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Scalable Database Server, HiRDB Version 8 Description
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RDAREAs are logical areas in which tables and indexes are stored. Figure 3-1 shows the relationship between an RDAREA, a table, and an index.
Figure 3-1 Relationship between RDAREA, table, and index
![[Figure]](FIGURE/ZU030010.GIF)
The types of RDAREAs are listed in Table 3-1.
Table 3-1 Types of RDAREAs
| No. | RDAREA type | Number that can be created | Required/optional |
|---|---|---|---|
| 1 | Master directory RDAREA | 1 | R |
| 2 | Data dictionary RDAREAs | 1-41 | R |
| 3 | Data directory RDAREA | 1 | R |
| 4 | Data dictionary LOB RDAREAs | 2 | O |
| 5 | User RDAREAs | 1 to 8,388,589 | R |
| 6 | User LOB RDAREAs | 1 to 8,388,325 | O |
| 7 | Registry RDAREA | 1 | O |
| 8 | Registry LOB RDAREA | 1 | O |
| 9 | List RDAREAs | 1 to 8,388,588 | O |
R: Required RDAREA
O: Optional RDAREA
The master directory RDAREA, which is required, stores internal system information.
A data dictionary RDAREA stores dictionary tables and indexes for dictionary tables. Dictionary tables enable users to conduct HiRDB searches. For details about dictionary tables, see the HiRDB Version 8 UAP Development Guide.
There must be at least one data dictionary RDAREA.
The data directory RDAREA, which is required, stores internal system information.
The data dictionary LOB RDAREAs store definition sources and objects for stored procedures and stored functions. When you define a trigger, the data dictionary LOB RDAREA also stores the internally generated SQL object of that trigger. When you use a stored procedure or a stored function, or when you define a trigger, make sure to create a data dictionary LOB RDAREA.
The two data dictionary LOB RDAREAs are:
User RDAREAs, which are required, store tables and indexes. A table can be stored in one or in multiple user RDAREAs. Similarly, a user RDAREA can store one or multiple tables. The same applies to indexes. There are two types of user RDAREAs:
User RDAREAs that can be referenced from all back-end servers are called shared RDAREAs. For details about shared RDAREAs, see the HiRDB Version 8 Installation and Design Guide.
User LOB RDAREAs store long variable-size data, such as documents, images, and audio. A user LOB RDAREA is required in order to use any of the following types of data:
If a table contains multiple types of data (LOB column, BLOB-type attribute in an abstract data type, or plug-in for a plug-in index), each type of data must be stored in a separate user LOB RDAREA. There are two types of user LOB RDAREAs:
The registry RDAREA stores registry information. If plug-ins that use the registry facility are used, it is necessary to create a registry RDAREA. When the registry facility is used, both a registry RDAREA and a registry LOB RDAREA must be created. The registry facility is required in order to use the HiRDB Text Search Plug-in. Some plug-ins do not require the registry facility or a registry RDAREA.
The registry LOB RDAREA stores registry information keys whose key length exceeds 32,000 bytes. If you use plug-ins that use the registry facility, you must create a registry LOB RDAREA. The registry facility is required in order to use the HiRDB Text Search Plug-in. Some plug-ins do not require the registry facility or a registry LOB RDAREA.
A list RDAREA stores lists created by the ASSIGN LIST statement. A list RDAREA is required in order to perform a narrowed search.
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