Sunday, January 13, 2019

Database Properties for Type shape (Definition)

Database Properties for Type shape (Definition)

Use these options to create named and unnamed row types that act as reusable type definitions for tables or views.

Named row types are based on the SQL specification of tables, called typed tables, and are identified within the system as persistent type storage. Unnamed row types are not identified as persistent type storage.

Row types create composite data types that can be used in models that will be implemented on object relational databases. A row type can be specified as the data type.

Name

Type a name for the composite type that will appear on the Data Type tab of the Column Properties dialog box and in the Types window.

By default, a suffix is added to the name to distinguish its type based on the selection under Composite type.

Named row type

Select to specify that the type is not an alias of any other type.

Distinct type

Select to specify that the type is based on another type and has the same representation as the type on which it is based, but is an entirely distinct type of its own.

If you select this option, you will not be able to select options on the Fields category.

Domain

Select to specify that the type is an alias of another type; it is an indirect representation of the same type.

If you select this option, you will not be able to select options on the Fields category.

Note: When you select Domain, the Alias Collection Type option becomes available.

Alias collection type (visible only if Domain is selected)

Select an option to specify whether an attribute's value is a collection of a single value, set, list, or multi-set. In relational databases, all attribute collection types are single values. Object relational databases allow you to specify the additional collection types.

Single Value (Column)  The collection type is populated by a single value. A query of a record with a single collection type returns a single value (such as 1, a, or string1).

Set  The collection type is populated by a set of values of the same data type. A query of a record with a set collection type returns a set of values (such as {1, 2, 3, 4}, {a, b, c} or {string1, string2, string3}).

List  The collection type is populated by a list of values of the same data type. A query of a record with a set collection type returns a list of values (such as (3, 2, 1, 4), (b, a, c) or (string2, string1, string3). Order is important here, as opposed to sets and multi-sets, where order is not assumed.

Multi-Set  The collection type is populated by a multi-set of or bag of values of the same data type. A query of a record with a multi-set collection type returns a multi-set or bag of values (such as {1, 1, 2, 3, 3, 3, 3, 4}, {a, b, b, b, c} or {string1, string2, string2, string3}).

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