SQL Reference

DLVALUE

>>-DLVALUE--(--data-location------------------------------------>
 
>----+---------------------------------------------+--)--------><
     '-,--linktype-string--+--------------------+--'
                           '-,--comment-string--'
 

The schema is SYSIBM.

The DLVALUE function returns a DATALINK value. When the function is on the right hand side of a SET clause in an UPDATE statement or is in a VALUES clause in an INSERT statement, it usually also creates a link to a file. However, if only a comment is specified (in which case the data-location is a zero-length string), the DATALINK value is created with empty linkage attributes so there is no file link.

data-location

If the link type is URL, then this is an expression that yields a varying length character string containing a complete URL value. If the expression is not an empty string and does not include the URL scheme and URL server, then the defaults of scheme "FILE" and the server name of the database server are included in the complete URL value.

linktype-string

An optional VARCHAR expression that specifies the link type of the DATALINK value. The only valid value is 'URL' (SQLSTATE 428D1).

comment-string

An optional VARCHAR(254) value that provides a comment or additional location information.

The result of the function is a DATALINK value. If any argument of the DLVALUE function can be null, the result can be null; If the data-location is null, the result is the null value.

When defining a DATALINK value using this function, consider the maximum length of the target of the value. For example, if a column is defined as DATALINK(200), then the maximum length of the data-location plus the comment is 200 bytes.

Example:

• Insert a row into the table. The URL values for the first two links are contained in the variables named url_article and url_snapshot. The variable named url_snapshot_comment contains a comment to accompany the snapshot link. There is, as yet, no link for the movie, only a comment in the variable named url_movie_comment.

    EXEC SQL  INSERT INTO HOCKEY_GOALS
                VALUES('Maurice Richard',
                      'Montreal Canadien',
                      '?',
                      'Boston Bruins,
                      '1952-04-24',
                      'Winning goal in game 7 of Stanley Cup final',
                       DLVALUE(:url_article),
                       DLVALUE(:url_snapshot, 'URL', :url_snapshot_comment),
                       DLVALUE('', 'URL', :url_movie_comment) );
  

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