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Mentor Deck - SQL.pptx
- 4. MENTOR SESSION
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An RDBMS or Relational Database Management System is a DBMS which is specifically designed
for relational datasets. It is intended for structured data format. Data in an RDBMS is stored in
Tables. A Table consists of Rows and Columns where rows contain the actual data or
observations, columns are the labels of the same. One can think an RDBMS tables it as a
spreadsheet in excel.
What is RDBMS?
- 5. MENTOR SESSION
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In most of the real-life scenarios, the data we generate from various operations and business
processes are structured and can be stored in two-dimensional tables. From late 20th century,
RBDMS has been widely accepted by most of the businesses and has become an essential tool to
store, use and report data & information. Here are some of the important aspects on why do we
need RBDMS –
1. Easy to use. An RDBMS table gives an intuition on how we use excel spreadsheets. It is easy to
store and use the data.
2. Cost-effectiveness & efficiency. Most of the traditional RBMDS systems are cost-effective and vast
amount of data can be stored with relatively much lower cost and higher efficiency.
3. Can be queried by Structured Query Language which is easy to learn and apply to extract
information.
4. One can design an entity-relationship model in RDBMS to store the data in a more structured format
which eventually helps in querying effectively and extract insights.
5. It helps to maintain the integrity and consistency of the data stored.
Why do we need RDBMS?
- 7. MENTOR SESSION
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Structured Query Language(SQL) is a 5th generation programming language which is used to
write queries on RDBMS systems to manage and extract data and tables. It is extremely useful to
handle structured data.
SQL is a user-friendly programming language which is easy to understand and English like
language and could be used to effectively query from the databases.
What is SQL and Why do we need it?
- 8. MENTOR SESSION
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While we start querying on databases, here are few key concepts on SQL –
1. DDL – Data Definition Language, used to create tables and other database objects. Few important
commands are CREATE, ALTER, DROP, TRUNCATE, RENAME etc.
2. DML – Data Manipulation Language, used to insert, update or delete records from database tables.
Few important commands are INSERT, UPDATE, DELETE etc.
3. DCL – Data Control Language, used for access controlling the database environment. Important
commands are GRANT, REVOKE etc.
4. DQL – Data Query Language, used to query the data and extract results. SELECT is the DQL
command.
5. TCL – Transaction Control Language, used to deal with the transactions within the database. It
helps controlling the transaction level events in the database. Important commands are COMMIT,
ROLLBACK etc.
Key concepts of SQL
