DataClass

Syntax Element: types

Description

Declares the base types used by a database class.

Example

database SomeDatabase
{
  types 
    // logical name 'int', database name 'int', integer client type
    int as integer,
    // logical name 'number', database name 'numeric', real number client type
    number ("numeric") as real,
    // logical name 'nstring', database type 'nvarchar', string client type
    nstring ("nvarchar") as string;
    
  version 1.0 : initialized
  {
    design
    {
      public table T
      {
        public column C1 with DataType = type(int);
        public column C2 with DataType = type(int null);
        public column C3 with DataType = type(nstring(20));
        public column C4 with DataType = type(nstring(100) null);
        public column C5 with DataType = type(number(10, 3));
        public column C6 with DataType = type(number(12, 4) null);
      }
    }
  }
}

Notes

• Each base type is three-way mapping between logical name, database name, and client type. Base types do not always have enough information to identify a real type. That is why, when they are used to specify the type of a column or parameter, you must use the type operator.

Related Use Cases

• Specifying design separately from construction
• Getting compiler feedback on your database design
• Eliminating duplication between client and database code
• Keeping clients coupled to the current version
• Leveraging a version's proxy in a client
• Transition testing

Related Concepts

• Class of databases

Other Actions

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