what is tcl command in sql code example

Example: tcl in sql

SQL language is divided into four types
of primary language statements: DML, DDL, DCL and TCL.
 Using these statements,
we can define the structure of a database by
creating and altering database objects, and we can
manipulate data in a table through
updates or deletions.
 We also can control which user can
read/write data or manage transactions
to create a single unit of work