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author
Bruce Momjian
Thu, 9 Jul 1998 17:59:49 +0000
(17:59 +0000)
committer
Bruce Momjian
Thu, 9 Jul 1998 17:59:49 +0000
(17:59 +0000)
src/tools/backend/index.html
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diff --git
a/src/tools/backend/index.html
b/src/tools/backend/index.html
index f068e671e43d6df9bbd46f7e806bdc409531703a..6aff709af6d65915eb35904975e80ef112856b3b 100644
(file)
--- a/
src/tools/backend/index.html
+++ b/
src/tools/backend/index.html
@@
-25,13
+25,13
@@
HREF="../../include/nodes/parsenodes.h">SelectStmt.
The query is then identified as a
Utility
query or a more complex
query. A
Utility
query is processed by a query-specific function
in
commands.
A complex query, like
-<
CODE>SELECT, UPDATE,> and
-<
CODE>DELETE> requires much more handling.
+<
I>SELECT, UPDATE,> and
+<
I>DELETE> requires much more handling.
The parser takes a complex query, and creates a
Query
structure that
contains all the elements used by complex queries. Query.qual holds the
-<
CODE>WHERE> clause qualification, which is filled in by
+<
I>WHERE> clause qualification, which is filled in by
transformWhereClause().
Each table referenced in the query is represented by a
HREF="../../include/nodes/parsenodes.h"> RangeTableEntry, and they
@@
-39,19
+39,19
@@
are linked together to form the
range table
of the query, which is
generated by
makeRangeTable(). Query.rtable holds the query's range table.
-Certain queries, like <
CODE>SELECT,> return columns of data. Other
-queries, like <
CODE>INSERT and
UPDATE,
> specify the columns
+Certain queries, like <
I>SELECT,> return columns of data. Other
+queries, like <
I>INSERT and
UPDATE,
> specify the columns
modified by the query. These column references are converted to
HREF="../../include/nodes/primnodes.h">Resdom entries, which are
linked together to make up the
target list
of the query. The
target list is stored in Query.targetList, which is generated by
transformTargetList().
-Other query elements, like aggregates(<
CODE>SUM()),
GROUP BY,
>
-and <
CODE>ORDER BY> are also stored in their own Query fields.
+Other query elements, like aggregates(<
I>SUM()),
GROUP BY,
>
+and <
I>ORDER BY> are also stored in their own Query fields.
-The next step is for the Query to be modified by any <
CODE>VIEWS> or
-<
CODE>RULES> that may apply to the query. This is performed by the
+The next step is for the Query to be modified by any <
I>VIEWS> or
+<
I>RULES> that may apply to the query. This is performed by the
HREF="../../backend/rewrite">rewrite system.
The
optimizer
takes the Query
@@
-60,7
+60,7
@@
HREF="../..//include/nodes/plannodes.h">Plan, which contains the
operations to be performed to execute the query. The
HREF="../../backend/optimizer/path">path module determines the best
table join order and join type of each table in the RangeTable, using
-Query.qual(<
CODE>WHERE> clause) to consider optimal index usage.
+Query.qual(<
I>WHERE> clause) to consider optimal index usage.
The Plan is then passed to the
HREF="../../backend/executor">executor for execution, and the result