DB glossary

1
DB glossary

• (focus on typical SQL RDBMS, not XQuery or
  SPARQL)

2
facts are rows in tables

• Tables have columns of some type, giving each row
  a number of fields (i.e. n-ary)

3
query

• a declarative specification of a result set of
  rows in terms of base tables, views, and
  rowset-oriented operators such as select,
  project, join, and union
• uses SQL SELECT..FROM...WHERE...GROUP
  BY...HAVING...UNION...
• Queries can be optimized using algebraic rewrite
  rules.
• closure - the input and output of a query is a
  set of rows.

4
View

• a named, stored, secured, and often updateable
  query.
• Some DBs support recursive views or some kind of
  transitive closure operator.

5
integrity constraints

• conditions about data that must hold at
  transaction boundaries.
• conditions are declarative and can be about data
  in a column, e.g.
• cannot be null,
• must be unique,
• must be one of a defined set of values.
• Or can relate 2 or more columns, e.g. referential
  integrity requires that a foreign key must refer
  to a primary key

6
Triggers

• one of the first examples of an ECA rule
• A trigger fires when a row or set of rows is
  inserted, deleted, or updated in a table.
• The trigger may perform arbitrary database
  modifications in the scope of the triggering
  transaction.

7
how to evolve the knowledge base

• insert, update, delete
• Transaction

8
role based access control

• How to secure the data (facts)