It's really not equivalent. Your Case 2 was:
<c:set var="nullValue" value="null"/>
Which sets nullValue to the String literal "null". I suggested the equivalent
of:
<c:set var="nullValue" value="${null}"/>
Which will set nullValue to null (meaning that nullValue will actually be
removed from page scope). Did you actually try it and got the same error?
Quoting Derek Mahar <[EMAIL PROTECTED]>:
> Your solution is equivalent to Case 2 that I listed in my original
> message. The Microsoft SQL Server JDBC driver complains with a
> JspException:
>
> javax.servlet.ServletException: javax.servlet.jsp.JspException:
> INSERT INTO tblTest(a) VALUES (?)
> : [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]Syntax error
> converting the nvarchar value 'null' to a column of data type int.
>
> However, the JDBC driver accepts and correctly processes the following
> query:
>
> <sql:update>
> INSERT INTO tblTestDerek VALUES (null)
> </sql:update>
>
> In light of this, I suspect that there may be an error in the
> implementation of <sql:param> where it treats "null" as a string
> argument rather than as an SQL null argument.
>
> Derek
>
> -----Original Message-----
> From: Kris Schneider [mailto:[EMAIL PROTECTED]
> Sent: May 18, 2004 9:10 PM
> To: Tag Libraries Users List
> Subject: Re: [JSTL] How do I enter a null value with <sql:param>?
>
>
> <sql:param value="${null}"/>
>
> Derek Mahar wrote:
> > How do I enter a null value into a table column with <sql:param>? The
>
> > JSTL 1.1 specification states for <sql:param> that, "If value is null,
>
> > the parameter is set to the SQL value NULL." However, no matter what
> > value I pass to <sql:param>, I'm unable to set a null column:
> >
> > Case 1: Set value to undefined variable
> > <sql:update>
> > INSERT INTO tblTest(a) VALUES (?)
> > <sql:param value="${nullValue}"/>
> > </sql:update>
> >
> > Output:
> > javax.servlet.ServletException: javax.servlet.jsp.JspException:
> > INSERT INTO tblTest(a) VALUES (?)
> > : [Microsoft][SQLServer 2000 Driver for JDBC]The specified SQL type is
>
> > not supported by this driver.
> >
> > Case 2: Set value to "null"
> > <c:set var="nullValue" value="null"/>
> > <sql:update>
> > INSERT INTO tblTest(a) VALUES (?)
> > <sql:param value="${nullValue}"/>
> > </sql:update>
> >
> > Output:
> > javax.servlet.ServletException: javax.servlet.jsp.JspException:
> > INSERT INTO tblTest(a) VALUES (?)
> > : [Microsoft][SQLServer 2000 Driver for JDBC][SQLServer]Syntax error
> > converting the nvarchar value 'null' to a column of data type int.
> >
> > Cast 3: Set value to empty string
> > <c:set var="nullValue" value=""/>
> > <sql:update>
> > INSERT INTO tblTest(a) VALUES (?)
> > <sql:param value="${nullValue}"/>
> > </sql:update>
> >
> > Output:
> > Microsoft SQL Server inserts a new row with column a set to 0.
> >
> > Any suggestions?
> >
> > Derek
>
> --
> Kris Schneider <mailto:[EMAIL PROTECTED]>
> D.O.Tech <http://www.dotech.com/>
--
Kris Schneider <mailto:[EMAIL PROTECTED]>
D.O.Tech <http://www.dotech.com/>
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