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Tengo una situacion que luce así
La siguiente tabla puede tener foreignkeys de 2 tabls diferentes y no se
como crear o si no se puede crear esa relacion conbinada de 2 tablas

tbTrabajosYMetas
xid, tablecode, code
1, 'mts', 1
1, 'mts', 2
1, 'trb', 1
2, 'trb', 1
Los 3 campos son la llave primaria, tablecode y code son el foreignkey

La segunda tabla
tbMetas
tablecode, code, descripcion, etc
'mts', 1, 'meta1' ..
'mts', 2, 'meta2' ..

La Tercera tabla
tbTrabajos- tablecode y code Es la primaryKey al igual que en la tabla
anterior
tablecode, code, descripcion, hora, etc
'trb', 1, 'trabajo1', ..
'trb', 2, 'trabajo2', ..
Jan 11 '07 #1
2 2111
Lucas Hernandez wrote:
Tengo una situacion que luce así
La siguiente tabla puede tener foreignkeys de 2 tabls diferentes y no se
como crear o si no se puede crear esa relacion conbinada de 2 tablas

tbTrabajosYMetas
xid, tablecode, code
1, 'mts', 1
1, 'mts', 2
1, 'trb', 1
2, 'trb', 1
Los 3 campos son la llave primaria, tablecode y code son el foreignkey

La segunda tabla
tbMetas
tablecode, code, descripcion, etc
'mts', 1, 'meta1' ..
'mts', 2, 'meta2' ..

La Tercera tabla
tbTrabajos- tablecode y code Es la primaryKey al igual que en la tabla
anterior
tablecode, code, descripcion, hora, etc
'trb', 1, 'trabajo1', ..
'trb', 2, 'trabajo2', ..
tbTrabajosSinMetas
xid, code
1, 1
1, 2

tbMetasSinTrabajos
xid, code
1, 1
2, 1

select xid, 'trb' as tablecode, code from tbTrabajosSinMetas
union
select xid, 'mts' as tablecode, code from tbMetasSinTrabajos
Jan 12 '07 #2
Lucas Hernandez (lu******@fuse.net) writes:
Tengo una situacion que luce así
La siguiente tabla puede tener foreignkeys de 2 tabls diferentes y no se
como crear o si no se puede crear esa relacion conbinada de 2 tablas

tbTrabajosYMetas
xid, tablecode, code
1, 'mts', 1
1, 'mts', 2
1, 'trb', 1
2, 'trb', 1
Los 3 campos son la llave primaria, tablecode y code son el foreignkey

La segunda tabla
tbMetas
tablecode, code, descripcion, etc
'mts', 1, 'meta1' ..
'mts', 2, 'meta2' ..

La Tercera tabla
tbTrabajos- tablecode y code Es la primaryKey al igual que en la tabla
anterior
tablecode, code, descripcion, hora, etc
'trb', 1, 'trabajo1', ..
'trb', 2, 'trabajo2', ..
El mejor es de usar dos campos de code in tbTrabajosYMetas, un per
tbTrabajos y un per tbMetas. Con esos non es un problema con
foreignkey. Es también una buena idea de haber un CHECK constraint:

CHECK (code_trabajo IS NOT NULL AND code_meta IS NULL OR
code_trabajo IS NULL AND code_meta IS NOT NULL)

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pro...ads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinf...ons/books.mspx
Jan 12 '07 #3

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