[SQL] Replacing a table with constraints
I have a table called Counties which partially contains a lot bad data. By" bad data", I mean some records are missing; some exist and shouldn't; and some records have fields with erroneous information. However, the majority of the data in the table is accurate. I have built/loaded a new table called newCounties with the same structure as Counties, but contains no bad data. My was to completely replace the contents of Counties with the contents of newCounties. The problem is: several other tables have Foreign Key constraints placed on Counties. Therefore, Pg will not let me 'DELETE FROM Counties;", nor will it let me "DROP TABLE Counties;" I'm perplexed. Can someone suggest how I can best get data from Counties to look just like newCounties? Mark begin:vcard fn:Mark Fenbers n:Fenbers;Mark org:DoC/NOAA/NWS/OHRFC adr:;;1901 South SR 134;Wilmington;OH;45177-9708;USA email;internet:[EMAIL PROTECTED] title:Sr. HAS Meteorologist tel;work:937-383-0430 x246 x-mozilla-html:TRUE url:http://weather.gov/ohrfc version:2.1 end:vcard ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [SQL] Replacing a table with constraints
Use Drop table YOUR_TABLE cascade Jhon CarrilloIngeniero en ComputaciónCaracas - Venezuela - Original Message - From: Mark Fenbers To: pgsql-sql@postgresql.org Sent: Friday, May 13, 2005 2:38 PM Subject: [SQL] Replacing a table with constraints I have a table called Counties which partially contains a lot bad data. By" bad data", I mean some records are missing; some exist and shouldn't; and some records have fields with erroneous information. However, the majority of the data in the table is accurate. I have built/loaded a new table called newCounties with the same structure as Counties, but contains no bad data. My was to completely replace the contents of Counties with the contents of newCounties. The problem is: several other tables have Foreign Key constraints placed on Counties. Therefore, Pg will not let me 'DELETE FROM Counties;", nor will it let me "DROP TABLE Counties;" I'm perplexed. Can someone suggest how I can best get data from Counties to look just like newCounties?Mark ---(end of broadcast)---TIP 8: explain analyze is your friend
Re: [SQL] Replacing a table with constraints
True, but Counties has about 8 or 9 rules, view, or pk constraints attached to it. I don't want to break all these unless I knew of a way to save off the SQL for them beforehand so I can easily rebuild them... Mark Ing. Jhon Carrillo wrote: Use Drop table YOUR_TABLE cascade Jhon Carrillo Ingeniero en Computación Caracas - Venezuela - Original Message - From: Mark Fenbers To: pgsql-sql@postgresql.org Sent: Friday, May 13, 2005 2:38 PM Subject: [SQL] Replacing a table with constraints I have a table called Counties which partially contains a lot bad data. By" bad data", I mean some records are missing; some exist and shouldn't; and some records have fields with erroneous information. However, the majority of the data in the table is accurate. I have built/loaded a new table called newCounties with the same structure as Counties, but contains no bad data. My was to completely replace the contents of Counties with the contents of newCounties. The problem is: several other tables have Foreign Key constraints placed on Counties. Therefore, Pg will not let me 'DELETE FROM Counties;", nor will it let me "DROP TABLE Counties;" I'm perplexed. Can someone suggest how I can best get data from Counties to look just like newCounties? Mark ---(end of broadcast)--- TIP 8: explain analyze is your friend begin:vcard fn:Mark Fenbers n:Fenbers;Mark org:DoC/NOAA/NWS/OHRFC adr:;;1901 South SR 134;Wilmington;OH;45177-9708;USA email;internet:[EMAIL PROTECTED] title:Sr. HAS Meteorologist tel;work:937-383-0430 x246 x-mozilla-html:TRUE url:http://weather.gov/ohrfc version:2.1 end:vcard ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://archives.postgresql.org
Re: [SQL] Replacing a table with constraints
Are the constraints deferrable? If they are, then you can replace the data with a single transaction. If not, then you'll have to look at disabling triggers for the update. On Fri, 2005-05-13 at 14:55, Mark Fenbers wrote: > True, but Counties has about 8 or 9 rules, view, or pk constraints > attached to it. I don't want to break all these unless I knew of a > way to save off the SQL for them beforehand so I can easily rebuild > them... > Mark > > Ing. Jhon Carrillo wrote: > > Use Drop table YOUR_TABLE cascade > > > > Jhon Carrillo > > Ingeniero en ComputaciÃn > > Caracas - Venezuela > > > > > > > > - Original Message - > > From: Mark Fenbers > > To: pgsql-sql@postgresql.org > > Sent: Friday, May 13, 2005 2:38 PM > > Subject: [SQL] Replacing a table with constraints > > > > I have a table called Counties which partially contains a > > lot bad data. By" bad data", I mean some records are > > missing; some exist and shouldn't; and some records have > > fields with erroneous information. However, the majority of > > the data in the table is accurate. I have built/loaded a > > new table called newCounties with the same structure as > > Counties, but contains no bad data. My was to completely > > replace the contents of Counties with the contents of > > newCounties. The problem is: several other tables have > > Foreign Key constraints placed on Counties. Therefore, Pg > > will not let me 'DELETE FROM Counties;", nor will it let me > > "DROP TABLE Counties;" > > > > I'm perplexed. Can someone suggest how I can best get data > > from Counties to look just like newCounties? > > > > Mark > > > > > > > > > > ---(end of > > broadcast)--- > > TIP 8: explain analyze is your friend > > > __ > ---(end of broadcast)--- > TIP 6: Have you searched our list archives? > >http://archives.postgresql.org ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [SQL] Replacing a table with constraints
On Fri, 2005-05-13 at 14:38 -0400, Mark Fenbers wrote: > I have a table called Counties which partially contains a lot bad > data. By" bad data", I mean some records are missing; some exist and > shouldn't; and some records have fields with erroneous information. > However, the majority of the data in the table is accurate. I have > built/loaded a new table called newCounties with the same structure as > Counties, but contains no bad data. My was to completely replace the > contents of Counties with the contents of newCounties. The problem > is: several other tables have Foreign Key constraints placed on > Counties. Therefore, Pg will not let me 'DELETE FROM Counties;", nor > will it let me "DROP TABLE Counties;" > > I'm perplexed. Can someone suggest how I can best get data from > Counties to look just like newCounties? assuming same primary key on these 2 tables, you have to consider these cases: a) records in Counties not in newCounties b) records in newCounties existing in Counties, but different c) records in newCounties also correct in Counties d) records in newCounties missing from Counties a) get rid of extra records: delete from Counties where primarykey not in (select primarykey from newCounties); if you hit foreign key constrains, you need to look at your data a bit more, anyways b) update erroneous records: update Counties from newCounties set col1= newCounties.col1, col2= newCounties.col2, col3= newCounties.col3, ... from newCounties where primarykey=newCounties.primarykey and (Counties.col1 <> newCounties.col1 OR Counties.col2 <> newCounties.col2 OR Counties.col3 <> newCounties.col3 ... ); c) nothing to do here d) insert into Counties select * from newCounties where primarykey not in (select primarykey from Counties); test case: test=# create table c (p int, col1 int, col2 int); CREATE TABLE test=# insert into c values (1,1,1); -- correct values INSERT 7693959 1 test=# insert into c values (2,1,2); -- incorrect INSERT 7693960 1 test=# insert into c values (9,9,9); -- extra value INSERT 7693961 1 test=# create table newc (p int, col1 int, col2 int); CREATE TABLE test=# insert into newc values (1,1,1); -- correct values INSERT 7693964 1 test=# insert into newc values (2,2,2); -- incorrect in c INSERT 7693965 1 test=# insert into newc values (3,3,3); -- missing in c INSERT 7693966 1 test=# delete from c where p not in (select p from newc); DELETE 1 test=# update c set col1=n.col1, col2=n.col2 test-# from newc as n test-# where c.p=n.p and (c.col1<>n.col1 or c.col2<>n.col2); UPDATE 1 test=# insert into c select * from newc where p not in (select p from c); INSERT 7693967 1 test=# select * from c; p | col1 | col2 ---+--+-- 1 |1 |1 2 |2 |2 3 |3 |3 (3 rows) note: b) and c) can be merged and simplified if you don't mind updating unchanged records: update Counties from newCounties set col1= newCounties.col1, col2= newCounties.col2, col3= newCounties.col3, ... from newCounties where primarykey=newCounties.primarykey; gnari ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
