Data Storage and Querying in DBMS
Database Management System is the collection of interrelated data/information or set of programs that manages, control and access the use of data. Through DBMS, It is possible for the users to manage the data efficiently in a database in order to increase accessibility and productivity. For example – Employee’s record , Telephone Book having all the different contacts saved at a single place very efficiently.
So, Database System is basically a software system, having an organized collection of structured information, stored in a computer system. It enables the user to create, maintain, define and control access to the database.
Uses of DBMS:
- For increasing the productivity through real-time component data.
- For Reducing the data redundancy and inconsistency.
- For Enhancing the data integrity.
- For Retrieving the data.
- For Data Security.
- For Data Indexing.
For more details, you can read the article Application of DBMS.
The Database System is further divided into two components. They are as follows:
- Data Storage Manager
- Query Manager
Data Storage Manager:
Data Storage Manager also known as “Database Control System”, is generally a program that provides an interface between the data/information stored and the queries received. It helps us to maintain the integrity and consistency of the database by applying the constraints. It is a highly flexible and scalable product that provides us with the capability of fully managed storage.
Storage Manager is generally in charge of the interactions with the File Manager, where raw data is stored on the data with the help of the file system. It translates various DML statements into low-level commands.
- Authorization and Integrity Manager: The main purpose of the Authorization and Integrity Manager is to ensure the satisfaction of the integrity constraints and checks the authority of users to access information.
- Transaction Manager: The main purpose of Transaction Manager is to ensure that even after the system failures, the database should remain in a uniform state.
- File Manager: The main purpose of File Manager is to manage the allocation of space on the disk storage.
- Buffer Manager: The main purpose of Buffer Manager is to fetch the data from disk storage into the main memory.
Query Processor contains the following three components:
- DDL Interpreter: DDL Interpreter is the Data Definition Language Interpreter which is basically used to build and modify the structure of your tables and other objects in the table.
- DML Compiler: DML Compiler is the Data Manipulation Language which is used for adding (inserting), deleting, and modifying (updating) data in a database. or we can say translating the DML statements into query language consists of low-level instructions that only query engine can understand.
- Query Evaluation Engine: It basically executes the low-level language instructions, generated by DML Compiler.