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change <CODE> to <I>.

This commit is contained in:
Bruce Momjian 1998-07-09 17:59:49 +00:00
parent b992bb457d
commit da9db56930
1 changed files with 10 additions and 10 deletions
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20
src/tools/backend/index.html
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@ -25,13 +25,13 @@ HREF="../../include/nodes/parsenodes.h">SelectStmt.</A>
The query is then identified as a <I>Utility</I> query or a more complex
query. A <I>Utility</I> query is processed by a query-specific function
in <A HREF="../../backend/commands"> commands.</A> A complex query, like
<CODE>SELECT, UPDATE,</CODE> and
<CODE>DELETE</CODE> requires much more handling.
<I>SELECT, UPDATE,</I> and
<I>DELETE</I> requires much more handling.
<P>
The parser takes a complex query, and creates a
<A HREF="../../include/nodes/parsenodes.h">Query</A> structure that
contains all the elements used by complex queries. Query.qual holds the
<CODE>WHERE</CODE> clause qualification, which is filled in by
<I>WHERE</I> clause qualification, which is filled in by
<A HREF="../../backend/parser/parse_clause.c">transformWhereClause().</A>
Each table referenced in the query is represented by a <A
HREF="../../include/nodes/parsenodes.h"> RangeTableEntry,</A> and they
@ -39,19 +39,19 @@ are linked together to form the <I>range table</I> of the query, which is
generated by <A HREF="../../backend/parser/parse_clause.c">
makeRangeTable().</A> Query.rtable holds the query's range table.
<P>
Certain queries, like <CODE>SELECT,</CODE> return columns of data. Other
queries, like <CODE>INSERT</CODE> and <CODE>UPDATE,</CODE> specify the columns
Certain queries, like <I>SELECT,</I> return columns of data. Other
queries, like <I>INSERT</I> and <I>UPDATE,</I> specify the columns
modified by the query. These column references are converted to <A
HREF="../../include/nodes/primnodes.h">Resdom</A> entries, which are
linked together to make up the <I>target list</I> of the query. The
target list is stored in Query.targetList, which is generated by
<A HREF="../../backend/parser/parse_target.c">transformTargetList().</A>
<P>
Other query elements, like aggregates(<CODE>SUM()</CODE>), <CODE>GROUP BY,</CODE>
and <CODE>ORDER BY</CODE> are also stored in their own Query fields.
Other query elements, like aggregates(<I>SUM()</I>), <I>GROUP BY,</I>
and <I>ORDER BY</I> are also stored in their own Query fields.
<P>
The next step is for the Query to be modified by any <CODE>VIEWS</CODE> or
<CODE>RULES</CODE> that may apply to the query. This is performed by the <A
The next step is for the Query to be modified by any <I>VIEWS</I> or
<I>RULES</I> that may apply to the query. This is performed by the <A
HREF="../../backend/rewrite">rewrite</A> system.
<P>
The <A HREF="../../backend/optimizer">optimizer</A> takes the Query
@ -60,7 +60,7 @@ HREF="../..//include/nodes/plannodes.h">Plan,</A> which contains the
operations to be performed to execute the query. The <A
HREF="../../backend/optimizer/path">path</A> module determines the best
table join order and join type of each table in the RangeTable, using
Query.qual(<CODE>WHERE</CODE> clause) to consider optimal index usage.
Query.qual(<I>WHERE</I> clause) to consider optimal index usage.
<P>
The Plan is then passed to the <A
HREF="../../backend/executor">executor</A> for execution, and the result