Logical Database

A Logical Database is a special type of ABAP (Advance Business Application and Programming) that is used to retrieve data from various tables and the data is interrelated to each other. Also, a logical database provides a read-only view of Data.

Structure Of Logical Database:
A Logical database uses only a hierarchical structure of tables i.e. Data is organized in a Tree-like Structure and the data is stored as records that are connected to each other through edges (Links). Logical Database contains Open SQL statements which are used to read data from the database. The logical database reads the program, stores them in the program if required, and passes them line by line to the application program. 

Features of Logical Database:
In this section, let us look at some features of a logical database:

• We can select only that type of Data that we need.
• Data Authentication is done in order to maintain security.
• Logical Database uses hierarchical Structure due to this data integrity is maintained.

Goal Of Logical Database:
The goal of Logical Database is to create well-structured tables that reflect the need of the user. The tables of the Logical database store data in a non-redundant manner and foreign keys will be used in tables so that relationships among tables and entities will be supported.

Tasks Of Logical Database:
Below is some important task of Logical Database:

• With the help of the Logical database, we will read the same data from multiple programs.
• A logical database defines the same user interface for multiple programs.
• Logical Database ensures the Authorization checks for the centralized sensitive database.
• With the help of a Logical Database, Performance is improved. Like in Logical Database we will use joins instead of multiple SELECT statements, which will improve response time and this will increase the Performance of Logical Database.

Data View Of Logical Database:
Logical Database provides a particular view of Logical Database tables. A logical database is appropriately used when the structure of the Database is Large. It is convenient to use flow i.e

• SELECT
• READ
• PROCESS
• DISPLAY

In order to work with databases efficiently. The data of the Logical Database is hierarchical in nature. The tables are linked to each other in a Foreign Key relationship.

Diagrammatically, the Data View of Logical Database is shown as:

Points To Remember:

• Tables must have Foreign Key Relationship.
• A logical Database consists of logically related tables that are arranged in a hierarchical manner used for reading or retrieving Data.
• Logical Database consist of three main elements:
  • Structure of Database
  • Selections of Data from Database
  • Database Program
• If we want to improve the access time on data, then we use VIEWS in Logical Database.

Example: 
Suppose in a University or College, a HOD wants to get information about a specific student. So for that, he firstly retrieves the data about its batch and Branch from a large amount of Data, and he will easily get information about the required Student but didn't alter the information about it.

Advantages Of Logical Database:
Let us look at some advantages of the logical database:

• In a Logical database, we can select meaningful data from a large amount of data.
• Logical Database consists of Central Authorization which checks for Database Accesses is Authenticated or not.
• In this Coding, the part is less required to retrieve data from the database as compared to Other Databases.
• Access performance of reading data from the hierarchical structure of the Database is good.
• Easy to understand user interfaces.
• Logical Database firstly check functions which further check that user input is complete, correct, and plausible.

Disadvantages Of Logical Database:
This section shows the disadvantages of the logical database:

• Logical Database takes more time when the required data is at the last because if that table which is required at the lowest level then firstly all upper-level tables should be read which takes more time and this slows down the performance.
• In Logical Database ENDGET command doesn't exist due to this the code block associated with an event ends with the next event statement.