transaction in dbms - Wikitechy

What is Transaction in DBMS ?

webmaster — Wed, 26 Oct 2022 10:07:01 +0000

If we need one or more database access operations, we have a logical unit of processing called Database Transaction.
In simple, database transactions represent real-world events of any enterprise.
Database is inconsistent during the transaction.
Database is committed only once the state is changed from one consistent state to another.

State of Transactions

Active State

A transaction is said to be in an active state when the execution process begins.
This is the state where read write operations are performed.

Partially Committed

A Transaction is said to be in a partially committed state after the end of a transaction.

Committed State

When a transaction is executed successfully, transaction is said to be in the committed state.
Changes made are recorded in the database permanently.

Failed State

A transaction is considered to be in the failed state when any one of the checks fails, or when the transaction is aborted while it is in the active state.

Terminated State

A transaction is said to be in the terminated state when certain transactions which are leaving the system cannot be restarted.

What is the concept of ACID properties in DBMS ?

webmaster — Fri, 03 Jun 2022 09:41:49 +0000

ACID stands for Atomicity, Consisency, Isolation, and Durbility property. Multiple users can share data in a safe and secure way using these properties.

Atomicity:

Atomicity is based on the principle of “either all or nothing” which means that if any updates happens inside the database then that updates should be available for others beyond user and application.
If any updates happens inside the database then that updates should not be available for others beyond user and application.

Consistency:

Inside a database before or after any transaction takes place this ensures that consistency is maintained.

Isolation:

This property states that happens in isolation with other which means that any transactions that has started but not yet completed should be in isolation with others so that the other transactions are not affected by this transaction.

Durability:

This property states that the data should always be in a durable state i.e. any data which is in the committed state should be available in the same state even if any failure or restart occurs in the system

Transaction States in DBMS

Characteristics of DBMS ?

Editor — Mon, 19 Jul 2021 10:29:18 +0000

Characteristics of DBMS ?

D) all the above

Answer : D) all the above

What is DBMS ?

A database management system (DBMS) is a software package designed to define manipulate, retrieve and manage data in a database.
A DBMS mostly manipulates the data itself, the data format, field names, record structure and file structure. It also defines rules to validate and manipulate this data.
A DBMS relieves users of framing programs for data maintenance. Fourth-generation query languages, such as SQL, are used along with the DBMS package to interact with a database.
Some other DBMS examples include:
- MySQL
- SQL Server
- Oracle
- dBASE
- FoxPro

Characterstics of DBMS

Data abstraction and independence.
Data security.
A locking mechanism for concurrent access.
An efficient handler to balance the needs of multiple applications using the same data.
The ability to swiftly recover from crashes and errors, including restartability and recoverability.
Robust data integrity capabilities.
Logging and auditing of activity.
Simple access using a standard application programming interface (API).
Uniform administration procedures for data.

Characteristics of DBMS

Advandages of DBMS

One of the most advantages of using a DBMS is that it lets end users and application programmers access and use the same data while managing data integrity.
Data is better protected and maintained when it can be shared using a DBMS instead of creating new iterations of the same data stored in new files for every new application.