[This section is under construction!]

SQueaL & Delight

SQueaL is an XML-based SQL Schema designed for defining databases used in web development. XML is used to define data types, databases, and tables.

Delight is an object-oriented interface designed around SQueaL. Delight wraps up database access functionality in a simple and intuitive interface taking advantage of SQueaL SQL Schema.

SQL Schema's XML based nature allows it to not only be used in the Alt Framework but to easily integrate with other languages and graphical designers.

SQL Schema

The SQL Schema is the heart of SQueaL. It provides a standard and robust type and structural schematic for data sources.

Although the intention is to provide a layer of abstraction from SQL databases, SQL Schema can be used for any kind of data.

SQL Schema is made of three main components: the type system, the standard type library, and the table structure system.

Type System

The SQL Schema type system is the subset of SQL Schema that allows you to define data types.

A type in SQL Schema has the following:

  • Some form of data storage
  • Constraints to determine validate data input
  • Methods for working with the type (editing, displaying, analyzing)
  • Values that can be assigned to the type (constants or SQL functions)
  • A base type to inherit all of the above from

The type system provides an XML structure to define all of the above, while leaving the actual implementation of methods, sql types, and sql functions to the program.


Standard Type Library

While type system defines the language for defining types, the standard type library is a series of commonly used types defined using the type system. The standard type library abstracts many of the common SQL types:

  • Integer
  • Real
  • String
  • Date
  • Time
  • Timestamp
  • Binary
  • Enum
  • Set

The standard type library makes it easy to build databases without any knowledge of the underlying type implementation. Since types can inherit from other types, more complex types can be made by inheriting from standard types (such as a URL type inheriting from the String type).


Table Structure

Once types are defined, tables can be defined as well. A table is defined as a collection of fields, links to other tables, and other tables.

Legacy Documentation

Documentation for SQueaL and Delight was created before it became part of the Alt Framework project. Until that documentation is revised and integrated into this web site, read about SQueaL and Delight on its current web site.

page last updated: Thursday, February 14, 2008

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