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raccourcis clavier

relational model represents database in collection of relations relation simply means a table.

some vocabs

  • tuple - A single row in relation.(a single row of table). Also known as row or record.Row mtlb horizontal wali lines.
  • Attribute- Named Column of relation is attribute. Attribute = column name. they define waht kind of information is stored.
  • Domain- A set of permissible values an attribute can take. Permissible values means values that are allowed.
  • Degree and cardinality- Degree means numbers of attributes(columns) in the relation whereas Cardinality means number of tuples(rows) in the relation.