[ http://issues.apache.org/jira/browse/DERBY-438?page=all ]
Daniel John Debrunner updated DERBY-438:
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Summary: Update triggers on tables with BLOB and CLOB columns fail at
execution time if the triggered-SQL-statement references the LOB column(s).
(was: Update triggers on tables with blob columns fail at execution time if the
triggered-SQL-statement references the blob column(s).)
> Update triggers on tables with BLOB and CLOB columns fail at execution time
> if the triggered-SQL-statement references the LOB column(s).
> ----------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-438
> URL: http://issues.apache.org/jira/browse/DERBY-438
> Project: Derby
> Type: Bug
> Components: SQL
> Versions: 10.1.1.0, 10.2.0.0, 10.0.2.2
> Reporter: A B
> Assignee: Daniel John Debrunner
> Fix For: 10.2.0.0
> Attachments: go.java
>
> Suppose I have 1) a table "t1" with blob data in it, and 2) an UPDATE trigger
> "tr1" defined on that table, where the triggered-SQL-action for "tr1"
> references the blob column from the updated ("new") row. Ex:
> create table t1 (id int, updated smallint, bl blob(32000));
> create trigger tr1 after update on t1 referencing new as n_row for each row
> mode db2sql values length(n_row.bl);
> Assuming that t1 has been populated with some data, then attempts to update
> t1 will fire the trigger, but the result will be one of the two following
> errors:
> 1) If blob data is < 32K...
> If the actual data in the table is less than 32K in length, the result will
> be:
> ERROR XCL12: An attempt was made to put a data value of type
> 'org.apache.derby.impl.jdbc.EmbedBlob' into a data value of type 'BLOB'.
> 2) If blob data is > 32K...
> If at least one row in the table has blob data that is longer than 32K (which
> means that Derby will stream it, so far as I can tell), then the error will
> be:
> ERROR XCL30: An IOException was thrown when reading a 'BLOB' from an
> InputStream.
> ERROR XJ001: Java exception: ': java.io.EOFException'.
> Note that for data larger than 32K, this error will occur regardless of
> whether or not the triggered-SQL-statement
> references the blob column.
> Surprisingly, it doesn't (appear to) matter what the trigger statement is
> actually doing--so long as it references the blob column at least once, one
> of these two errors will occur, depending on the length of the data. And if
> the data is greater than 32k, then the error will happen regardless of what
> the trigger does or whether or not it references the blob column.
> I looked at the documentation for UPDATE statements and TRIGGER statements,
> but nowhere did I see anything saying that either of these will not work with
> blobs. So as far as I can tell, both of the above scenarios should succeed...
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