sql - powerapps - Agregar clave principal a la tabla existente

powerapps ejemplos

Question

Tengo una tabla existente llamada Persion . En esta tabla tengo 5 columnas:

• persionId
• Pname
• PMid
• Pdescription
• Pamt

Cuando creé esta tabla, configuré PersionId y Pname como la clave principal .

Ahora quiero incluir una columna más en la clave principal - PMID. ¿Cómo puedo escribir una declaración ALTER para hacer esto? (Ya tengo 1000 registros en la tabla)

Answer 1

Creo que algo como esto debería funcionar

-- drop current primary key constraint
ALTER TABLE dbo.persion 
DROP CONSTRAINT PK_persionId;
GO

-- add new auto incremented field
ALTER TABLE dbo.persion 
ADD pmid BIGINT IDENTITY;
GO

-- create new primary key constraint
ALTER TABLE dbo.persion 
ADD CONSTRAINT PK_persionId PRIMARY KEY NONCLUSTERED (pmid, persionId);
GO

Answer 2

Intenta usar este código:

ALTER TABLE `table name` 
    CHANGE COLUMN `column name` `column name` datatype NOT NULL, 
    ADD PRIMARY KEY (`column name`) ;

Answer 3

La restricción PRIMARY KEY identifica de forma única cada registro en una tabla de base de datos. Las claves primarias deben contener valores UNIQUE y la columna no puede contener valores NULL.

  -- DROP current primary key 
  ALTER TABLE tblPersons DROP CONSTRAINT <constraint_name>
  Example:
  ALTER TABLE tblPersons 
  DROP CONSTRAINT P_Id;


  -- ALTER TABLE tblpersion
  ALTER TABLE tblpersion add primary key (P_Id,LastName)

Answer 4

Nigromancia
Solo en caso de que alguien tenga un esquema tan bueno para trabajar como yo ...
Aquí es cómo hacerlo correctamente:

En este ejemplo, el nombre de la tabla es dbo.T_SYS_Language_Forms, y el nombre de la columna es LANG_UID

-- First, chech if the table exists...
IF 0 < (
    SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES 
    WHERE TABLE_TYPE = ''BASE TABLE''
    AND TABLE_SCHEMA = ''dbo''
    AND TABLE_NAME = ''T_SYS_Language_Forms''
)
BEGIN
    -- Check for NULL values in the primary-key column
    IF 0 = (SELECT COUNT(*) FROM T_SYS_Language_Forms WHERE LANG_UID IS NULL)
    BEGIN
        ALTER TABLE T_SYS_Language_Forms ALTER COLUMN LANG_UID uniqueidentifier NOT NULL 

        -- No, don''t drop, FK references might already exist...
        -- Drop PK if exists (it is very possible it does not have the name you think it has...)
        -- ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT pk_constraint_name 
        --DECLARE @pkDropCommand nvarchar(1000) 
        --SET @pkDropCommand = N''ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT '' + QUOTENAME((SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
        --WHERE CONSTRAINT_TYPE = ''PRIMARY KEY'' 
        --AND TABLE_SCHEMA = ''dbo'' 
        --AND TABLE_NAME = ''T_SYS_Language_Forms'' 
        ----AND CONSTRAINT_NAME = ''PK_T_SYS_Language_Forms'' 
        --))
        ---- PRINT @pkDropCommand 
        --EXECUTE(@pkDropCommand) 
        -- Instead do
        -- EXEC sp_rename ''dbo.T_SYS_Language_Forms.PK_T_SYS_Language_Forms1234565'', ''PK_T_SYS_Language_Forms'';

        -- Check if they keys are unique (it is very possible they might not be)        
        IF 1 >= (SELECT TOP 1 COUNT(*) AS cnt FROM T_SYS_Language_Forms GROUP BY LANG_UID ORDER BY cnt DESC)
        BEGIN

            -- If no Primary key for this table
            IF 0 =  
            (
                SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS 
                WHERE CONSTRAINT_TYPE = ''PRIMARY KEY'' 
                AND TABLE_SCHEMA = ''dbo'' 
                AND TABLE_NAME = ''T_SYS_Language_Forms'' 
                -- AND CONSTRAINT_NAME = ''PK_T_SYS_Language_Forms'' 
            )
                ALTER TABLE T_SYS_Language_Forms ADD CONSTRAINT PK_T_SYS_Language_Forms PRIMARY KEY CLUSTERED (LANG_UID ASC)
            ;

        END -- End uniqueness check
        ELSE
            PRINT ''FSCK, this column has duplicate keys, and can thus not be changed to primary key...'' 
    END -- End NULL check
    ELSE
        PRINT ''FSCK, need to figure out how to update NULL value(s)...'' 
END 

Answer 5

Por favor, intente esto-

ALTER TABLE TABLE_NAME DROP INDEX `PRIMARY`, ADD PRIMARY KEY (COLUMN1, COLUMN2,..);

Answer 6

Si agrega restricción de clave principal

ALTER TABLE <TABLE NAME> ADD CONSTRAINT <CONSTRAINT NAME> PRIMARY KEY <COLUMNNAME>  

por ejemplo:

ALTER TABLE DEPT ADD CONSTRAINT PK_DEPT PRIMARY KEY (DEPTNO)

Answer 7

eliminar la restricción y recrearla

alter table Persion drop CONSTRAINT <constraint_name>

alter table Persion add primary key (persionId,Pname,PMID)

editar:

puedes encontrar el nombre de la restricción usando la consulta a continuación:

select OBJECT_NAME(OBJECT_ID) AS NameofConstraint
FROM sys.objects
where OBJECT_NAME(parent_object_id)=''Persion''
and type_desc LIKE ''%CONSTRAINT''

Answer 8

-- create new primary key constraint
ALTER TABLE dbo.persion 
ADD CONSTRAINT PK_persionId PRIMARY KEY NONCLUSTERED (pmid, persionId);

es una mejor solución porque tienes control sobre el nombre de la clave primaria.

Es mejor que solo usar

ALTER TABLE Persion ADD PRIMARY KEY(persionId,Pname,PMID)

que genera nombres aleatorios y puede causar problemas al crear scripts o al comparar bases de datos

Answer 9

ALTER TABLE TABLE_NAME ADD PRIMARY KEY(`persionId`,`Pname`,`PMID`)