A description of the overall logical structure of a database expressed in a data definition language (such as the data definition component of SQL).
Second normal form (2NF)
In relational data analysis, a relation is in second normal form if it is in first normal form and every non-key attribute is fully functionally dependent on the primary key – there are no part-key dependencies.
Originally, SQL stood for structured query language. Now, the letters SQL have no meaning attributed to them. SQL is the database language defined in the ISO/IEC 9075 set of international standards, the latest edition of which was published in 2003. The language contains the constructs necessary for data definition, data querying and data manipulation. Most vendors of relational database management systems use a version of SQL that approximates to that specified in the standards.
Data that has enforced composition to specified datatypes and relationships and is managed by technology that allows for querying and reporting.