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SQL Anywhere 10.0.1 » SQL Anywhere Server - SQL Usage » Using Transactions and Isolation Levels » How locking works

How locking works Next Page

Objects that can be locked

To ensure database consistency and to support appropriate isolation levels between transactions, SQL Anywhere uses the following types of locks:

Schema locks provide a mechanism to prevent schema changes from inadvertently affecting executing transactions. Row locks, table locks, and position locks each have a separate purpose, but they do interact. Each lock type prevents a particular set of inconsistencies. Depending on the isolation level you select, the database server uses some or all of these lock types to maintain the degree of consistency you require.

Lock duration

The different classes of locks can be held for different durations: