RE: [JDBC] Questión of JDBC

Miguel Angel wrote:
> I am a programmer in java and I want to design a module that
> allows me to read the consultations that I make within poststoneware
> without concerning the amount of columns nor the name of the same ones.
> So my question is:
> Within the JDBC that class allows me to obtain this data of the
> consultations that I make to the data base?

Sorry, I don't understand this at all, but I'll read on,
maybe it will become clear from the examples:

> Something thus:
> SELECT * FROM tableA INNER JOIN tableB USING(column);
>
> columnA | columnB
> ------------------
> 10 | 20
>
> I need this:
>
> query
> -------
> columnA
> columnB
>
> This can be obtained by means of the JDBC?

Do you want to get the java.sql.ResultSetMetaData of the query?

That can be had with java.sql.ResultSet.getMetaData(), see
http://java.sun.com/j2se/1.5.0/docs/api/java/sql/ResultSet.html#getMetaData()

The ResultSetMetaData will give you the names chosen for the
result columns.

Or do you want to get the names of the columns of a table?

That can be obtained with the following PostgreSQL query:

SELECT column_name
FROM information_schema.columns
WHERE table_name='mytable' AND table_schema='myschema'
ORDER BY ordinal_position;

This will be of limited protability, because not all database systems
have an information_schema (although they should).

Maybe the following technique is more portable:

SELECT * FROM myschema.mytable WHERE 0=1;

This will select zero rows, you can get the ResultSetMetaData of the
(empty) ResultSet and figure out the column names.

If none of these answers your question,
please try to clarify it.

Yours,
Laurenz Albe