EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 360+ Courses All in One Bundle
  • Login

DBMS Locks

Home » Data Science » Data Science Tutorials » Database Management Tutorial » DBMS Locks

DBMS Locks

Definition of DBMS Locks

DBMS Locks are referred to as the locking protocols that are implemented in DBMS for the control and regulation of concurrency control, which is a practice to accomplish instantaneous procedures but without disagreeing with each other. In the transaction process, several transactions may appeal for a lock on a data record item concurrently. Therefore, for this, we need a tool for handling the locking requests through the DBMS transactions. This type of mechanism is known to be a Lock manager.

This DBMS Lock depends on the technique of message transitory where the transactions and lock manager interchange messages to control the locking as well as unlocking of the data record items. In this tool, the required data structure used for locking the DBMS transaction process is known to be the Lock table where hashing index is implemented.

Start Your Free Data Science Course

Hadoop, Data Science, Statistics & others

Syntax:

DBMS Locks tool has the following syntax structure for operating in DBMS table data and accessing the table rows and columns as well:

DBMS Locks offers three levels for the lock procedure which are mentioned as:

1. Row Level Locking: The row-level locking is implemented if the clause WHERE calculates to only a single table row.

2. Page Level Locking: In this type of page-level locking, the locking protocol is executed of the clause WHERE assesses to a group of data.

3. Table Level Locking: This type of table locking is applied if the WHERE clause is absent and the query will access the whole table. But when the update is performed by another user the update cannot done for the whole table. Following is the syntax code for the same:

LOCK TABLE <name_of_table> [<name_of_table>]….IN {ROW EXCLUSIVE / ROW SHARE / SHARE UPDATE / EXCLUSIVE / SHARE ROW EXCLUSION / SHARE } [NOWAIT]

How locks work in DBMS?

In DBMS, the locks are tools used for confirming data integrity. In Oracle, the engine locks j table data automatically while running the SQL query commands such as Insert/ Select/ Delete/ Update. This K kind of locking defines implicit locking. In general, the DBMS looks are of two types as follows:

  • Binary Locks
  • Shared & Exclusive Locks

Let us discuss in detail explained below:

Binary Locks: This Binary locks applied on a data item is responsible to deliver two states either locked or unlocked. Here, a distinct lock may be related to every database item suppose X, if the 1 is the value of the lock on X, then the X item will not be accessed when requested by any database operation. Similarly, when the value is 0 on X then, the data item can be accessed on request.

Shared Lock: The shared locks in DBMS are positioned on resources at whatever time a read operation such as the SELECT command is executed. Numerous shared locks can be set on a resource concurrently.

Exclusive Lock: The exclusive locks in DBMS are positioned on resources at whatever time a write operation such as UPDATE/INSERT/DELETE are executed. But we can place only a single exclusive lock on one resource at one time. It means that the initial user who will obtain an exclusive lock will be able to continue to hold the individual proprietorship of the resource, and here, no other operator can obtain the exclusive lock on that resource.

Popular Course in this category
Sale
SQL Training Program (7 Courses, 8+ Projects)7 Online Courses | 8 Hands-on Projects | 73+ Hours | Verifiable Certificate of Completion | Lifetime Access
4.5 (8,900 ratings)
Course Price

View Course

Related Courses
PL SQL Training (4 Courses, 2+ Projects)Oracle Training (14 Courses, 8+ Projects)

Generally, a lock can be defined as a data variable that is related to a data item and the lock indicates that operations can be executed on the data item. Therefore, these DBMS Locks aid to coordinate access to the database record items through concurrent transactions. These entire lock requests are generated to the concurrency control manager and further the transaction will proceed just once when the lock appeal is accepted.

Examples

Let us discuss an example to explain the DBMS Locks illustrated as follows considering the transaction process that occurred taking the database tables. Before proceeding forwards, we will create a details table to practice with the locking of table statements as,

CREATE TABLE details (
id INT NOT NULL AUTO_INCREMENT,
detail VARCHAR(100) NOT NULL,
PRIMARY KEY (id)
);

Output:

DBMS Lock 1

In MySQL, the table can be locked with the below query command that provides the table lock explicitly:

LOCK TABLES name_of_table [WRITE | READ];

The syntax code above identifies the table name that one wants to lock either with type READ or WRITE. Similarly, for unlocking those tables we can release the table as follows:

UNLOCK TABLES;

Let us discuss the READ operation type to show how lock-in DBMS works. For this initiative, we will check the connection id present by the SQL query as,

SELECT CONNECTION_ID();

Output:

DBMS Lock 2

We will then also enter a new record into the table details using the command:

INSERT INTO details(detail) VALUES (‘Testing’);

View the data in the table,

SELECT * FROM details;

Output:

DBMS Lock 3

After this, we will lock the table as,

LOCK TABLE details READ;

Again, try to enter a new record into the table:

INSERT INTO details(detail) VALUES (‘Hello’);

The server will display an error because we can only perform read operations after locking the table with READ lock,

Error Code: 1099. Table ‘details’ was locked with a READ lock and can’t be updated.

Again, if we connect with a different connection using the connection id function running again and inserting a new record then it will show the waiting status since the table was locked in the first session and not released yet. We can view the detailed info as,

SHOW PROCESSLIST;

For this, we will unblock the table from the first session and check the insertion of the next session. Now, it will show proper execution.

For this, the DBMS lock helps to establish concurrency and serializability too.

Advantages and disadvantages

Find some of the listed advantages of the DBMS Locks typed below:

  • DBMS Locks delivers Data integrity for the information stored or accessed from the server.
  • The transactions being performed in any altered manner to confirm serializability and also to escape deadlock.
  • This Lock based protocol is most suitable for read-only type transactions.
  • Here, in this DBMS Locks, all read requests are acknowledged always.
  • This DBMS Locks can be applied to get an improved level of concurrency with a precise low rate of conflict.

In the same way, we can also list out few disadvantages of DBMS Locks mentioned as follows:

  • The protocol DBMS Locks occasionally develops overhead when a transaction setup on a deadline producing rolling back yet again.

Here, the prevention of Deadlock can never be ignored.

We may find a coincidental of transaction starvation because of disagreeing short transactions.

Conclusion

In DBMS, we have various techniques based on protocols followed for the concurrency control that delivers several benefits for controlling the overhead amount which they enforce. DBMS Locks helps to maintain serializability to resolve the conflicts caused among the synchronized transactions. These lock-based protocols provide a mechanism where the transaction cannot write or read the data record unless it attains an applicable lock.

Recommended Articles

This is a guide to DBMS Locks. Here we discuss definition, syntax, and parameters, How locks work in DBMS? examples with code implementation. You may also have a look at the following articles to learn more –

  1. DBMS Components
  2. DBMS Transaction Processing
  3. DBMS_Scheduler
  4. DBMS Multivalued Dependency

All in One Data Science Bundle (360+ Courses, 50+ projects)

360+ Online Courses

50+ projects

1500+ Hours

Verifiable Certificates

Lifetime Access

Learn More

0 Shares
Share
Tweet
Share
Primary Sidebar
Database Management Tutorial
  • DBMS
    • Introduction To DBMS
    • DBMS ER Diagram
    • What is DBMS?
    • DBMS join
    • DBMS Functions
    • Data Administrator in DBMS
    • DBMS Canonical Cover
    • DBMS Log-Based Recovery
    • DBMS Multivalued Dependency
    • Netezza Database
    • DBMS Concepts
    • DBMS Constraints
    • DBMS_Scheduler
    • B+ Tree in DBMS
    • DBMS_LOB
    • dbms entity
    • DBMS Foreign Key
    • DBMS Users
    • DBMS_Metadata.get_ddl
    • Relational Algebra in DBMS
    • DBMS Components
    • DBMS Features
    • DBMS Models
    • DBMS Relational Model
    • Hashing in DBMS
    • DBMS network model
    • Relationship in DBMS
    • ER Model in DBMS
    • Data Models in DBMS
    • Static Hashing in DBMS
    • Advantages of DBMS
    • dbms_output.put_line
    • DBMS Data Dictionary
    • dbms_xplan.display_cursor
    • Normal Forms in DBMS
    • DBMS helps achieve
    • DBMS 3 tier Architecture
    • Relational Calculus in DBMS
    • Serializability in DBMS
    • File Organization in DBMS
    • DBMS Transaction Processing
    • States of Transaction in DBMS
    • Functional Dependency in DBMS
    • Generalization in DBMS
    • Data Independence in DBMS
    • Lock Based Protocols in DBMS
    • Deadlock in DBMS
    • Integrity Constraints in DBMS
    • Concurrency Control in DBMS
    • Validation Based Protocol in DBMS
    • DBMS Locks
    • Normalization in DBMS
    • Transaction Property in DBMS
    • Specialization in DBMS
    • Aggregation in DBMS
    • Types of DBMS
  • DataBase Management
    • Text Data Mining
    • Roles of Database Management System in Industry
    • SQL Server Database Management Tools
    • Database administrator skills
    • Database Management Systems Advantages
    • Database Testing Interview Questions
    • Data Administrator
    • Database Administrator
    • Database Management Software
    • DataStage
    • Types of Database Models
    • Types of Database
    • Hierarchical Database Model
    • Relational Database
    • Relational Database Advantages
    • Operational Database
    • What is RDBMS?
    • What is DB2?
    • Data Masking Tools
    • Database Security
    • Data Replication
    • Bitmap Indexing
    • Second Normal Form
    • Third Normal Form
    • Fourth Normal Form
    • Data Definition Language
    • Data Manipulation Language
    • Data Control Language
    • Transaction Control Language
    • Conceptual Data Model
    • Entity-Relationship Model
    • Relational Database Model
    • Sequential File Organization
    • Checkpoint in DBMS
    • Teradata Create Table
    • Centralized Database
    • Data Storage in Database
    • Thomas write Rule
    • DBA Interview Questions
    • What is JDBC?
    • jdbc hive
    • Apriori Algorithm
    • JDBC Architecture
    • JDBC Interview Questions
    • Wildcard Characters
    • Distributed Database System
    • Multidimensional Database
  • PL/SQL
    • What is PL/SQL?
    • Careers in PL/SQL
    • PLSQL procedure
    • PL/SQL Exception
    • PL/SQL LIKE
    • PL/SQL Raise Exception
    • PLSQL rowtype
    • PLSQL? bind variables
    • PL/SQL Record
    • PL/SQL WITH
    • PL/SQL bulk collect
    • PL/SQL Block Structure
    • PL/SQL else if
    • PL/SQL nvl2
    • PL/SQL Package
    • PL/SQL exists
    • PL/SQL instr
    • PL/SQL listagg
    • PL/ SQL Formatter
    • PLSQLlength
    • PL/SQL Commands
    • PL/SQL Data Types
    • CASE statement in PL/SQL
    • PL/SQL IF Statement
    • Loops in PL/SQL
    • PL/SQL Add Column
    • For Loop in PLSQL
    • PL/SQL Cursor Loop
    • PLSQL Array
    • Cursors in PL/SQL
    • PL/SQL FOR Loop Cursor
    • PL/SQL Queries
    • PL/SQL SELECT INTO
    • PL/SQL TO_CHAR
    • PL/SQL UNION
    • PL/SQL NOT EQUAL
    • PL/SQL varray
    • PL/SQL Concatenate
    • PL/SQL UPDATE
    • PL/SQL TRIM
    • PL/SQL GROUP BY
    • PL/SQL GOTO
    • PL/SQL Date Functions
    • PL/ SQL having
    • PL/SQL to_DATE
    • PL/SQL NVL
    • PLSQL format date
    • PLSQL mod
    • PLSQL round
    • PL/SQL Boolean
    • PL/SQL exit
    • PL/SQL DECODE
    • PL/SQL ROWNUM
    • PLSQL?pivot
    • PLSQL string functions
    • PL/SQL Block
    • PL/SQL Function
    • PL/SQL Unwrapper
    • PL/SQL Table
    • PL/SQL ALTER TABLE
    • PLSQL execute immediate
    • Triggers in PL/SQL
    • PL/SQL Collections
    • PL/SQL stored procedure
    • PL/SQL Anonymous Block
    • PLSQL Interview Questions
  • TSQL Basic
    • TSQL
    • What is T-SQL
    • T-SQL Commands
    • T-SQL String Functions
    • TSQL Interview Questions
  • MariaDB
    • MariaDB Versions
    • MariaDB?list users
    • MariaDB Commands
    • MariaDB odbc
    • MariaDB Workbench
    • MariaDB for windows
    • MariaDB Server
    • MariaDB? Data Types
    • MariaDB?boolean
    • MariaDB phpMyAdmin
    • MariaDB Mysqldump
    • MariaDB Java Connector
    • MariaDB insert
    • MariaDB UPDATE
    • MariaDB? rename column
    • MariaDB AUTO_INCREMENT
    • MariaDB Timezone
    • MariaDB GROUP_CONCAT
    • MariaDB wait_timeout
    • MariaDB MaxScale
    • MariaDB? with
    • MariaDB? create?table
    • MariaDB? SHOW TABLES
    • MariaDB alter table
    • MariaDB List Tables
    • MariaDB JSON Functions
    • MariaDB Foreign Key
    • MariaDB? trigger
    • MariaDB Grant All Privileges
    • MariaDB Select Database
    • MariaDB? create database
    • MariaDB Delete Database
    • MariaDB List Databases
    • MariaDB Functions
    • MariaDB? TIMESTAMP
    • MariaDB create user
    • MariaDB add user
    • MariaDB show users
    • MariaDB Delete User
    • MariaDB? change user password
    • MariaDB? change root password
    • MariaDB reset root password
    • MariaDB IF
    • MariaDB bind-address
    • MariaDB Transaction
    • MariaDB Cluster
    • MariaDB Logs
    • MariaDB Encryption
    • MariaDB? backup
    • MariaDB Replication
    • MariaDB max_allowed_packet
    • MariaDB? performance tuning
    • MariaDB export database
    • MariaDB? import SQL
  • SQLite
    • What is SQLite
    • SQLite Commands
    • SQLite Data Types
    • SQLite COUNT
    • SQLite Boolean
    • SQLite autoincrement
    • SQLite select
    • SQLite? Bulk Insert
    • SQLite? add column
    • SQLite? concat
    • SQLite BETWEEN
    • SQLite group by
    • SQLite CASE
    • SQLite group_concat
    • SQLite array
    • SQLite? enum
    • SQLite sum
    • SQLite create table
    • SQLite Alter Table
    • SQLite Create Database
    • SQLite Delete
    • SQLite connection string
    • SQLite Database
    • SQLite Describe Table
    • SQLite Show Tables
    • SQLite exit
    • SQLite create index
    • SQLite foreign key
    • SQLite Stored Procedures
    • SQLite Extension
  • DB2
    • DB2? current date
    • DB2 purescale
    • DB2 backup
    • DB2 restore
    • DB2 C Express
    • DB2 Version
    • DB2? Architecture
    • DB2? Data Types
    • DB2? load
    • DB2? order by
    • DB2 date
    • DB2 NVL
    • DB2? update
    • DB2 warehouse
    • DB2 grant
    • DB2 database
    • DB2 VARCHAR
    • DB2? INSERT
    • DB2 LISTAGG
    • DB2 LIKE
    • DB2 TRUNCATE TABLE
    • DB2 LIST TABLES
    • DB2 between
    • DB2? current timestamp
    • DB2? length
    • DB2? bind
    • DB2 limit rows
    • DB2? export
    • DB2 with
    • DB2 Create Table
    • DB2 case statement
    • DB2 CAST
    • DB2 Functions
    • DB2 Date Functions
    • DB2? row_number
    • DB2 trim
    • DB2? Translate
    • DB2 UNION
    • DB2 timestamp
    • DB2? TIMESTAMPDIFF
    • DB2? replace
    • DB2 merge
    • DB2 COALESCE
    • DB2 ISNULL
    • DB2? explain
    • DB2 Join
    • DB2 alter column
    • DB2 rename column
    • DB2? Describe Table
    • DB2? rename table
    • DB2 List Databases
    • DB2 LUW
    • DB2 Query
    • DB2 GROUP BY
    • DB2 TO_DATE
    • View Serializability in DBMS
    • MariaDB Join
    • MariaDB JSON
    • MariaDB? show databases
    • Dataset Normalization
    • MariaDB Max Connections
    • jdbc connection
    • MariaDB GUI

Related Courses

SQL Certification Course

PL/SQL Certification Course

Oracle Certification Course

Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Database Management
  • Machine Learning
  • All Tutorials
Certification Courses
  • All Courses
  • Data Science Course - All in One Bundle
  • Machine Learning Course
  • Hadoop Certification Training
  • Cloud Computing Training Course
  • R Programming Course
  • AWS Training Course
  • SAS Training Course

© 2022 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA
Free Data Science Course

Hadoop, Data Science, Statistics & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA
Free Data Science Course

Hadoop, Data Science, Statistics & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more

EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

Special Offer - SQL Certification Course Learn More