How to check if a value already exists in the database in Android

Question

I\'ve a database that I will populate with items after I parse a JSON response. How can I check if the values are already present in the database and prevent inserting again

Answer 1

In your example table:

When you create your table you can set your name as unique (if that is what you want unique) with the following (Using a SQLiteOpenHelper).

String createPlayerTable = "create table " +
                TIME_REPORT +
                " (" +
                USER_ID + " integer primary key autoincrement not null," +
                CLIENT_NAME + " text not null," +                    
                "UNIQUE("+CLIENT_NAME+")"+
                ");";

Then in you insert insertIntoDatabase method use

db.insertOrThrow(TIME_REPORT, null, initialValues);

instead of

db.insert(TIME_REPORT, null, initialValues);

This may throw a SQLiteConstraintException so you will have add a try/catch.

Hope this is what you need.

Answer 2

1 )if your looking for the unique id than make your id field as auto increment and insert only name value

2 ) if you are not looking for unique than retrieve the all data for this table store in the array than compare your inserted value with existing value in data base

Answer 3

Create an object that will hold your data, eg. ClientData
Create a method for fetching all data from the database

public List<ClientData> selectAll() {
   List<ClientData> list = new ArrayList<ClientData>();
   Cursor cursor = this.myDataBase.query(TABLE_NAME, new String[] { "userID, clientName" },
   null, null, null, null, null);
   if (cursor.moveToFirst()) {
        do {
           list.add(new ClientData(cursor.getString(0), cursor.getString(1)));
         } while (cursor.moveToNext());
   }
   if (cursor != null && !cursor.isClosed()) {
         cursor.close();
   }
   return list;
}

Before executing your insert statements, fetch all data and then check if data exists:

if (!list.contains(clientData)) {
    executeInsert();
}

I am not sure if SQLite supports stored procedures, but if it does, you could write a stored procedure for that as well.