How to avoid inserting duplicate's into SQLite data base?

I am getting contact information from server when i login through account. i am storing those information in SQLite, when user login second time, I don't want to same duplicate contact inserting again into SQLite.

i tried like this but not working

boolean exist= contact_db.CheckItem(entry.getUser());               
if(!exist) {
 // insert
}else {
 // don't insert

code in DB class

Cursor mCursor = database.query(ContactsDB.TABLE_CONTACTS, allColumns,
                    ContactsDB.CONTACT_USERID + "= ' " + name +"'" , null, null, null, null);
    if (mCursor != null && mCursor.moveToFirst()) 
        return false;
    else return true;

How to avoid the duplicates while inserting the contacts into data base?


Better would be to create a UNIQUE index for that column using UNIQUE Keyword. An example can be found here and also a simpler one can be found here.

After creating table you have to create a UNIQUE INDEX for row as,

CREATE UNIQUE INDEX idx_something ON Table_name 
                                          (column_name_1, column_name_2,....);

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