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What does locking mean in database?
Record locking is the technique of preventing simultaneous access to data in a database, to prevent inconsistent results. The classic example is demonstrated by two bank clerks attempting to update the same bank account for two different transactions.
What are locking protocols How are they useful?
Two Phase Locking Protocol also known as 2PL protocol is a method of concurrency control in DBMS that ensures serializability by applying a lock to the transaction data which blocks other transactions to access the same data simultaneously. Two Phase Locking protocol helps to eliminate the concurrency problem in DBMS.
Why is transaction locking important in SQL Server?
As the number of users that access the data increases, it becomes important to have applications that use transactions efficiently.
What are transaction locking and row versioning mechanisms?
This guide describes the locking and row versioning mechanisms the SQL Server Database Engine uses to ensure the physical integrity of each transaction and provides information on how applications can control transactions efficiently. Applies to: SQL Server 2005 (9.x) through SQL Server 2017, unless noted otherwise.
What’s the difference between concurrency between transactions and locks?
The common part across all RMDS as far as I can tell is that concurrency between transactions is defined by isolation level whereas concurrency between locks is controlled by lock types (shared, exclusive, etc). To summarize, locks are low level mechanism to control consistency of objects and concurrency .
How does database blocking and deadlocks work in SQL Server?
Database Blocking and Deadlocks Database blocking occurs when a connection to the SQL server locks one or more records, and a second connection to the SQL server requires a conflicting lock type on the record, or records, locked by the first connection. This results in the second connection waiting until the first connection releases its locks.