Database (DBMS) Languages
Filed Under DDL, DML, Data, Databases, Language, Schemas | Posted on August 6, 2009
Once the design of the database is completed and a DBMS is chosen to implement the database, the next step is to define the conceptual and internal schema for the data and any mappings between the two. The languages that are used to do so are : • Data Definition Language (DDL): To specify the [...]
Database System Concepts – Data Model, Schemas and Database state
Filed Under Data, Data Model, Databases, Instance, Model, Schemas, State, Types | Posted on August 4, 2009
A data model is a collection of concepts that can be used to describe the structure of a database. By structure of the database we mean the data types, relationships, and constraints that should hold on the data. Most data models also include a set of basic operations for specifying retrievals and updates on database. [...]
