android - how to update or delet from database -

i new database created simple database .please let me know how delete single row data base , how edit single row database :) in advance

  void createdatabase(string time, string day,string course,string room,string syl){         database = openorcreatedatabase("newdb",mode_private, null);            sql = "create table if not exists examtab (time varchar ,day varchar ,course varchar ,room varchar ,syl varchar );";           c = database.rawquery(sql, null);          database.execsql(sql);       string insertsql = "insert examtab values('"+time+"','"+day+"','"+course+"','"+room+"','"+syl+"');";     database.execsql(insertsql);       database.close();   } 

create, delete, update : sqliteopenhelper « database « android

public dbadapter(context ctx) {     this.context = ctx;     dbhelper = new databasehelper(context);     }  private static class databasehelper extends sqliteopenhelper { databasehelper(context context) {   super(context, database_name, null, database_version); }  @override public void oncreate(sqlitedatabase db) {   try {     db.execsql(database_create);   } catch (sqlexception e) {     e.printstacktrace();   } }  @override public void onupgrade(sqlitedatabase db, int oldversion, int newversion) {   log.w(tag, oldversion + " " + newversion       + ", destroy old data");   db.execsql("drop table if exists contacts");   oncreate(db); }    public long insertcontact(string name, string email) {     contentvalues initialvalues = new contentvalues();     initialvalues.put(key_name, name);     initialvalues.put(key_email, email);     return db.insert(database_table, null, initialvalues);   }    public boolean deletecontact(long rowid) {     return db.delete(database_table, key_rowid + "=" + rowid, null) > 0;   }    public cursor getallcontacts() {     return db.query(database_table, new string[] { key_rowid, key_name,     key_email }, null, null, null, null, null);   }    public cursor getcontact(long rowid) throws sqlexception {     cursor mcursor = db.query(true, database_table, new string[] {     key_rowid, key_name, key_email }, key_rowid + "=" + rowid,     null, null, null, null, null);     if (mcursor != null) {       mcursor.movetofirst();     }     return mcursor;   }    public boolean updatecontact(long rowid, string name, string email) {     contentvalues args = new contentvalues();     args.put(key_name, name);     args.put(key_email, email);     return db.update(database_table, args, key_rowid + "=" + rowid,null)> 0;   } }