DatabaseMetadata is also very poorly implemented in most drivers (postgreSQL
for example)
amrc
|-----Original Message-----
|From: [EMAIL PROTECTED]
|[mailto:[EMAIL PROTECTED]]On Behalf Of Aaron Mulder
|Sent: Wednesday, October 11, 2000 12:54 PM
|To: jBoss Developer
|Subject: Re: [jBoss-Dev] CVS
|update:jboss/src/main/org/jboss/ejb/plugins/jaws/jdbc
|JDBCInitCommand.java
|
|
| No! No!!!! *PLEASE* do not check the DatabaseMetaData! This can
|be VERY slow - 10 minutes or more - I've seen it! Sometimes I wake up in
|the middle of the night in a cold sweat thinking about that Oracle
|instance, but it was truly horrible and the DatabaseMetaData was too slow
|to be usable. :) Actually, I think I've seen that twice before, at
|different companies, with different horrible databases - but it's too
|common to ignore.
|
|Aaron
|
|On Wed, 11 Oct 2000, jBoss CVS Development wrote:
|> User: schulze
|> Date: 00/10/11 12:40:42
|>
|> Modified: src/main/org/jboss/ejb/plugins/jaws/jdbc
|> JDBCInitCommand.java
|> Log:
|> provided the PersistenceManager init() and destroy() methods
|with transactions, so that the table creation/deletion commands
|will affect the database.
|> Furthermore I replaced the ugly hack for the table detection
|in the JDBCInitCommand with a j2ee spec compilant version (should
|work with all drivers).
|>
|> Revision Changes Path
|> 1.7 +28 -23
|jboss/src/main/org/jboss/ejb/plugins/jaws/jdbc/JDBCInitCommand.java
|>
|> Index: JDBCInitCommand.java
|> ===================================================================
|> RCS file:
|/products/cvs/ejboss/jboss/src/main/org/jboss/ejb/plugins/jaws/jdbc
|/JDBCInitCommand.java,v
|> retrieving revision 1.6
|> retrieving revision 1.7
|> diff -u -r1.6 -r1.7
|> --- JDBCInitCommand.java 2000/09/28 01:17:04 1.6
|> +++ JDBCInitCommand.java 2000/10/11 19:40:41 1.7
|> @@ -14,7 +14,9 @@
|> import java.sql.ResultSet;
|> import java.sql.SQLException;
|> import java.sql.Statement;
|> +import java.sql.DatabaseMetaData;
|>
|> +
|> import org.jboss.ejb.plugins.jaws.JPMInitCommand;
|> import org.jboss.ejb.plugins.jaws.metadata.CMPFieldMetaData;
|>
|> @@ -26,7 +28,7 @@
|> * @author <a href="mailto:[EMAIL PROTECTED]">Marc Fleury</a>
|> * @author <a href="mailto:[EMAIL PROTECTED]">Joe Shevland</a>
|> * @author <a href="mailto:[EMAIL PROTECTED]">Justin Forder</a>
|> - * @version $Revision: 1.6 $
|> + * @version $Revision: 1.7 $
|> */
|> public class JDBCInitCommand
|> extends JDBCUpdateCommand
|> @@ -65,29 +67,32 @@
|> // Create table if necessary
|> if (jawsEntity.getCreateTable())
|> {
|> - boolean created = false;
|> - Connection con = null;
|> - Statement st = null;
|> - ResultSet rs = null;
|> - try {
|> - con = getConnection();
|> - st = con.createStatement();
|> - rs = st.executeQuery("SELECT COUNT(*) FROM
|"+jawsEntity.getTableName()+" WHERE 0=1");
|> - if(rs.next())
|> + // first check if the table already exists...
|> + // (a j2ee spec compatible jdbc driver has to fully
|> + // implement the DatabaseMetaData)
|> + boolean created = false;
|> + Connection con = null;
|> + ResultSet rs = null;
|> + try
|> + {
|> + con = getConnection();
|> + DatabaseMetaData dmd = con.getMetaData();
|> + rs = dmd.getTables(con.getCatalog(), null,
|jawsEntity.getTableName(), null);
|> + if (rs.next ())
|> created = true;
|> - rs.close();
|> - rs = null;
|> - st.close();
|> - st = null;
|> - con.close();
|> - con = null;
|> - } catch(SQLException e) {
|> - created = false;
|> - } finally {
|> - if(rs != null) try {rs.close();}catch(SQLException e) {}
|> - if(st != null) try {st.close();}catch(SQLException e) {}
|> - if(con != null) try
|{con.close();}catch(SQLException e) {}
|> - }
|> +
|> + rs.close ();
|> + con.close ();
|> + }
|> + catch(Exception e)
|> + {
|> + throw e;
|> + }
|> + finally
|> + {
|> + if(rs != null) try {rs.close(); rs =
|null;}catch(SQLException e) {}
|> + if(con != null) try {con.close();con =
|null;}catch(SQLException e) {}
|> + }
|>
|> // Try to create it
|> if(created) {
|>
|>
|>
|>
|
|
|
