What İs SQL?
Structured Query Language, meaning sql, is not a programming language. Also known as a sublanguage, it is used for database operations. The raw information transferred to the computer is called data. Anything stored by a computer is called data.
It lists the data by querying within the criteria we set. With this system, which is a query language, it has become easier to operate on data. In other words, SQL is a database management system and only works in the database.
Past to Present Database
Databases emerged in the early 1960s and have undergone radical evolutionary processes over time.
These early systems were simple and flexible. Relational databases became more popular in the 1980s, followed by object-oriented databases in the 1990s.
Later, NoSQL emerged in response to the growth of the internet and the need for faster processing of unstructured data.
After the evolution of databases from the past, finally, cloud databases and autonomous databases are revolutionizing data collection, storage, management and use.
What are the Advantages of Using SQL?
With SQL, you can categorize information, organize clutter, and access data quickly.
In short, SQL database:
- Creating a databas
- Creating a table
- Add data
- Querying data
- To receive data regularly
- Reading data
- Update data,
- Delete data,
- Ensuring data security
It is a query language used for.
SQL Commands
There are some commands used to perform SQL operations. We can sort it like this:
SQL – Data Query Language:
It is the command used to pull data from SQL database. The SQL command is selected.
DDL – Data Definition Language:
It is used as Data Description Language (DDL). This means creating a database, characterizing its structure, being able to use it, and destroying it when you’re done. DDL deals with the description part of the database schema. It is used to create and change the structure of objects in the database. Therefore, SQL commands; It is create, drop, alter, truncate, comment, rename.
DML – Data Manipulation Language
It means Data Manipulation Language, that is, it is used to store, change, delete and update data in the database. A few of the DML commands are insert, update, delete and merge.
DCL – Data Control Language SQL:
It is brought as a Data Control Language that enables you to secure your database against abuse. It is used to grant and remove schema objects access to some users. A few of the DCL commands are grant and revoke.
TCL – Transaction Control Language:
It is also called “Database Transaction Management”. Transaction management means maintaining the transaction, i.e. controlling the ground rules for the ACID properties of the database. The operation has only two consequences; positive or negative. SQL commands are transaction, commit, rollback, savepoint. TCL is used to manage changes made by DML. In short, changes made by DML commands can be controlled by DCL.
