Overview of Database
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
SQL
- SQL stands for Structured Query Language.
- SQL is a standard language for accessing and manipulating databases.
- Used to Create, Transfer, and Retrieve information from RDBMS.
- RDBMS like MS SQL Server, MS Access, Oracle, MySQL, DB2, Sybase & Informix.
- SQL is defined by ISO & ANSI.
- Simple language
- Very powerful
SQL Commands
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
DDL – Data Definition Language
- These commands are used to create, modify, and drop the structure of database objects.
- CREATE; ALTER, DROP, RENAME, and TRUNCATE commands are used.
DML – Data Manipulation Language
- These commands are used to store, retrieve, modify, and delete the data.
- SELECT, INSERT, UPDATE, DELETE commands are used.
TCL – Transaction Control Language
- These commands are used for managing changes affecting the data.
- COMMIT, ROLLBACK, SAVEPOINT commands are used.
Real-life example
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
We are using it every day in different situations like Food storage, Medical store, clothes cupboard, etc, and are related to the database because the database is like a container.
Food storage
Medical Store
The data is typically organized to model aspects of reality in a way that supports processes requiring information, such as modeling the availability of storage in the kitchen in a way that supports finding what items with quantity details. Like suppose we want to find how much rice is remaining in a rice pot then we can see that pot & find out
- A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
- Suppose our food storage in the kitchen. If we found the rice pot is empty, then we can fill that by simply inserting new rice into a pot. Here we called insert statement, which is a DML statement
- A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
- Suppose we daily use Sugar to make Tea. If we see there is only a little sugar remaining in the pot, then we simply update that sugar with a new one; here, we called the Update statement
- A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
- Some items have manufacturer and expiry dates. If any item expired, then simply put that item into the dustbin; here, we called the delete command
- A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
- In some situations, we use the same name for two different items, but it may conflict, so we need to rename any one item out of that. Suppose we use daily different types of Oil like coconut oil & sunflower oil. Then we can’t give the same name to both, like oil. We have to rename it, and here we simply use Rename command
- A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
Summary
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
This article will help fresher candidates to understand the basics of databases with real-life example
A database is an organized collection of data. It is the collection of schemas, tables, queries, reports, views, and other objects.
Hope so you enjoyed this one.