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NAME: dbcolsource
FUNCTION:
Return a pointer to the name of the database column from which
the specified regular result column was derived.
SYNTAX:
char *dbcolsource(dbproc, colnum)
DBPROCESS *dbproc;
int colnum;
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COMMENTS:
o dbcolsource() is one of the DB-Library browse mode routines.
It is usable only with results from a browse-mode SELECT (i.e.,
a SELECT containing the key words FOR BROWSE). See the Intro-
duction for a detailed discussion of browse mode.
o dbcolsource() provides an application with information it needs
to update a database column, based on an ad hoc query. SELECT
statements may optionally specify header names for regular
(i.e., non-compute) result columns:
select author = au_lname from authors for browse
When updating a table, you must use the database column name,
not the header name (in this example, "au_lname", not
"author"). You can use the dbcolsource() routine to get the
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underlying database column name:
dbcolsource(dbproc, 1)
This call will return a pointer to the string "au_lname".
o dbcolsource() is useful for ad hoc queries. If the query has
been hardcoded into the program, this routine is obviously
unnecessary.
o The application can call dbcolsource() any time after
dbresults().
o Example 7 in the DB-Library Reference Supplement contains a
call to dbcolsource().
PARAMETERS:
dbproc - A pointer to the DBPROCESS structure that provides the
connection for a particular front-end/SQL Server process. It
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contains all the information that DB-Library uses to manage
communications and data between the front end and SQL Server.
colnum - The number of the result column of interest. Column
numbers start at 1.
RETURNS:
A pointer to a null-terminated column name. This pointer will be
NULL if the column number is out of range or if the column is the
result of a SQL expression, such as "max(colname)".
SEE ALSO:
dbcolbrowse, dbqual, dbtabbrowse, dbtabcount, dbtabname, dbtab-
source, dbtsnewlen, dbtsnewval, dbtsput