Philip Crow > Bigtop > Bigtop::Backend::SQL

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NAME ^

Bigtop::Backend::SQL - defines legal keywords in table and field blocks

SYNOPSIS ^

If you are making an SQL generating backend:

    use Bigtop::Backend::SQL;

This specifies the valid keywords for the SQL generating backend.

If you need additional keywords which are generally useful, add them here (and send in a patch). If you need backend specific keywords, register them within your backend module. Note that only keywords affecting the SQL should be put here. But, fields have other keywords which affect things like how they look in html forms and whether they are fetched by default. Register those keywords in Bigtop::Control:: or Bigtop::Model:: modules.

DESCRIPTION ^

If you are using a Bigtop backend which generates SQL, you should read this document to find out what the valid keywords inside table and field blocks are.

If you are writing a Bigtop backend to generate SQL, you should use this module. That will register the standard table and field keywords with the Bigtop parser.

BASIC STRUCTURE ^

A bigtop app block could look like this:

    app name {
        table name {
            field name {
            }
        }
    }

KEYWORDS ^

Inside the table, you can include the following keywords:

sequence

This must be the name of a valid sequence defined with an app level sequence block. Any field whose 'is' list includes auto (which is an alias for assign_by_sequence) will use this sequence.

data

Allows you to include data for table population. Include as many column name => value pairs as you need. Repeat for each row you want to insert. They will become INSERT INTO statements.

Example:

    table payeepayor {
        field id    { is int, primary_key, assign_by_sequence; }
        field name  { is varchar; }
        sequence payeepayor_seq;
        data
            name => `Gas Company`;
        data
            id   => 2,
            name => `Electric Company`;
    }

Note that it is not wise to manually assign ids for tables with sequence defaults. I show it here as a simple syntactic example.

Be somewhat careful with quoting. Numbers won't be quoted, but strings will be. If you need internal quotes, escape them as in:

    data name => `Phil\'s Business Center`;

Double quotes don't need escaping, since the value will be single quoted.

Inside the field you may include

is (required)

This defines the basic SQL declaration for the column. Provide a comma separated list of SQL column definition phrases or put them all in a back quoted string or use some combination of those. There are some keywords you can use, these are translated by the backend to their proper equivalents:

int

Short for int4.

primary_key

Not very short for PRIMARY KEY.

assign_by_sequence

Short for defaults to the next value from the sequence for this table. To use this, you must have a defined sequence for the table and that sequence must be defined at the app level. (Defining it twice seems odd to me, but some tables must share an index. The app level definition creates the sequence, as in it generates 'CREATE SEQUENCE...'. The table level definition ties this table to a sequence, as in it generates a default clause with the sequence in it.)

auto

A pure synonymn for assign_by_sequence, for those who refuse to type so long a keyword.

update_with

Not currently supported.

refers_to

This marks the column as a foreign key (whether a genuine SQL foreign key is used is up to the backend). Currently, you can only specify the table this column points to. The assumption about which column varies depending on who's doing the assuming. For example, Class::DBI assumes the column refers to the primary key of the other table. Gantry makes the tacit assumption that the primary key is the single column called id.

AUTHOR ^

Phil Crow <crow.phil@gmail.com>

COPYRIGHT and LICENSE ^

Copyright (C) 2005 by Phil Crow

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.6 or, at your option, any later version of Perl 5 you may have available.

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