Technical Settings in Data Dictionary
What are the items in the techical settings for a table in the DD?
The technical settings allows us to
Optimize storage space requirements.
Table access behavior.
Changes to entries logged.
Data class in technical settings
The data class defines the physical area of the database (for ORACLE the TABLESPACE) in which your table is logically stored. If you choose a data class correctly, your table will automatically be assigned to the correct area when it is created on the database.
The most important data classes are (other than the system data):
APPL0 Master data
APPL1 Transaction data
APPL2 Organizational and customizing data
Master data is data which is frequently read, but rarely updated. Transaction data is data which is frequently updated. Organizational und customizing data is data which is defined when the system is initialized and then rarely changed.
There are two more data classes available, USR and USR1. These are reserved for user developments. The tables assigned to these data classes are stored in a tablespace for user developments.
Note:The data class only has an effect on table storage for the database systems ORACLE and INFORMIX.
The size category determines the probable space requirement for a table in the database.
You can select the categories 0 to 4 for your table. Each category is assigned a specific fixed storage area value in the database. When you create a table, initial space is saved for it in the database. If more space is required later as a result of data that has been entered, the storage space is increased in accordance with the category selected.
Press F4 on the field Size category to see the number of data records that can be maintained for the individual categories of your table without complications ensuing. These complications could be for example a reorganization becoming necessary because the maximum space to be reserved for the table was exceeded due to the maintained size category.
The buffering status specifies whether or not a table may be buffered.
This depends on how the table is used, for example on the expected volume of data in the table or on the type of access to a table. (mainly read or mainly write access to the table. In the latter case, for example, one would not select buffering).
You should therefore select
- Buffering not allowed if a table may not be buffered.
- Buffering allowed but not activated if buffering is
principally allowed for a table, but at the moment no buffering
should be active. The
buffering type specified in this case is only
- Buffering allowed if the table should be buffered. In this
case a buffering type
must be specified.