Restricción única en varias columnas
CREATE TABLE [dbo].[user](
[userID] [int] IDENTITY(1,1) NOT NULL,
[fcode] [int] NULL,
[scode] [int] NULL,
[dcode] [int] NULL,
[name] [nvarchar](50) NULL,
[address] [nvarchar](50) NULL,
CONSTRAINT [PK_user_1] PRIMARY KEY CLUSTERED
(
[userID] ASC
)
) ON [PRIMARY]
GO
¿Cómo agrego una restricción única para las columnas fcode, scode, dcode
con t-sql
y/o management studio
? fcode, scode, dcode
deben ser únicos juntos.
201
4 answers
Al usar la definición de restricción en la creación de tablas, puede especificar una o varias restricciones que abarcan varias columnas. La sintaxis, simplificada de la documentación de technet , está en la forma de:
CONSTRAINT constraint_name UNIQUE [ CLUSTERED | NONCLUSTERED ]
(
column [ ASC | DESC ] [ ,...n ]
)
Por lo tanto, la definición de la tabla resuting sería:
CREATE TABLE [dbo].[user](
[userID] [int] IDENTITY(1,1) NOT NULL,
[fcode] [int] NULL,
[scode] [int] NULL,
[dcode] [int] NULL,
[name] [nvarchar](50) NULL,
[address] [nvarchar](50) NULL,
CONSTRAINT [PK_user_1] PRIMARY KEY CLUSTERED
(
[userID] ASC
),
CONSTRAINT [UQ_codes] UNIQUE NONCLUSTERED
(
[fcode], [scode], [dcode]
)
) ON [PRIMARY]
254
Author: devmake,
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2016-12-29 18:22:16
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2016-12-29 18:22:16
Si la tabla ya está creada en la base de datos, puede agregar una restricción única más adelante utilizando esta consulta SQL:
ALTER TABLE dbo.User
ADD CONSTRAINT ucCodes UNIQUE (fcode, scode, dcode)
351
Author: marc_s,
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2015-10-26 09:42:47
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2015-10-26 09:42:47
Esto también se puede hacer en la GUI. Este es un ejemplo que agrega una restricción única de varias columnas a una tabla existente.
- Debajo de la tabla, haga clic con el botón derecho en Indexes->Click/hover New Index->Click Non-Clustered Index...
- Se dará un nombre de índice predeterminado, pero es posible que desee cambiarlo. Marque la casilla Unique y haga clic en Add... botón
- Compruebe las columnas que desea incluir
Haga clic en OK en cada ventana y listo.
34
Author: Tony L.,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2016-08-18 15:03:13
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2016-08-18 15:03:13
USE [TSQL2012]
GO
/****** Object: Table [dbo].[Table_1] Script Date: 11/22/2015 12:45:47 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Table_1](
[seq] [bigint] IDENTITY(1,1) NOT NULL,
[ID] [int] NOT NULL,
[name] [nvarchar](50) NULL,
[cat] [nvarchar](50) NULL,
CONSTRAINT [PK_Table_1] PRIMARY KEY CLUSTERED
(
[ID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
CONSTRAINT [IX_Table_1] UNIQUE NONCLUSTERED
(
[name] ASC,
[cat] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
0
Author: Muhanned Kamil,
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2017-11-15 16:51:34
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2017-11-15 16:51:34