[hibernate-issues] [Hibernate-JIRA] Resolved: (HHH-3873) DB2Dialect.getLimitString raise DB2 error message when called with limit=0

[Strong Liu (JIRA)]

     [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-3873?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Strong Liu resolved HHH-3873.
-----------------------------

       Resolution: Fixed
    Fix Version/s: 4.0.0.Alpha1
                   3.6.1

> DB2Dialect.getLimitString raise DB2 error message when called with limit=0
> --------------------------------------------------------------------------
>
>                 Key: HHH-3873
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3873
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.3.1
>         Environment: DB2,
> http://viewvc.jboss.org/cgi-bin/viewvc.cgi/hibernate/core/branches/Branch_3_3/core/src/main/java/org/hibernate/dialect/DB2390Dialect.java?revision=15070&view=markup&pathrev=15216
> http://viewvc.jboss.org/cgi-bin/viewvc.cgi/hibernate/core/branches/Branch_3_3/core/src/main/java/org/hibernate/dialect/DB2400Dialect.java?revision=15070&view=markup&pathrev=15216
>            Reporter: Julien Kronegg
>            Assignee: Strong Liu
>            Priority: Minor
>             Fix For: 3.6.1, 4.0.0.Alpha1
>
>   Original Estimate: 4h
>  Remaining Estimate: 4h
>
> Executing a query called with setMaxResults(n) makes the underlying Hibernate code to call DB2Dialect.getLimitString.
> While this is working fine in general case, the following database error is raised when setting the maximum number of results to zero:
>     SqlException: NUMBER 0 DIRECTLY SPECIFIED IN AN SQL STATEMENT IS OUTSIDE THE RANGE OF ALLOWABLE VALUES IN THIS CONTEXT (1, 2147483647) 
> This is due to the getLimitString method in classes DB2400Dialect and DB2390Dialect : 
> 	public String getLimitString(String sql, int offset, int limit) {
> 		return new StringBuffer(sql.length() + 40)
> 			.append(sql)
> 			.append(" fetch first ")
> 			.append(limit)
> 			.append(" rows only ")
> 			.toString();
> 	}
> When the limit parameter is set to zero, the fetch limit is appended, which explains why the error message occur.
> Solution:
> ------------
> When the limit is 0, there should be no "fetch first" instruction appended (as 0 is the general convention for "no limit"). The code would be:
> 	public String getLimitString(String sql, int offset, int limit) {
> +              if (limit==0) return sql;
> 		return new StringBuffer(sql.length() + 40)
> 			.append(sql)
> 			.append(" fetch first ")
> 			.append(limit)
> 			.append(" rows only ")
> 			.toString();
> 	}
> Workaround: 
> ------------------
> In order to avoid the error message, getLimitString(n) or setMaxResults(n) should be called with the 'newN' argument:
>     int newN = (n==0?Integer.MAX_VALUE:n);
> Note: since the workaround is quite easy, I set the priority to "Minor"

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