SQL PROGRAMMING STYLE- P6 pdf
SQL PROGRAMMING STYLE- P6 pdf
... the count is redundant; SQL is orthogonal, and the scalar subquery can be used wherever the scalar variable is used. Rows are not records and columns are not fields. SQL is a declarative language, ... TIMESTAMP,—null means current CHECK(in_time < out_time), PRIMARY KEY (user_id, in_time)); Many new SQL programmers are scared of NULLs, but this is a good use of them. We do not...
Ngày tải lên: 06/07/2014, 23:20
SQL PROGRAMMING STYLE- P4 pdf
... about Student Programming Practices,” Structured Programming , Fall 1989, p. 215. Celko, J. SQL for Smarties (3rd ed.). San Francisco: Morgan-Kaufmann, 2005. Celko, J. SQL Puzzles ... of Programming Style . Boston: McGraw-Hill, 1982. Ledgard, H. Programming Prover bs. Rochelle Park, NJ, Hayden Books, 1975. Ledgard, H., and L. J. Chmura. Fortran with Style:...
Ngày tải lên: 06/07/2014, 23:20
SQL PROGRAMMING STYLE- P9 pdf
... tell what is good and what is bad in SQL. The procedural programmers had a deterministic environment in which the same program ran the same way every time. SQL decides how to execute a query ... front did not know this. Would you like to pick which four children will die because of sloppy programming? See what we mean by the last sentence in Ledgard’s quote? 9.6.2 Save Your First ....
Ngày tải lên: 06/07/2014, 23:20
SQL PROGRAMMING STYLE- P14 pdf
... revolution and have reverted back to ad hoc programming but call it “extreme” or “agile” these days to make sloppy programming sound better. In classic structured programming, you have three control ... do, and it is why SQL is also known as a functional language. Procedural, communicational, informational, and functional cohesion are a bit more complicated in SQL than in 3GL pro...
Ngày tải lên: 06/07/2014, 23:20
SQL PROGRAMMING STYLE- P16 pdf
... <table name > [BEFORE | AFTER | INSTEAD OF] [INSERT| DELETE | UPDATE] AS [< ;sql stmt> | BEGIN ATOMIC {< ;sql stmt>;} END] For obvious reasons, only one INSTEAD OF trigger per INSERT, ... Mullins calls catalog clutter . For example, in DB2, every unnecessary VIEW that is created in SQL will potentially insert rows into four VIEW-specific schema information table...
Ngày tải lên: 06/07/2014, 23:20