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SQL

SQL has several sub-languages:
  • meta-data definition language   (e.g. CREATE TABLE)
  • meta-data update language   (e.g. ALTER TABLE)
  • data update language   (e.g. INSERT, UPDATE, DELETE)
  • query language (SQL)   (e.g. SELECT)
Meta-data languages manage the schema.

Data languages manipulate (sets of) tuples.

DBMSs also have a meta-data query language   (e.g. \d)