Buffer Granularity
You can activate table buffering in the Java Dictionary table editor by setting the table buffer attribute and specifying the buffer granularity.
For more information, see Creating Tables .
The granularity is the number of primary key columns that determines the key range of the table to be buffered - that is, the set of rows whose first N key columns have equal values.
To use table buffering, you must have defined one or more primary keys of the table.
You can choose between the following buffering options with respect to buffer granularity:
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Full buffering (N = 0)
The complete table is buffered - that is, the content of the whole table is loaded into the buffer upon first access to any data from the table.
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Generic area buffering (0 < N < # primary key columns)
A generic (buffer) key (first N key fields) is specified. This generic key divides the contents of the table into the generic areas . When accessing any data with a specified generic key, the whole generic area is loaded into the buffer. The figure below shows the case of generic buffering with 1 and 2 fields as generic key.
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Single records buffering (N = # primary key columns)
Single rows are buffered. Only single rows are read from the database and stored in the buffer.
Negative information (nonexistent rows) is also stored for each type of buffer granularity. In the case of full buffering, the buffer stores the whole table and therefore knows which rows do not exist. In the case of buffering generic areas and single rows, this information is stored explicitly: each generic not found area is entered into the buffer and each key of a not found row is buffered explicitly.
