Обсуждение: primary keys
Hi, I want to create a table which has 2 columns, and both columns have to be primary key (or: together they are the primary key). How can I do this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. Thanks Huub
A table can only have ONE primary key. It can have additional indexes with a UNIQUE restriction, thereby forcing the second field to be as good as a primary key. That is probably what you are looking for, however, you can also in PG Admin II select multiple fields as being the member of the primary key. Terry Fielder Network Engineer Great Gulf Homes / Ashton Woods Homes terry@greatgulfhomes.com > -----Original Message----- > From: pgsql-sql-owner@postgresql.org > [mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Huub > Sent: Wednesday, November 06, 2002 9:19 AM > To: pgsql-sql@postgresql.org > Subject: [SQL] primary keys > > > Hi, > > I want to create a table which has 2 columns, and both > columns have to > be primary key (or: together they are the primary key). How can I do > this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. > > Thanks > > Huub > > > ---------------------------(end of > broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster >
Hi, For example you can do something like that: CREATE TABLE "try" ( "field1" TEXT NOT NULL, "field2" INT4 NOT NULL,"field3" TEXT, PRIMARY KEY(field1, field2)); ************************************** Rachel.Vaudron@lazaret.unice.fr Laboratoire de prehistoire du Lazaret33 bis bd Franck Pilatte 06300 Nice tel:04-92-00-17-37/fax:04-92-00-17-39 ******** Windows a bug's life ******** On Wed, 6 Nov 2002, Huub wrote: > Hi, > > I want to create a table which has 2 columns, and both columns have to > be primary key (or: together they are the primary key). How can I do > this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. > > Thanks > > Huub > > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster >
On Wed, Nov 06, 2002 at 15:18:38 +0100, Huub <v.niekerk@freeler.nl> wrote: > Hi, > > I want to create a table which has 2 columns, and both columns have to > be primary key (or: together they are the primary key). How can I do > this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. You can use a PRIMARY KEY table constraint. You can the SQL command documentation for the CREATE TABLE command.
How do you select these sub Primary Keys? I tried using Shift-Select, Ctrl_Selec, but doesn't work. Thanks Sangeetha -----Original Message----- From: pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-owner@postgresql.org]On Behalf Of terry@greatgulfhomes.com Sent: Thursday, November 07, 2002 8:54 AM To: 'Huub'; pgsql-sql@postgresql.org Subject: Re: [SQL] primary keys A table can only have ONE primary key. It can have additional indexes with a UNIQUE restriction, thereby forcing the second field to be as good as a primary key. That is probably what you are looking for, however, you can also in PG Admin II select multiple fields as being the member of the primary key. Terry Fielder Network Engineer Great Gulf Homes / Ashton Woods Homes terry@greatgulfhomes.com > -----Original Message----- > From: pgsql-sql-owner@postgresql.org > [mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Huub > Sent: Wednesday, November 06, 2002 9:19 AM > To: pgsql-sql@postgresql.org > Subject: [SQL] primary keys > > > Hi, > > I want to create a table which has 2 columns, and both > columns have to > be primary key (or: together they are the primary key). How can I do > this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. > > Thanks > > Huub > > > ---------------------------(end of > broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@postgresql.org so that your message can get through to the mailing list cleanly
On Wed, 6 Nov 2002, Huub wrote: > Hi, > > I want to create a table which has 2 columns, and both columns have to > be primary key (or: together they are the primary key). How can I do > this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. I dont know the way in pgAdminII, but from psql simply give: CREATE TABLE foo( name varchar(20) NOT NULL, id int4 NOT NULL, PRIMARY KEY (name,id)); > > Thanks > > Huub > > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > ================================================================== Achilleus Mantzios S/W Engineer IT dept Dynacom Tankers Mngmt Nikis 4, Glyfada Athens 16610 Greece tel: +30-10-8981112 fax: +30-10-8981877 email: achill@matrix.gatewaynet.com mantzios@softlab.ece.ntua.gr
terry@greatgulfhomes.com wrote: > A table can only have ONE primary key. It can have additional indexes > with > a UNIQUE restriction, thereby forcing the second field to be as good as a > primary key. > > That is probably what you are looking for, however, you can also in PG > Admin > II select multiple fields as being the member of the primary key. > > > Terry Fielder > Network Engineer > Great Gulf Homes / Ashton Woods Homes > terry@greatgulfhomes.com > > > > > >-----Original Message----- > >From: pgsql-sql-owner@postgresql.org > >[mailto:pgsql-sql-owner@postgresql.org]On Behalf Of Huub > >Sent: Wednesday, November 06, 2002 9:19 AM > >To: pgsql-sql@postgresql.org > >Subject: [SQL] primary keys > > > > > >Hi, > > > >I want to create a table which has 2 columns, and both > >columns have to > >be primary key (or: together they are the primary key). How can I do > >this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. > > > >Thanks > > > >Huub > > > > > >---------------------------(end of > >broadcast)--------------------------- > >TIP 4: Don't 'kill -9' the postmaster > > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly Thanks..problem solved.. Huub
Uz.ytkownik Huub napisa?:> Hi,>> I want to create a table which has 2 columns, and both columns have to> be primary key (or:together they are the primary key). How can I do> this using SQL? Using pgAdminII for Postgres7.2.2 on RH8. Dependent on what you need: 1) you can create primary key based on 2 fields 2) you can't create 2 primary keys - but you can create primary key on first field and create unique index on second one. Tomasz Myrta