Fundamentals

Data Retrieval Language the commands used to select data from the database
SELECT
Data Definition Language(DDL)statements are used to define the database structure or schema
o Create -to create objects in database
o ALTER - alters the structure of the database
o Drop -drop objects from database
o Truncate -remove all record from table,including all spaces allocated for the records removed
o Comments -add comments to the data dictionary
o Rename -rename an object
o Describe -Meta data of the table

Data Manipulation Language(DML)statements are used for managing data within schema object
o Insert - insert data into the table
o Update -update existing data within a table
o Delete -delete all records from a table.the space for the records remain
o Merge -Upsert operation(insert or update)
o Call -call a pl/sql or java subprogram
o Explain plan -Explain access path to data
o Lock table -control concurrency
Data Control Language (DCL) statements. Some examples:
o GRANT - gives user's access privileges to database
o REVOKE - withdraw access privileges given with the GRANT command
Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.
o COMMIT - save work done
o SAVEPOINT - identify a point in a transaction to which you can later roll back
o ROLLBACK - restore database to original since the last COMMIT
o SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use