Scalable Database Server, HiRDB Version 8 Description

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6.10.3 Automatic locking by HiRDB

This section explains the locking of tables and rows that is performed automatically by HiRDB during data updating, addition, and deletion and during data retrieval.

Organization of this subsection
(1) Locking by HiRDB during data updating, addition, and deletion
(2) Locking by HiRDB during data retrieval

(1) Locking by HiRDB during data updating, addition, and deletion

Locking of a table
Referencing, adding, updating, and deletion of the table are allowed by other transactions as well. In other words, the shared update (SU) mode goes into effect.

Locking of a row
The transaction monopolizes the resource and does not allow referencing, adding, updating, or deletion of the row by other transactions. In other words, the exclusive (EX) mode goes into effect.

(2) Locking by HiRDB during data retrieval

Locking of a table
Referencing, adding, updating, and deletion of the table are allowed by other transactions as well. In other words, the shared retrieval (SR) mode goes into effect.

Locking of a row
The transaction monopolizes the resource and allows only referencing of the row by other transactions. In other words, the shared (PR) mode goes into effect.

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