Re: [HACKERS] adding operators
On Mon, 1 Oct 2007 12:38:07 +1000 Brendan Jurd [EMAIL PROTECTED] wrote: On 10/1/07, Islam Hegazy [EMAIL PROTECTED] wrote: I am a graduate student in the University of Calgary. I want to add some new operators to PostgreSQL to perform some specific tasks in a project I am working in. My problem is that I cannot find my way into the code, where should I start and where to find the documentation for the code. There's no need to hack Postgres to add operators. You can do so by defining functions using CREATE FUNCTION, and then hooking operators up to them using CREATE OPERATOR. And if you need to add C code you can do that too. Check some examples in contrib such as my chkpass module for examples. -- D'Arcy J.M. Cain [EMAIL PROTECTED] | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] adding operators
Thanks for this information. It was really helpful. Another problem that is facing me is altering existing functions. For example, what if I want to change the execution of the SUM function to work as follows: select sum(a) from mytable w(5); which means to sum only 5 records or records that arrived in the last 5 minutes. Do I need to change the core code of PostgreSQL to implement such thing? Regards Islam Hegazy - Original Message - From: Brendan Jurd [EMAIL PROTECTED] To: Islam Hegazy [EMAIL PROTECTED] Cc: pgsql-hackers@postgresql.org Sent: Sunday, September 30, 2007 8:38 PM Subject: Re: [HACKERS] adding operators On 10/1/07, Islam Hegazy [EMAIL PROTECTED] wrote: I am a graduate student in the University of Calgary. I want to add some new operators to PostgreSQL to perform some specific tasks in a project I am working in. My problem is that I cannot find my way into the code, where should I start and where to find the documentation for the code. There's no need to hack Postgres to add operators. You can do so by defining functions using CREATE FUNCTION, and then hooking operators up to them using CREATE OPERATOR. http://www.postgresql.org/docs/8.2/static/xoper.html http://www.postgresql.org/docs/8.2/static/sql-createoperator.html Regards, BJ ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] adding operators
Islam Hegazy wrote: Thanks for this information. It was really helpful. Another problem that is facing me is altering existing functions. For example, what if I want to change the execution of the SUM function to work as follows: select sum(a) from mytable w(5); which means to sum only 5 records or records that arrived in the last 5 minutes. Do I need to change the core code of PostgreSQL to implement such thing? The first can be done with a limit clause, the second using a where clause on a timestamp column - there is no good case that I can see for either usage, not to mention the question of standards compatibility. cheers andrew ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] adding operators
On 10/1/07, Islam Hegazy [EMAIL PROTECTED] wrote: I am a graduate student in the University of Calgary. I want to add some new operators to PostgreSQL to perform some specific tasks in a project I am working in. My problem is that I cannot find my way into the code, where should I start and where to find the documentation for the code. There's no need to hack Postgres to add operators. You can do so by defining functions using CREATE FUNCTION, and then hooking operators up to them using CREATE OPERATOR. http://www.postgresql.org/docs/8.2/static/xoper.html http://www.postgresql.org/docs/8.2/static/sql-createoperator.html Regards, BJ ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
