db_string { -default "*none*" } sqlWhat it does:
Returns the first column of the result of the SQL query $sql. If the query doesn't return a row, returns $default (or raises an error if no $default is provided).Defined in: /web/philip/packages/acs-core/10-database-procs.tcl
Source code:
arg_parser_for_db_string $args db_with_handle db { set selection [ns_db 0or1row $db $sql] if { [empty_string_p $selection] } { if { [string compare $default "*none*"] } { return $default } error "Selection did not return a value, and no default was provided" } return [ns_set value $selection 0] }