As a core developer of BasePeer, but someone who is having trouble finding
the time to follow these discussions carefully, I am going to make a
suggestion. Please tell me nicely why the following will not work:
Add transaction functionality to BasePeer as I specified a while back. This
should be quite generally useful code. I assume I will have some need for
it in the future and will add it when I need it, but if others are needing
it now, why not submit the code.
Add the postgres specific code regarding the object_data column in the peer
where it is being updated. I have no objection to this update being
generically a transaction if it is handled gracefully in the db's that don't
support transactions (maybe there is a metadata property on transaction
support). Otherwise add specific code for postgres here.
John McNally
----- Original Message -----
From: Nissim <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, June 26, 2000 4:04 PM
Subject: [PATCH] Postgresql (long)
> Hi all,
>
> This is about how to get the large object stuff working in turbine.
> there's a bunch of patches, and some of the stuff isn't all that clean,
> but I'd need some suggestions because cleaning it up might require
> changes to public interfaces...
>
> First of all, to run turbine with pgsql, you have to get the newest
> pgsql JDBC driver, and then apply a patch to it. Find the patch here:
> http://www.mail-archive.com/turbine%40list.working-dogs.com/msg02249.html
>
> Note: if you use OID for something other than large object references
> and you need it to look like an int in the JDBC metadata this patch will
> break that. If you have no idea what that means, you're probably safe
> using it.
>
> Next I have patches for turbine, because to read or write object data
> from postgres, you must be within a transaction. The following code
> adds some stuff to the DB interface, and the BasePeer to check if the
> database you're using requires this functionality, and then to create
> the transaction if you do.
>
> <Questions for turbine coders>
> 1) In the BasePeer.doUpdate, we can check whether the table(s) getting
> updated contain an object column, and only execute the transaction then,
> but in the executeQuery method we don't have access to the table names,
> so we have to make the transaction every time if it's postgres, should
> we try to fix that? We'd have to get the connection from the pool in
> the doSelect method, and then pass it to the executeQuery, but that
> would change the interface...should we add another executeQuery method
> that takes a Connection param?
>
> 2) To test whether a column is objectdata, we don't have the SQL type,
> so I just check if it's not instanceof String, Date or Number then it's
> objectdata...should we add the SQL type to the columnMap...it's not
> easy, because of all the public helper methods have the same interface
> as the new methods would have...because length is an int and
> java.sql.Types.* are ints...
> </Questions for turbine coders>
>
> Thanks
>
> -Nissim
>
> Patches:
>
> Index: docs/schemas/Postgres_users_roles_permissions.sql
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/docs/schemas/Postgres_users_roles_permissions.
sql,v
> retrieving revision 1.1
> diff -r1.1 Postgres_users_roles_permissions.sql
> 83c83
> < OBJECTDATA varchar (255), -- oder doch bytea???
> ---
> > OBJECTDATA oid,
> Index: src/java/org/apache/turbine/om/peer/BasePeer.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/om/peer/BasePeer.j
ava,v
> retrieving revision 1.25
> diff -r1.25 BasePeer.java
> 867a868,879
> >
> > Statement stmt = null;
> > boolean doTransaction = DBBroker.getInstance()
> > .getDB( dbName )
> > .objectDataNeedsTrans();
> > if (doTransaction)
> > {
> > stmt = connection.createStatement();
> > stmt.executeUpdate("BEGIN TRANSACTION");
> > stmt.close();
> > }
> >
> 870a883,890
> >
> > if (doTransaction)
> > {
> > stmt = connection.createStatement();
> > stmt.executeUpdate("COMMIT TRANSACTION");
> > stmt.close();
> > }
> >
> 1062a1083,1100
> >
> > Statement stmt = null;
> > boolean doTransaction = false;
> > if ( db.objectDataNeedsTrans() )
> > {
> > for (int i = 0; i<tables.size(); i++)
> > {
> > doTransaction = doTransaction ||
> > containsObjectColumn(dbMap,
tables.get(i));
> > }
> > }
> >
> > if ( doTransaction )
> > {
> > stmt = dbCon.createStatement();
> > stmt.executeUpdate("BEGIN TRANSACTION");
> > stmt.close();
> > }
> 1122a1161,1168
> >
> > if ( doTransaction )
> > {
> > stmt = dbCon.createStatement();
> > stmt.executeUpdate("COMMIT TRANSACTION");
> > stmt.close();
> > }
> >
> 1230a1277,1289
> > }
> >
> > /**
> > * Determines whether any of the columns in the table are object
> > * (binary) data.
> > *
> > * @return true if the table contains a column which will be a SQL
> > * large object.
> > */
> > public static boolean containsObjectColumn(DatabaseMap dbMap, String
tableName) throws Exception
> > {
> > TableMap tmap = dbMap.getTable(tableName);
> > return tmap.containsObjectColumn();
> Index: src/java/org/apache/turbine/util/db/map/TableMap.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/map/TableM
ap.java,v
> retrieving revision 1.6
> diff -r1.6 TableMap.java
> 181a182,199
> > * Returns true if this tableMap contains a column with object data.
> > */
> > public boolean containsObjectColumn()
> > {
> > Enumeration e = columns.elements();
> > while (e.hasMoreElements())
> > {
> > Object theType = ((ColumnMap)e.nextElement()).getType();
> > if (! ( theType instanceof String ||
> > theType instanceof Number ||
> > theType instanceof java.util.Date ) )
> > {
> > return true;
> > }
> > }
> > return false;
> > }
> > /**
> Index: src/java/org/apache/turbine/util/db/pool/DB.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DB.ja
va,v
> retrieving revision 1.8
> diff -r1.8 DB.java
> 123a124,126
> > /** The method is used to chek whether
> > writing large objects to the DB requires a transaction. */
> > public abstract boolean objectDataNeedsTrans();
> Index: src/java/org/apache/turbine/util/db/pool/DBDB2App.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBDB2
App.java,v
> retrieving revision 1.4
> diff -r1.4 DBDB2App.java
> 145a146,153
> >
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBHypersonicSQL.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBHyp
ersonicSQL.java,v
> retrieving revision 1.3
> diff -r1.3 DBHypersonicSQL.java
> 131a132,139
> >
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBInstantDB.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBIns
tantDB.java,v
> retrieving revision 1.5
> diff -r1.5 DBInstantDB.java
> 128a129,135
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBInterbase.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBInt
erbase.java,v
> retrieving revision 1.1
> diff -r1.1 DBInterbase.java
> 136a137,143
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBMM.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBMM.
java,v
> retrieving revision 1.5
> diff -r1.5 DBMM.java
> 134a135,142
> >
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBOracle.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBOra
cle.java,v
> retrieving revision 1.5
> diff -r1.5 DBOracle.java
> 133a134,141
> >
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBPostgres.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBPos
tgres.java,v
> retrieving revision 1.4
> diff -r1.4 DBPostgres.java
> 146a147,153
> > /**
> > * Returns true because transactions are necessary in postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return true;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBSybase.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBSyb
ase.java,v
> retrieving revision 1.3
> diff -r1.3 DBSybase.java
> 132a133,140
> >
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
> Index: src/java/org/apache/turbine/util/db/pool/DBWeblogic.java
> ===================================================================
> RCS file:
>
/products/cvs/turbine/turbine/src/java/org/apache/turbine/util/db/pool/DBWeb
logic.java,v
> retrieving revision 1.4
> diff -r1.4 DBWeblogic.java
> 126a127,133
> > /**
> > * Returns false because transactions are only necessary in
postgres.
> > */
> > public boolean objectDataNeedsTrans()
> > {
> > return false;
> > }
>
>
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