：
Here is simple way to delete:
Here whereClause is optional, passing null will delete all rows in table. delete function will return number of affected row if whereClause passed otherwise will return 0.
Important Note: If you want to remove all rows and require count of deleted ones also then pass 1 as
whereClause.
Tags: androidandroid, sql, sqlite
