NAME

DBIx::Simple::Batch::Documentation::Directives

DESCRIPTION

The power behind DBIx::Simple::Batch lies in the sql files and their commands. Each commands will contain a single directive which instructs the sql file processor to perform some function. Commands are processed in the order in which they appear in the sql file. The document will explain each directive and provide an example of its usage.

SYNOPSIS

The sql file to be processed may contain any text you desire, e.g. comments and other markup. DBIx::Simple::Batch only reacts to command lines (commands). These instructions (or commands) must be placed on its own line and be prefixed with an exclamation point, a space, the command, another space, and the statement to be evaluated.

e.g. ! execute select * from foo ! execute { select * from foo }

Multiple commands can be used in a single sql file. Multi-line commands are supported but its statements must be enclosed with `{}` curly brackets having the closing bracket appear on its own line as the first character.

DIRECTIVES

The following is a list of available directive, their usage and syntax:

connect

! connect:
     This command creates or replaces the database connection using a
     typical DBI connection string seperated by comma. A blank username or 
     password field should be denoted with a single dash `-`.
e.g.
! connect dbi:mysql:test:localhost, user, pass, { RaiseError => 1, PrintError => 2 }

execute

! execute:
     This command simply execute the supplied sql statement.

e.g.
! execute update foo set name = $!name

capture

! capture:
     This is an execute command who's dataset will be cached (stored)
     for later use. Note! This command can only be used with a select
     statement.

e.g.
! capture select * from foo

replace

! replace:
     This is an execute command that after successfully executed,
     replaces the currently scoped parameters with data from the last
     row in its dataset. Note! This command can only be used with a
     select statement.
   
e.g.
! replace select 'foo' as `foo`, 'bar' as `bar`, 'baz' as `baz`

include

! include:
     This command processes the supplied sql file in a sub transaction.
     Note A! The included sql file is isolated from the current
     processing. Any capture commands encountered in the included sql
     files will not have it's dataset cached unless the setname directive
     is used to provide a specific reference name to the resultset.
     Note B! The included sql file will use the currently scoped
     variables to process the included sql file unless a comma-seperated
     list of variables are used with the sql file name.

e.g.
! include foo/bar.sql
! include foo/bar.sql foo, bar, baz

proceed

! proceed:
     This command should be read "proceed if" because it evaluates the
     string passed (perl code) for truth, if true, it continues if
     false it skips to the next proceed command or until the end of
     the sql file.
     
e.g.
! proceed $!count > 5
! ...
! forward 5
! proceed 1
! forward 0
! ...

ifvalid

! ifvalid: [validif:]
     These commands are synonyms for proceed and exist for readability.

storage

! storage:
     This command does absolutely nothing except store the sql
     statement in the commands list (queue) for processing individually
     from within the perl code with a method like process_command.
     
e.g.
! storage insert into foo (this, that) values ('foo', 'bar')

declare

! declare:
     This command is effectively equivalent to the `select .. into` sql
     syntax and uses an sql select statement to add vairables to the
     scope for processing.

e.g.
! declare select 'foo' as `foo`, 'bar' as `bar`, 'baz' as `baz`

forward

! forward:
     This command takes an index and jumps to that command line and
     continues from there. Similar to a rewind or fast forward function
     for the command queue.
     
e.g.
# endless loop
! ...
! ...
! forward 0

process

! process:
     This command takes an index and executes that command line.

e.g.
# run the first command twice
! ...
! process 0

perl -e

! perl -e:
     This command passes the statement to perl's eval function which
     can evaluate perl code and scoped runtime variables.

e.g.
! perl -e $!count > 5

examine

! examine:
     This command is used for debugging, it errors out with the
     compiled statement passed to it.
     
e.g.
! examine select * from foo where id = $!id

setname

! setname:
     This command is used to set a name to recall the reference of
     the next captured resultset. If this seems confusing don't worry,
     it's easier to use than to explain.
     
e.g.
! setname foo

PROJECT

DBIx-Simple-Batch - Alternative to ORM and Stored Procedures

PROJECT DESCRIPTION

DBIx::Simple::Batch is formerly DBIx::Simple::Procedure.

This module allows your program to process text files containing one or many commands that execute SQL statements sequentially. Please keep in mind that DBIx::Simple::Batch is an alternative to database stored procedures and not a replacement or emulation of them. Essentially it is an interface to execute and return data from multiple queries with some logic.

PROJECT POD URL

http://app.alnewkirk.com/pod/projects/dbix/simple/batch/

AUTHOR

Al Newkirk, <awncorp at cpan.org>

BUGS

Please report any bugs or feature requests to Al Newkirk, <awncorp at cpan.org>. I will respond in the order they are processed.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc DBIx::Simple::Batch

or email the developer at:

Al Newkirk, C<< <awncorp at cpan.org> >>

ACKNOWLEDGEMENTS