You can use
Axional Studio dictionary to define your database physical model and extend it by adding additional metadata
that will be used by application.
The physical dictionary/catalog is a repository containing the physical table structures of a database, as well as views and synonyms which form part of the data model. With tools provided by Axional Studio, a database can then be created using the model in question.
The types of data supported for the table columns are shown below.SQL Column Types
|char||[defined by user]|
|nchar||[defined by user]|
|varchar||[defined by user]|
|nvarchar||[defined by user]|
|lvarchar||[defined by user]|
Constraints are part of a database schema definition. A constraint is usually associated with a table and is created with a CREATE CONSTRAINT or CREATE ASSERTION SQL statement. They define certain properties that data in a database must comply with. They can apply to a column, a whole table, more than one table or an entire schema. A reliable database system ensures that constraints hold at all times (except possibly inside a transaction, for so called deferred constraints). Common kinds of constraints are:
- not null - each value in a column must not be NULL
- unique - value(s) in specified column(s) must be unique for each row in a table
- primary key - value(s) in specified column(s) must be unique for each row in a table and not be NULL; normally each table in a database should have a primary keyit is used to identify individual records
- foreign key - value(s) in specified column(s) must reference an existing record in another table (via it's primary key or some other unique constraint)
- check - an expression is specified, which must evaluate to true for constraint to be satisfied
We recommend that tables be created in XML, as this will allow the dictionary/catalog to transform the statements to various database engines (Informix, Oracle, Postgres, SQLServer, etc.). Direct SQL statements can be used, but will not be converted to other database formats.
The following table views are included:
- The Delta Change view, which indicates snapshots of the current physical definition of the table.
- The Conversion History view which indicates modifications using SQL statements of various types (ALTER_TABLE, etc.) and executed to upgrade the table to a newer catalog version. This view only shows those changes to the catalog which affect the table. Programmers should ensure that the conversions made with SQL statements match the changes made to table content in the catalog.
- A view of the table's catalog of labels.
- A view of the columns' catalog of labels.
- A view of the application objects which reference the table (include the table name in their SELECT or SQL statements).
- The Attributes view. Attributes determine how columns behave in a form or report, with a variety of options determining display, input, etc.
- The Soft Reference view shows the soft references which affect the table. Soft references are programmed references. They consist of lists of values in other tables' fields, related to the current table using SQL statements. They are used for more complex selection than simple foreign keys permit.
The relationships between tables, using foreign keys, can be shown graphically by pressing the Generate Graph button at the bottom of the form. The Delete button removes the graph created.