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How to make a movie like a pro...
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DBIx::DBStag::SQLTemplate(3pm) User Contributed Perl Documentation DBIx::DBStag::SQLTemplate(3pm) NAME
DBIx::DBStag::SQLTemplate - A Template for an SQL query SYNOPSIS
# find template by name $template = $dbh->find_template("mydb-personq"); # execute this template, filling in the 'name' attribute $xml = $dbh->selectall_xml(-template=>$template, -bind=>{name => "fred"}); DESCRIPTION
A template represents a canned query that can be parameterized. Templates are collected in directories (in future it will be possible to store them in files or in the db itself). To tell DBStag where your templates are, you should set: setenv DBSTAG_TEMPLATE_DIRS "$HOME/mytemplates:/data/bioconf/templates" Your templates should end with the suffix .stg, otherwise they will not be picked up You can name templates any way you like, but the standard way is to use 2 or 3 fields SCHEMA-OBJECT or SCHEMA-OBJECT-QUALIFIERS (with underscores used within fields) A template file should contain at minimum some SQL; for example: Example template 1 SELECT studio.*, movie.*, star.* FROM studio NATURAL JOIN movie NATURAL JOIN movie_to_star NATURAL JOIN star WHERE [movie.genre = &genre&] [star.lastname = &lastname&] USE NESTING (set(studio(movie(star)))) Thats all! However, there are ways to make your template more useful Example template 2 :SELECT studio.*, movie.*, star.* :FROM studio NATURAL JOIN movie NATURAL JOIN movie_to_star NATURAL JOIN star :WHERE [movie.genre = &genre&] [star.lastname = &lastname&] :USE NESTING (set(studio(movie(star)))) // schema: movie desc: query for fetching movies By including : at the beginning it makes it easier for parsers to assemble SQL (this is not necessary for DBStag however) After the // you can add tag: value data. You should set schema: if you want the template to be available to users of a db that conforms to that schema GETTING A TEMPLATE The DBIx::DBStag object gives various methods for fetching templates by name, by database or by schema VARIABLES WHERE clause variables in the template look like this &foo& variables are bound at query time my $set = $dbh->selectall_stag(-template=>$t, -bind=>["bar"]); or my $set = $dbh->selectall_stag(-template=>$t, -bind=>{foo=>"bar"}); If the former is chosen, variables are bound from the bind list as they are found OPTIONAL BLOCKS WHERE [ foo = &foo& ] If foo is not bound then the part between the square brackets is left out Multiple option blocks are ANDed together An option block need not contain a variable - if it contains no &variable& name it is automatically ANDed BINDING OPERATORS The operator can be bound at query time too WHERE [ foo => &foo& ] Will become either WHERE foo = ? or WHERE foo LIKE ? or WHERE foo IN (f0, f1, ..., fn) Depending on whether foo contains the % character, or if foo is bound to an ARRAY METHODS
name Usage - $name = $template->name Returns - str Args - every template has a name that (should) uniquely identify it desc Usage - $desc = $template->desc Returns - str Args - templates have optional descriptions get_varnames Usage - $varnames = $template->get_varnames Returns - listref of strs Args - Returns the names of all variable used in this template WEBSITE
<http://stag.sourceforge.net> AUTHOR
Chris Mungall <cjm@fruitfly.org> COPYRIGHT
Copyright (c) 2003 Chris Mungall This module is free software. You may distribute this module under the same terms as perl itself perl v5.12.4 2010-02-01 DBIx::DBStag::SQLTemplate(3pm)
