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From Mamta Satoor <msat...@gmail.com>
Subject Re: [PATCH] Jira-189 ResultSetMetaData.getSchemaName and ResultSetMetaData.isWritable donot return correct values
Date Tue, 05 Apr 2005 21:50:11 GMT
I guess, it will help to actually attach the patch. 


On Apr 5, 2005 1:40 PM, Mamta Satoor <msatoor@gmail.com> wrote:
> Hi,
> I have sent 2 patches for Derby engine code in the past(and they are
> already commited) in preparation for making updatable resultset
> functionality available in Network Server mode. Here is another patch
> to make progress towards that goal.
> The problem is that Derby does not return correct values for
> ResultSetMetaData.getSchemaName and ResultSetMetaData.isWritable. And
> these 2 methods are crucial to have updatable resultset functionality
> under Network Server mode.
> Following is the description of the issue from Jira
> "Derby Net Client and JCC driver rely on getSchemanName method to
> construct the correct "update where current of sql" for an updatRow.
> For eg, if the user is in say schema s1 and the updatable resultset is
> issued on a table from schema s2 with the sql "select c11 from s2.t1
> for update". Currenly, getSchemaName returns null and hence, the
> client code constructs a sql like "update t1 ... where current of
> ...". ie the update is being issued against table t1 in schema s1.
> getSchemaName should return s2, so the driver can correctly genereat
> sql as "update s2.t1 ... where current of ...".
> In addition, the client code lets a user issue an updateXXX on a
> column only if the column is writable and it determines that by
> looking at the return value of isWritable(). Derby engine currently
> always returns false for this method and because of that, updateXXX
> fails in Network Server mode. Derby should return true for the columns
> which can be updated in the given resultset. For eg for "select c11,
> c12 from t1 for update of c11", isWritable should return true for c11
> and false for c12. "
> Most of the changes in this patch are to add methods and variables
> related to  schema name and writable status to columns so they are
> available correctly to EmbedResultSetMetaData.java. These changes went
> into ResultColumn.java, VirtualColumnNode.java, BaseColumnNode.java,
> ColumnReference.java, ValueNode.java, GenericColumnDescriptor.java,
> ColumnDescriptor.java, ResultColumnDescriptor.java
> CursorNode.java currently marks the columns updatable in FromTable
> object only. The columns need to be marked correctly in
> ResultSetColumnList associated with the cursor also. That is what the
> change in CursorNode.java does.
> ResultColumnList.java currently doesn't handle marking columns
> updatable for the column list associated with a cursor node. Added
> markColumnsInSelectListUpdatableByCursor method to handle that.
> Change in EmbedResultSet.java is to catch updateXXX on read-only
> columns of the resultset. Have added test for this.
> Change in EmbedResultSetMetaData.java is have isWritable method return
> the column's updatableByCursor state. And to call the correct schema
> name method on the column in getSchemaName method.
> svn stat
> M      java\engine\org\apache\derby\impl\sql\compile\ResultColumn.java
> M      java\engine\org\apache\derby\impl\sql\compile\VirtualColumnNode.java
> M      java\engine\org\apache\derby\impl\sql\compile\CursorNode.java
> M      java\engine\org\apache\derby\impl\sql\compile\BaseColumnNode.java
> M      java\engine\org\apache\derby\impl\sql\compile\ColumnReference.java
> M      java\engine\org\apache\derby\impl\sql\compile\ValueNode.java
> M      java\engine\org\apache\derby\impl\sql\compile\ResultColumnList.java
> M      java\engine\org\apache\derby\impl\sql\GenericColumnDescriptor.java
> M      java\engine\org\apache\derby\impl\jdbc\EmbedResultSet.java
> M      java\engine\org\apache\derby\impl\jdbc\EmbedResultSetMetaData.java
> M      java\engine\org\apache\derby\iapi\sql\dictionary\ColumnDescriptor.java
> M      java\engine\org\apache\derby\iapi\sql\ResultColumnDescriptor.java
> M      java\testing\org\apache\derbyTesting\functionTests\tests\lang\updatableResultSet.java
> M      java\testing\org\apache\derbyTesting\functionTests\master\DerbyNet\updatableResultSet.out
> M      java\testing\org\apache\derbyTesting\functionTests\master\DerbyNet\resultset.out
> M      java\testing\org\apache\derbyTesting\functionTests\master\DerbyNetClient\updatableResultSet.out
> M      java\testing\org\apache\derbyTesting\functionTests\master\DerbyNetClient\resultset.out
> M      java\testing\org\apache\derbyTesting\functionTests\master\updatableResultSet.out
> M      java\testing\org\apache\derbyTesting\functionTests\master\jdk14\updatableResultSet.out
> M      java\testing\org\apache\derbyTesting\functionTests\master\resultset.out
> If no objection from anyone, can a commiter commit this patch?
> thanks,
> Mamta

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