Re: [HACKERS] "DML"
От | Don Baccus |
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Тема | Re: [HACKERS] "DML" |
Дата | |
Msg-id | 3.0.1.32.19990611112841.0077f1bc@mail.pacifier.com обсуждение исходный текст |
Ответ на | Re: [HACKERS] "DML" (Don Baccus <dhogaza@pacifier.com>) |
Ответы |
Re: [HACKERS] "DML"
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Список | pgsql-hackers |
At 01:12 PM 6/11/99 -0400, Thomas Good wrote: >I dunno about that one Don. DML and its cousins (DDL and DCL) are >very much in common usage these days. DDL (Data Definintion Language) >would be CREATE TABLE and so on whilst DML is INSERT INTO, UPDATE >and DELETE FROM...DCL (Data Control Language) usually deals with >permissions (GRANT/REVOKE) and often gets lumped in with DDL. >If you have a look at any comprehensive text that tells neophytes >(like yers truly) how to get a handle on SQL... Hmmm...it appears "The Practical SQL Handbook" gets it wrong, then, as it lumps "select" with data modification statements when it makes its breakdown between DML, data definition, and what they call data administration (clearly they mean the same things as your DCL definition, i.e. grant/revoke type stuff). And the AOLServer guys get it right as they talk about "ns_db dml" working on insert/update/delete and "also data definition" statements, i.e. they recognize the difference in their documentation. OK, in the DML, DCL, and DDL decomposition of things, just what *is* a select statement? You've given a simple definition of the decomposition, why not bottle it and pour it into the docs? ... >PROGRESS, for example, does not support DCL at all. One must use >the `data dictionary', an awkward user interface. Barf > It claims to >support DDL but you can't access the tables you make with DDL cmds >via the dictionary. And Codds hasn't struck them dead with lightning? :) - Don Baccus, Portland OR <dhogaza@pacifier.com> Nature photos, on-line guides, and other goodies at http://donb.photo.net
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