android - SQLiteConstraintException: error code 19: constraint failed -

i'm getting exception when insert in sqlite database

the following code gives me exception:

mdbhelper.createuser("pablo","a","a","a","a"); 

the code mdbhelper (mydbadapter):

private static final string user_table_create = "create table user ( email varchar, password varchar, fullname varchar, mobilephone varchar, mobileoperatingsystem varchar, primary key  (email))";  public long createuser(string email, string password, string fullname, string mobilephone, string mobileoperatingsystem)      {         contentvalues initialvalues = new contentvalues();         initialvalues.put("email",email);         initialvalues.put("password",password);         initialvalues.put("fullname",fullname);         initialvalues.put("mobilephone",mobilephone);         initialvalues.put("mobileoperatingsystem",mobileoperatingsystem);         return mdb.insert("user", null, initialvalues);     } 

the exception created on last line: return mdb.insert("user", null, initialvalues);

you inserting duplicate email.

plus recommended way have _id column primary key, if don't use it. way on future uses, use in adapter or list, won't have workaround.