Relational Database Management Systems, RDBMS

• First principles formulated by E.F. Codd (IBM) in June 1970.
  
  
• All data in tables (2D matrices), having rows and columns.
  
  
• The user does not have to deal with the file structure.
  
  
• All data management involve operations on the tables:
  • Creation of tables.
  • Insert data as rows in tables.
  • Select rows in tables; complex search criteria possible.
  • Update values in rows in tables.
  • Delete rows in tables.
  
  
  
• All this done using the standard(ish) Structure Query Language (SQL).
  
  
• SQL is declarative: What to do, not how.
  
  
• SQL has no control structures (if, when, loops).
  
  
• SQL has specific data types:
  • Integer
  • Floats
  • Char, Varchar
  • Date, time
  • CLOB (characer long object): long strings
  • BLOB (binary long object): large binary blocks of data (e.g. images)
  • A special value NULL to denote the absence of a value.