Data Manipulation Language (DML)
A data-manipulation language (DML) is a language that enables users to access or manipulate data, i.e. enable retrieval, insertion, deletion and modification.
Data Manipulation Language
DML is the part of a DBMS interface enabling clients to manage data. Should be
- physically data independent, devoid of any need to mention or understand physical metadata, and can also be
- declarative or non-procedural, devoid of any algorithmic details on how data is manipulated.
Productivity is improved when the DML is non-procedural and more expressive.
Reliability and concurrency issues are addressed by supporting transactions, in particular ACID properties for transactions.
Two types of DMLs:
- (slower..? not really covered in CS348)Procedural DMLs require a user to specify what data are needed and how to get those data.
- Declarative DMLs (also referred to as nonprocedural DMLs) require a user to specify what data are needed without specifying how to get those data.