MySQL Bugs: #87826: MySQL JDBC Connector/J DatabaseMetaData null pattern handling is non-compliant

Bug #87826	MySQL JDBC Connector/J DatabaseMetaData null pattern handling is non-compliant
Submitted:	21 Sep 2017 13:51	Modified:	4 Jan 2018 1:18
Reporter:	Simon Greatrix	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / J	Severity:	S3 (Non-critical)
Version:	8.0	OS:	Any
Assigned to:	Alexander Soklakov	CPU Architecture:	Any

Description:
The connection parameter nullNamePatternMatchesAll should default to true.

The JavaDoc page:

https://docs.oracle.com/javase/8/docs/api/java/sql/DatabaseMetaData.html

specifically states that:

Quote
Some DatabaseMetaData methods take arguments that are String patterns. These arguments all have names such as fooPattern. Within a pattern String, "%" means match any substring of 0 or more characters, and "_" means match any one character. Only metadata entries matching the search pattern are returned. If a search pattern argument is set to null, that argument's criterion will be dropped from the search.
Unquote

The JDBC Specification itself makes no comments either way about how null should be treated in these methods.

By having nullNamePatternMatchesAll default to false, the implementation is not compliant with the JavaDoc.

How to repeat:
Invoke:

DatabaseMetaData.getProcedureColumns("myCatalog","mySchema,"myProcedure",null);

Expected result - ResultSet describing all columns for the stored procedure.

Actual result - throws SQLException

Suggested fix:
Change the default for nullNamePatternMatchesAll

Hello Simon,

Thank you for the bug report.
Verified this behavior on MySQL Connector / J 8.0.7 dmr.

Thanks,
Chiranjeevi.

Hi Simon,

Thanks, is really makes sense to change nullNamePatternMatchesAll default back to true. And even remove nullNamePatternMatchesAll option from c/J 8.0.

http://bugs.mysql.com/bug.php?id=88091 marked as duplicate of this one.

The default value was changed in https://github.com/mysql/mysql-connector-j/commit/8d34e91534b3fe68aef9eca7ddff9602ef4c5e0d

Posted by developer:
 
Added the following entry to the Connector/J 8.0.9 changelog:

"The connection property nullNamePatternMatchesAll, when set to false (which was the default value), caused some DatabaseMetaData methods to throw an error when a null search string was used with them. The behavior was not compliant with the JDBC specification, which requires that a search criterion be ignored when a null search string is used for it. The connection property has now been removed from Connector/J 8.0."