Study sources
- https://www.youtube.com/watch?v=3J0n7BABEsU
- 비전공자도 쉽게 배워 바로 써먹는 실무 활용 SQL
(Practical SQL that even non-majors can easily learn and use right away) - (to be added)
- Structured Query Language(SQL), initially developed at IBM in 1970s,
- Standard language to communicate with relational Database management systems like : Oracle, MS Access, MS SQL Server, MySQL, DB2, Sybase etc.
- Command based language(not programming language with loops, conditions etc.)
** Query: A database query is a request for a database’s data so we can retrieve or manipulate it.
(Reference: https://www.educative.io/blog/what-is-database-query-sql-nosql)
- Create new Databases
- Create new tables in a Database
- Insert records in a Database
- Update records in a Database
- Delete records in a Database
- Retrieve data from a Database
- Execute queries against a Database
- Set permissions on tables, procedures and views
- Create stored procedures in a Database
- Create views in a Database
- Database developers : Design and deploy Database table structures, forms, reports and queries etc.
- Database administrators(DBA) : Keeping databases up to date and managing database access : Writing reports, documentation and operating manuals
- Database testers : Verify data integrity : Verify data manipulations(Add, update and delete) : Verify data comparisons
- SQL Commands can be classified into groups based on their nature, they are : Data definition language : Data manipulation language : Data control language
: Important commands and operations in data definition language
- Create : To create databases and Database objects
- Alter : To modify existing Database objects
- Drop : To drop Databases and Database objects
- Truncate : To remove all records from a table
- Rename : To rename Database objects
: Important commands and operations in data manipulation language
- Select : To select specific data from a Database
- Insert : To insert new records in a table
- Update : To update existing records
- Delete : To delete existing records from a table
: Important commands and operations in data control language
- Grant : To provide access on the Database objects to the users
- Revoke : To remove user access rights to the Database objects
- Deny : To deny permissions to users
