Re: [GENERAL] Proper entry of polygon type data
Hi Brent, I am aware of PostGIS and already use it. My question was regarding the entry format of PostgreSQL polygon data. There is a void in the PostgreSQL documentation regarding this. Incidentally, PostGIS uses PostgreSQL polygon, point, and path data types. Using PostGIS for simple , non-geographic, polygon rules is a bit like using a tank to kill a mosquito. Peter Brent Wood wrote: Hi Peter, If you want to use Postgres to store/manage/query spatial data, I strongly recommend you look at PostGIS, not the native Postgres geometry types. Brent Wood Brent Wood DBA/GIS consultant NIWA, Wellington New Zealand Peter Willis pet...@borstad.com 03/24/09 10:35 AM Hello, I would like to use 'polygon' type data and am wondering about the entry format of the vertex coordinates. Are the coordinates of the polygon type to be entered one entry per polygon vertex, or one entry per polygon edge segment? For example: I have a triangle with vertex corners A, B, C. One entry per vertex format suggests INSERT INTO my_table (my_polygon_column) VALUES ( ((Ax,Ay),(Bx,By),(Cx,Cy)) ); One entry per edge format suggests INSERT INTO my_table (my_polygon_column) VALUES ( ((Ax,Ay),(Bx,By),(Bx,By),(Cx,Cy),(Cx,Cy),(Ax,Ay)) ); Which entry format is the correct one? If per vertex format is the correct one, do I need to 'close' the path by entering the first vertex again at the end of the list? ie: INSERT INTO my_table (my_polygon_column) VALUES ( ((Ax,Ay),(Bx,By),(Cx,Cy),(Ax,Ay)) ); Thanks, Peter -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] Proper entry of polygon type data
Mark Cave-Ayland wrote: Peter Willis wrote: Incidentally, PostGIS uses PostgreSQL polygon, point, and path data types. Errr... no it doesn't. PostGIS uses its own internal types to represent all the different geometries, although it does provide a cast between the existing PostgreSQL types as an aid for people wishing to migrate. I stand corrected I guess. The last time I looked at the actual guts of PostGIS was WY back. And that was long before I actually started using it. ...of course, my WAAA back memory may be crossed with my WAAAY back forgetfulness, there as well Peter -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
[GENERAL] Proper entry of polygon type data
Hello, I would like to use 'polygon' type data and am wondering about the entry format of the vertex coordinates. Are the coordinates of the polygon type to be entered one entry per polygon vertex, or one entry per polygon edge segment? For example: I have a triangle with vertex corners A, B, C. One entry per vertex format suggests INSERT INTO my_table (my_polygon_column) VALUES ( ((Ax,Ay),(Bx,By),(Cx,Cy)) ); One entry per edge format suggests INSERT INTO my_table (my_polygon_column) VALUES ( ((Ax,Ay),(Bx,By),(Bx,By),(Cx,Cy),(Cx,Cy),(Ax,Ay)) ); Which entry format is the correct one? If per vertex format is the correct one, do I need to 'close' the path by entering the first vertex again at the end of the list? ie: INSERT INTO my_table (my_polygon_column) VALUES ( ((Ax,Ay),(Bx,By),(Cx,Cy),(Ax,Ay)) ); Thanks, Peter -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] Question about accessing current row data inside trigger
Hello, This issue is resolved. I was using the wrong struct. Peter Tom Lane wrote: peter Willis [EMAIL PROTECTED] writes: I have a trigger function written in C. ... Since the trigger is called after each row update the actual row data should be available in some way to the trigger. Sure: tg_trigtuple or tg_newtuple depending on which state you want. See http://www.postgresql.org/docs/8.0/static/trigger-interface.html regards, tom lane ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [GENERAL] Question about accessing current row data inside trigger
Hello, I resolved this issue already. The trigger now works fine. I was looking at the wrong structure. Thanks, Peter Michael Fuhr wrote: On Tue, Mar 08, 2005 at 11:37:14AM -0800, peter Willis wrote: I have a trigger function written in C. The trigger function is called via: CREATE TRIGGER after_update AFTER UPDATE ON some_table FOR EACH ROW EXECUTE PROCEDURE my_trigger_function(); Since the trigger is called after each row update the actual row data should be available in some way to the trigger. What functionality (SPI ?) do I use to use the column values from the current row in the actual trigger? See Writing Trigger Functions in C and C-Language Functions in the documentation. Here are links to documentation for the latest version of PostgreSQL: http://www.postgresql.org/docs/8.0/interactive/trigger-interface.html http://www.postgresql.org/docs/8.0/interactive/xfunc-c.html ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[GENERAL] Question about accessing current row data inside trigger
Hello, I have a trigger function written in C. The trigger function is called via: CREATE TRIGGER after_update AFTER UPDATE ON some_table FOR EACH ROW EXECUTE PROCEDURE my_trigger_function(); Since the trigger is called after each row update the actual row data should be available in some way to the trigger. What functionality (SPI ?) do I use to use the column values from the current row in the actual trigger? thanks for any insight, Peter ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
[GENERAL] How do I recover from pg_xlog/0000000000000000 (log file 0, segment 0) failed: No such file or directory
Hello, Is there a way to recover from the following error? I have (had) an existing database and wish not to lose the data tables. Thanks for any help, Pete [EMAIL PROTECTED] /]$ pg_ctl start postmaster successfully started [EMAIL PROTECTED] /]$ LOG: database system shutdown was interrupted at 2004-10-18 11:41:55 PDT LOG: open of /web2-disk1/grip/database/pg_xlog/ (log file 0, segment 0) failed: No such file or directory LOG: invalid primary checkpoint record LOG: open of /web2-disk1/grip/database/pg_xlog/ (log file 0, segment 0) failed: No such file or directory LOG: invalid secondary checkpoint record PANIC: unable to locate a valid checkpoint record LOG: startup process (pid 2803) was terminated by signal 6 LOG: aborting startup due to startup process failure [EMAIL PROTECTED] /]$ ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
