Apps How to clear database?


Hi, All..
I have ChatApp.
All message save in local database.

When user press button "Log out" i need clear data about chats and contacts from DB.
I am clearing my shared_prefs(Log Out) and call clearMethod():
public void onClear(SQLiteDatabase db) {
        db.execSQL("DROP TABLE IF EXISTS " + Contact.TABLE_NAME);
        db.execSQL("DROP TABLE IF EXISTS " + ChatSessions.TABLE_NAME);
        db.execSQL("DROP TABLE IF EXISTS " + ChatSessions.FK_TABLE_NAME);
        db.execSQL("DROP TABLE IF EXISTS " + Message.TABLE_NAME);
When i try login - i see all my previous chats(DB si CLEAR).

When i call Settings > Manage Applications> Menu button > Filter by Running. > Select Myapplication > Force stop
and try login - all OK - chatlist is clear!

How to correct clear database?
Calling Force stop - is very hard way ((


Thread starter

Can't you just "DELETE FROM TABLE xxxx" ?

If I run these command tables will be cleared. But App still running and I can view all data from DB in my app(chatlists, all contacts etc.. )...
Only when I do "Force stop" and try run - then my app will be use clear DB.

Another option is to delete the whole database: context.deleteDatabase(DATABASE_NAME);

In these case my app is down, but in Settings > Manage Applications> Menu button > Filter by Running. > Select Myapplication
button "Force stop" is active.....

Does it possible to clear db and reinitialize my app to view clear lists(chat, contacts etc)?


Well-Known Member
I'm not sure what the problem is. When you say you can still see it, do you mean from within the application using "SELECT"? Or externally from a database viewer?

If you "DELETE FROM TABLE xxx" and commit, then it should be gone. If you can still do a "SELECT" and see the data, then either you didn't delete the right data or you didn't commit and it rolled back.

In my application I call the deleteDatabase(name) command and it physically deletes the database, I just then create a new one.

When I tried to use DROP, it didn't seem to do anything, at least it didn't free up any physical space. Try DELETE and not DROP
hi, i just want to know if you're asking how to delete the whole database or a single form? because it's so easy to clear the whole database even without asking, you just need to learn it from yourself.

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Why don't you turn your code the initially reads the database, and populates the program into a method. Then call that method after you have cleared out the databases. Sounds like you are clearing the databases, but not reloading the data into the program (even blank data).