Types
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Types define an abstract data type or object composed of a collection of similar types of data. For example, create an object type that defines a full address rather than the pieces of an address, such as city, state and postal code. An object type stores the pieces of an address in a single type, storing them in the same location and allowing the full address to be accessed and manipulated as single unit rather than multiple units.
Object types are useful for ensuring uniformity and consistency as they are defined as single encapsulated entity that can be reused in other object types and objects. They also offer flexibility by allowing for the creation of objects that represent real-world situations which is limited in relational objects.
You can choose to create a type that is incomplete, complete, a VARRAY, or a nested table or any combination of the above. An incomplete type specifies no attributes and can be used for circular references such as person - female. It lets the type be referenced before it is complete. The VARRAY type can be used to store small sets of related data. For example, if you have ten offices (each one with a different description) at a particular division in your company, you could create a VARRAY of 10 to hold the details of these offices. The values for a VARRAY type must be fixed and known and small values as they are stored in RAW format. A nested table type can be used when data is repeated for the same entity an unknown number of times and storage is a concern.
Creating and editing
- Note: Objects of this type cannot be created or edited against PostgreSQL datasources.
DBMS platform availability and object actions/operations supported
The table below lists the platforms on which this object type is available. It also lists the object actions available against objects of this type For an introduction to object actions and details on usage of specific actions, see Object actions.
| ORCL | PSTGRS * | |
|---|---|---|
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✓ | ||
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✓ | ||
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✓ |
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✓ |
✓ | |
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✓ |
✓ | |
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✓ |
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✓ | ||
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✓ |