Using Caché Objects - InterSystems Documentation

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Data Types
Caché supports a number of data types for variables, where each data type is itself a class.
Each data type class represents a specific literal type, such as a string or integer. These data
type classes determine the behavior of both object properties and fields in relational tables.
Caché also allows you to create your own data types.
Data type classes provide the following features:
• They provide for SQL, ODBC, ActiveX, and Java interoperability by providing SQL
logical operation, client data type, and translation information.
• They provide validation for literal data values, which you can extend or customize by
using data type class parameters.
• They manage the translation of literal data for its stored (on disk), logical (in memory),
and display formats.
Data type classes differ from other classes in a number of ways:
• They cannot be instantiated or stored independently.
• They cannot contain properties.
• They support a specific set of methods (called the data type interface), which is described
below.
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