how to display duplicate entry

[olcaygul]

hii i´m learning jsp and html with sql and i´m beginer on it,
i have the table andcodes below in mysql and jsp, i´m working on html and jsp with netbeans IDE 3.6. of course if i try to insert any thing into that table 2. time, i get a error message: java.sql.SQLException: Invalid argument value: Duplicate entry......

and i want to display that duplicate value with some warning message (value is already exist or something like that)
can any one help me on it, how to do that?????
regards

1-sql codes;

create table team
            (team_id int not null AUTO_INCREMENT,
            team_fahrer_name VARCHAR (80),
            team_arbeiter_name VARCHAR (80),
            team_fahrzeug_kenntzeichen VARCHAR (80),
            team_beschreibung VARCHAR (80),
            PRIMARY KEY (team_id),
            UNIQUE KEY team_fahrer_name (team_fahrer_name),
            UNIQUE KEY team_arbeiter_name (team_arbeiter_name),
            UNIQUE KEY team_fahrzeug_kenntzeichen (team_fahrzeug_kenntzeichen))TYPE = INNODB;
 

2-javabean;

public void neuenteam_einfuegen(){
 
        String fahrer_name = this.getfahrer_name();
        String arbeiter_name = this.getarbeiter_name();
        String fahrzeug_kennzeichen = this.getfahrzeug_kenntzeichen();
        String fahrt_typ = this.getfahrt_typ();
 
            dbop= new DBOperationen();
            dbop.dbverbindung();
        String sql="insert into team (team_fahrer_name, team_arbeiter_name, team_fahrzeug_kenntzeichen, team_beschreibung) values ";
        sql+="(\""+fahrer_name+"\",\""+arbeiter_name+"\",\""+fahrzeug_kenntzeichen+"\",\""+fahrt_typ+"\");";
        System.out.println(sql);
        dbop.executeupdate(sql);
 

[chaarmann]

just make a try-catch statement around your "dbop.executeupdate(sql); " statement. Inside the catch-part, print your warning message.

Be aware that all different errors are thrown that you need to care about in your catch-statement, like the database is down, or the network connection is blocked etc.). So just to test for duplicate primary keys, there is another way:
1.) lock the database table for writing
2.) inquire if one of the primary keys is already there (select * from team where team_fahrer_name=... or team_arbeiter_name=... or ...).
3.) if you get some records (=results) back, then print a warning only. Else, that means if there is no record returned, execute your update-statement.
4.) unlock database

[olcaygul]

@chaarmann
thanx thanx thanx,
solved the problem