need help

Started by vamsi krishnaover 20 years ago2 messages
#1vamsi krishna
gvkbtech@yahoo.com

hi,
i want to know how CREATE table (creating a
relation)

works in Postgres.where can i find this in source
code.

also i want to know how postgres parser the
input(create table) and how is this connected to the
create table source code files.

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#2Neil Conway
neilc@samurai.com
In reply to: vamsi krishna (#1)
Re: need help

vamsi krishna wrote:

hi,
i want to know how CREATE table (creating a
relation)

See DefineRelation() in backend/commands/tablecmds.c, and the routines
it calls.

also i want to know how postgres parser the
input(create table) and how is this connected to the
create table source code files.

See the CreateStmt production in backend/parser/gram.y (circa line 1509
in current sources). CREATE TABLE is a utility statement, so a
high-level view of the processing is:

- the query string is scanned (scan.l) and parsed (gram.y), producing a
raw parse tree
- in the analysis phase, transformCreateStmt() does a few simple
transformations of the raw parse tree and produces a Query representing
the CREATE TABLE utility statement
- ProcessUtility() in backend/tcop/utility.c invokes DefineRelation()

-Neil