Mind blowing SEO improving and Google rank increasing Signature Rotator SEO Tool.

Thread: 

What is a Database Lock ?

Ads
banner
banner
rahhulkumar1 Offline referral

Posts: 53
Joined: Oct 2015
Reputation: 1

#1
Member
What is a Database Lock ?
marcus_avrelius Offline referral

Posts: 2,519
Joined: May 2013
Reputation: 102

#2
Support Team
If you have more than one user submitting data to SQL lock is used.
harishsharma Offline referral

Posts: 133
Joined: Jun 2016
Reputation: 0

#3
Member
A database lock is used to “lock” some information in a database so that only one database user may replace that specific data. So, database locks occur to prevent two or more database users from updating the same exact piece of details at the same exact time. When data is locked, then that means that another database session can NOT update that data until the lock is released.
praveenk Offline referral

Posts: 23
Joined: Mar 2016
Reputation: 0

#4
Junior Member
Too many database lock causes server load issue, so always optimize database queries to improve server performance
chandlerbong Offline referral

Posts: 7
Joined: Jun 2017
Reputation: 0

#5
Junior Member
In database, a lock is used to access a database concurrently for multiple users. This prevents data from being corrupted or invalidated when multiple users try to write to the database. Any single user can only modify those database records (that is, items in the database) to which they have applied a lock that gives them exclusive access to the record until the lock is released.
From the programmer's point of view, there are two mechanisms for locking data in a database:
Pessimistic locking is where a record or page is locked immediately when the lock is requested.
Optimistic locking is where a record or page is only locked when the changes made to that record are updated.
The Optimistic locking situation is only appropriate when there is less chance of someone needing to access the record while it is locked; otherwise it cannot be certain that the update will succeed because the attempt to update the record will fail if another user updates the record first. With pessimistic locking it is guaranteed that the record will be updated.
In the sight of database, there are three mechanisms for locking data in a database:
Exclusive Locking: The resources have been locked only allow accessing the locking operation, other operations will not be accepted. Implementing the command of update data, that is, INSERT, UPDATE or DELETE command, SQL Server will use an exclusive lock automatically. However, when the object has other locks, we cannot use exclusive lock. Exclusive lock can be released until the end of transaction.
Shared locking: The resources which have been locked only allow other users reading, but not modifying. In SELECT command, SQL Server usually locked the object with shared lock. Usually when the data with the shared lock has been read, the shared lock would be released immediately.
Update locking: Update lock is created to avoid deadlock. When SQL Server updates the data, it will lock the data with update lock firstly, and the data can be read, but cannot be modified. When SQL Server sure to update operation of data, it will change to exclusive lock automatically. However, there are other locks in object, it cannot be locked with updated lock.
seo users Offline referral

Posts: 11
Joined: Jul 2017
Reputation: 0

#6
Junior Member
It is used to “lock” some information in a database so that only one database user may replace that specific data
I am a SEO USERS .
John Alex Offline referral

Posts: 10
Joined: Jul 2017
Reputation: 0

#7
Junior Member
A lock key is the thing that identifies what is being locked. Sometimes it identifies a page, sometimes a row, sometimes a table etc.

Most often it is a page, and probably contains some identification of what file is in question, and then offset into the file, either as a page number or byte offset in the file.
anirban09p Offline referral

Posts: 151
Joined: Apr 2015
Reputation: 1

#8
Member
Database locking is a varied, evolving, complicated, and technical topic. As testers, we often think that it belongs in the realm of the developer and the DBA (i.e. not my problem). But to both functional and performance testers, it is the enemy and has led to many disasters (as the presenter can personally attest).
damponting44 Offline referral

Posts: 492
Joined: Oct 2016
Reputation: 0

#9
Senior Member
Locking the exchange does this by asking for a bolt on the bit of information. Locks have distinctive modes, for example, shared or restrictive.





User(s) browsing this thread: 1 Guest(s)