Row-Class

A racket module which allows the creation and modification of object instances from database rows. These instances can be created, updated, and queried. This package is still very much a work in progress and may receive significant changes in the future. Currently only supports Mysql.

Usage

Setting up a class as a Row Object

Your class must extend row-object% and use the interface row-object-interface as seen here:

(define book%
  (class* row-object% (row-object-interface) 
    (init-field [id 1])
    (init-field [title 1])
    (init-field [author 1])
    (define/public (get-table-name) "books")
    (define/public (get-attributes) (list "id" "title" "author"))
    (super-new)))

row-object-interface requires that your class defines two methods:

get-table-name which returns a string with the name of the table representing this class

AND

get-attributes which lists the columns used by this class. NOTE: Currently the order of this list must be the same order of the init-field definitions. Every attribute in this list must also have a corresponding init-field definition.

Creating a new instance

You can create an instance of a row-object like you would any other object:

(define new-book (new book% [id 5] [title "Game of Thrones"] [author "GRR Martin"]))

The first time you persist an object to the database you must send it the create! method with a database connector:

(send new-book create! dbc)

After that, you can persist single attributes or the entire instances object set with save-attr! or save!:

(set-field! title new-book "A Dance with Dragons")
(send new-book save! dbc)

Querying for existing instances

You can get a list of all object instances of a given class with:

(make-from book% dbc)

Optionally, you can supply a where clause which will be passed to the SQL server:

(make-from book% dbc "id=2")

License

Standard MIT License:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

rohall / Row-Class