What is Oracle DML?, Introducing Oracle DML
DML (Data Manipulation Language) allows for putting data into a database, retrieval from that
database and removal of data from the database. SQL consists of DDL (Data Definition Language)
and DML (Data Manipulation Language). PL/SQL is a procedural language form of SQL.
- SELECT - retrieves data from the database from the columns of a single table or view or multiple tables or views.
- INSERT - adds rows (tuples) to database tables.
- UPDATE - updates existing rows in database tables.
- DELETE - removes existing rows from database tables.
- TRUNCATE - removes all rows from a table without dropping the table definition. However, no ROLLBACK is allowed when using a TRUNCATE command.
- COMMIT - stores database changes permanently.
- ROLLBACK - removes non-committed database changes completely or back to a specified CHECKPOINT.
- Equi-join - join two or more tables where there are common values in corresponding columns.
- Outside/Outer Join - includes the intersection of two tables plus all elements in one set and not in the other. The table to include its rows not in the other table is indicated using the outer-join operator in the where clause, ie. (+).
- Function - a function acts on a single value or a set of values and returns a single value only.
- The WHERE Clause - constrains the selection of rows retrieved.
- The ORDER BY Clause - reorders the retrieved set of rows after the application of the WHERE clause in ascending or descending order.
- The GROUP BY Clause - groups rows and returns the resulting groups as a set of rows.
- Intrinsic SQL Functions - functions built into Oracle.
- COMMIT and ROLLBACK - COMMIT stores changes to the database and ROLLBACK abandons database changes.
There are a small number of command elements making up DML. These commands are INSERT, UPDATE,
DELETE, SELECT and TRUNCATE. There are many other parts of DML, namely operators, built-in functions,
joins and subqueries.