Database Management: Recovery, Concurrency, and More

Database Management Essentials

Data Recovery

Recovery: Recover data from the sources of error mentioned above. Restoring the database to its normal state is the responsibility of the DBA, who is responsible for implementing the procedures for error detection and recovery.

The DBA is the one with the centralized control of the database. This reduces the number of people who have access to technical and design details for the operation of DBMS.

Concurrency Control

Concurrency: It occurs in a multi-user environment when multiple users try to access the same data object at the same time.

Concurrency occurs when the system is multi-user and does not make adequate controls to synchronize the processes that affect the database. This is commonly referred to as little or no effectiveness of lockout.

Data Granularity

Granularity is the size of the insured units. For example, granularity can protect a field, record, etc.

Deadlock

Deadlock is a technique that avoids concurrency errors. It occurs when we develop a circular wait between two transactions, and each of these requests an update on the same file. It prevents other users from accessing the resource until the end of the process, resulting in the expected circular wait.

Database Outline

Outline: Create the original database schema and generate the data dictionary through DDL propositions.

Storage Structures

Storage structures: Responsible for generating selected secondary structures for the environment and defining the methods of access to information, the latter by means of propositions in DML.

Change Layout and Organization

Change layout and organization: Redesigning the layout of the database is a rare activity. This would be necessary before an abrupt change of the original conditions that gave rise to the primary schema design. Proposals to carry out this task are performed in DDL.

Grant Access Permissions

Grant access permissions: Responsible for registering users to allow access to the DBMS. Assign each a number of attributes that allow you to enjoy privileges such as access to certain areas of application, data, or use of system resources.

Specifying Integrity Constraints

Specifying integrity constraints: Create a series of tables which specify the set of restrictions that will apply during the upgrade process.

Data Backup

Backup: Log files (transaction log)

Daily transactions are recorded in the database. When a problem occurs, we turn to the log files, which are reversible and can also retrieve the last transaction that was made.