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

placed in<AHREF="../../include/nodes/parsenodes.h">target list

entries,</I> and 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

<AHREF="../../backend/parser/parse_target.c">transformTargetList().</A>

Other query elements, like aggregates(<I>SUM()</I>),<I>GROUP BY,</I>

table join order and join type of each table in the RangeTable, using

Query.qual(<I>WHERE</I> clause) to consider optimal index usage.

The Plan is then passed to the<A

HREF="../../backend/executor">executor</A> for execution, and the result

returned to the client.

returned to the client. The Plan actually as set of nodes, arranged in

a tree structure with a top-level node, and various sub-nodes as

children.

There are many other modules that support this basic functionality.

They can be accessed by clicking on the flowchart.