how to check the database

[flyclassic22]

May i know how can i abstract every data from all the rows under a specific column?

When i use this SQL query statemnt, "SELECT Name FROM StudentRecord", this will return ROWS of record under the column "Name". So if i want to store every data into a variable, how can i do it?

When i use this SQL query statement, "SELECT * FROM StudentRecord WHERE Name="Hello", and if in the database there isnt a record with the "Name" as "Hello", will ResultSet return a null and how can i handle this error?

Please direct me. Thanks

 

[Hattusas]

You can try writing all of the fields in your db table
for example there are 4 fields (name,surname,number,id )
the you can try typing (select name,surname,number,id from (your table name> ).

the result set WILL NOT return null.
resultSet.getString,getInt,getDouble of course will return null but the class itself is not null.To solve this ,act in this way below:
java.sql.ResultSet rs = stmt.executeQuery("your query"
while (rs.next())
{
//in that block you are sure that there is at least 1 row
//of your query
} Salih Sipahi
Software Engineer.
City of Istanbul Turkey
ssipahi@yonbilgi.com

 

[flyclassic22]

hmm i don't understand..
let's say i've this to display records of my 6 field database in to JTextFields(name jtff) using sql query when i trigger a button, it will display a records whenever avaliable in the JtextFields, but how do i loop throughout the database table to check if there isn't any records and popup a message and say "record not found"
any idea? PLease advise.. thanks



public void display(ResultSet rs)
{
try {
rs.next();

int recordNumber = rs.getInt( 1 );

if ( recordNumber != 0 ) {
jtff1.setText( String.valueOf( recordNumber));
jtff2.setText( rs.getString( 2 ) );
jtff3.setText( rs.getString( 3 ) );
jtff4.setText( rs.getString( 4) );
jtff5.setText( rs.getString( 5 ) );
jtff6.setText( rs.getString( 6 ) );
}
}
catch ( SQLException sqlex ) {
sqlex.printStackTrace();
}
}

 

[flyclassic22]

to be in more detail, i mean, search for the criteria for eg. "name" and it doesn't match any records, i would like to display "record not found"

 

[palbano]

if( !rs.next())
  System.out.println("No Records found");
else
  display(rs);

does that help?
-pete

 

[flyclassic22]

wow, that's easy! hehe
thanks alottttttttttttttttttttttt!!! million thanks..