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Diffstat (limited to 'doc/src/sgml/query-ug.sgml')
| -rw-r--r-- | doc/src/sgml/query-ug.sgml | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/doc/src/sgml/query-ug.sgml b/doc/src/sgml/query-ug.sgml index 6d4112ce2bd..2b3a3c56217 100644 --- a/doc/src/sgml/query-ug.sgml +++ b/doc/src/sgml/query-ug.sgml @@ -4,7 +4,8 @@ <Para> <Note> <Para> -This chapter must go into depth on each area of the query language. Currently a copy of the tutorial. +This chapter must go into depth on each area of the query language. +Currently a copy of the tutorial. - thomas 1998-01-12 </Para> </Note> @@ -15,32 +16,38 @@ This chapter must go into depth on each area of the query language. Currently a <Acronym>SQL3</Acronym>. It has many extensions such as an extensible type system, inheritance, functions and production rules. Those are - features carried over from the original <ProductName>Postgres</ProductName> query - language, <ProductName>PostQuel</ProductName>. This section provides an overview - of how to use <ProductName>Postgres</ProductName> <Acronym>SQL</Acronym> to perform simple operations. + features carried over from the original <ProductName>Postgres</ProductName> +query + language, <ProductName>PostQuel</ProductName>. +This section provides an overview + of how to use <ProductName>Postgres</ProductName> <Acronym>SQL</Acronym> + to perform simple operations. This manual is only intended to give you an idea of our flavor of <Acronym>SQL</Acronym> and is in no way a complete tutorial on <Acronym>SQL</Acronym>. Numerous books have been written on <Acronym>SQL</Acronym>. For - instance, consult <Ulink url="refs.html#MELT93">[MELT93]</ULink> or - <Ulink url="refs.html#DATE93">[DATE93]</ULink>. You should also - be aware that some features are not part of the <Acronym>ANSI</Acronym> - standard. + instance, consult <xref linkend="MELT93" endterm="MELT93-full"> or + <xref linkend="DATE97" endterm="DATE97-full">. You should also + be aware that some features of <ProductName>Postgres</ProductName> +are not part of the <Acronym>ANSI</Acronym> standard. </Para> <Sect1> <Title>Concepts</Title> <Para> - The fundamental notion in <ProductName>Postgres</ProductName> is that of a class, + The fundamental notion in <ProductName>Postgres</ProductName> +is that of a class, which is a named collection of object instances. Each instance has the same collection of named attributes, and each attribute is of a specific type. Furthermore, - each instance has a permanent <FirstTerm>object identifier</FirstTerm> (<Acronym>OID</Acronym>) + each instance has a permanent <FirstTerm>object +identifier</FirstTerm> (<Acronym>OID</Acronym>) that is unique throughout the installation. Because <Acronym>SQL</Acronym> syntax refers to tables, we will use the terms <FirstTerm>table</FirstTerm> and <FirstTerm>class</FirstTerm> interchangeably. Likewise, an <Acronym>SQL</Acronym> <FirstTerm>row</FirstTerm> is an - <FirstTerm>instance</FirstTerm> and <Acronym>SQL</Acronym> <FirstTerm>columns</FirstTerm> + <FirstTerm>instance</FirstTerm> and <Acronym>SQL</Acronym> +<FirstTerm>columns</FirstTerm> are <FirstTerm>attributes</FirstTerm>. As previously discussed, classes are grouped into databases, and a collection of databases managed by a |