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 ?

Eg. Name of Database: Exicom.sqlite

Name of table: TimeReport

Fields in Database: userID, clientName

I am using SQLite in android.

Thanks for your input

This is my HELPER class. I've skipped opening and closing the database as it will be too long. Followed up by where I will call the method to insert values into the database.

public static final String indexNo = "index_no";
public static final String user_id = "userId";
public static final String company_id = "companyId";
public static final String user_name = "username";
public static final String client_Id = "clientId";
public static final String project_Id = "projectId";
public static final String report_Id = "reportId";
public static final String niv_1  = "niv1";
public static final String niv_2 = "niv2";
public static final String work_type_id = "workTypeId";
public static final String time_type_id = "timeTypeId";
public static final String date_id = "dateId";
public static final String month_id = "monthId";
public static final String year_id = "yearId";
public static final String hourS = "hours";
public static final String private_comment = "privateComment";
public static final String Ncomment = "comment";
public static final String mod_flag = "modFlag";
public static final String new_flag = "newFlag";
public static final String open_flag = "openFlag";
public static final String delete_flag = "deleteFlag";

private static final String DATABASE_NAME = "CopernicusDB.sqlite";
private static final String DATABASE_TABLE = "TimeReportTable";
private static final int    DATABASE_VERSION = 1;

private final Context context;
private static DatabaseHelper DBHelper;
private static SQLiteDatabase db;
private static String TAG = "##---SecondActivityUserHelper---##";
public SecondActivityUserHelper(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}

private static class DatabaseHelper extends SQLiteOpenHelper{

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        Log.v(TAG,"The DatabaseHelper method ");
    }

    public long insertIntoDatabase(String companyId,String username, String dateId,
            String clientId,String projectId,String niv1,String niv2,String workTypeId,String timeTypeId,
            String hours,String comment,String privateComment,String openFlag,String reportId) 
            {
            ContentValues initialValues = new ContentValues();
            initialValues.put(company_id, companyId);
            initialValues.put(user_name, username);
            initialValues.put(date_id,dateId);
            initialValues.put(client_Id,clientId);
            initialValues.put(project_Id,projectId);
            initialValues.put(niv_1,niv1);
            initialValues.put(niv_2,niv2);
            initialValues.put(work_type_id,workTypeId);
            initialValues.put(time_type_id,timeTypeId);
            initialValues.put(hourS, hours);
            initialValues.put(Ncomment, comment);
            initialValues.put(private_comment,privateComment);
            initialValues.put(open_flag, openFlag);
            initialValues.put(report_Id,reportId);
            Log.v(TAG, "Inserted into database sucessfully");
            return db.insert(DATABASE_TABLE, null, initialValues);
            }

}

useradapter.openDatabase();
long id = dB.insertIntoDatabase(  newcompanyid,newusername,newdate,
newClientId,newprojectId,newniv1,newniv2,newworktypeid,newtimetypeid,
newhours,newcomment,newprivatecomment,newopen,newreportid);
                             useradapter.closeDatabase();

score 4 · Accepted Answer · answered Oct 19 '11 at 12:09

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.

score 1 · Answer 2 · answered Oct 19 '11 at 12:03

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

score 1 · Answer 3 · answered Oct 19 '11 at 12:41

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.

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

3 Answers3

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