Diagrams

What are these diagrams in each database used for?
If I make a link betwwen two tables in a diagram ,,does it affect the
relationships'
Why dosn't it detect the relations between the tables'
ThanksThey are a simple ERD tool for visualising the schema of your database.
Changes to relationships in a diagram will affect your schema (it will
prompt to warn you).If you don't have foreign key relationships setup then
it won't be able to automatically determine the table relations.
HTH
Jasper Smith (SQL Server MVP)
I support PASS - the definitive, global
community for SQL Server professionals -
http://www.sqlpass.org
"Reza Alirezaei" <anonymous@.discussions.microsoft.com> wrote in message
news:e$xI1SEPEHA.1388@.TK2MSFTNGP09.phx.gbl...
> What are these diagrams in each database used for?
> If I make a link betwwen two tables in a diagram ,,does it affect the
> relationships'
> Why dosn't it detect the relations between the tables'
> Thanks
>|||How can I setup a foreign key while I'm designing a tabel?
"Jasper Smith" <jasper_smith9@.hotmail.com> wrote in message
news:O3a59pEPEHA.252@.TK2MSFTNGP10.phx.gbl...
> They are a simple ERD tool for visualising the schema of your database.
> Changes to relationships in a diagram will affect your schema (it will
> prompt to warn you).If you don't have foreign key relationships setup then
> it won't be able to automatically determine the table relations.
> --
> HTH
> Jasper Smith (SQL Server MVP)
> I support PASS - the definitive, global
> community for SQL Server professionals -
> http://www.sqlpass.org
>
> "Reza Alirezaei" <anonymous@.discussions.microsoft.com> wrote in message
> news:e$xI1SEPEHA.1388@.TK2MSFTNGP09.phx.gbl...
>|||Reza,
CREATE TABLE master_table
(
master_id INT NOT NULL PRIMARY KEY,
master_name VARCHAR(200)
)
--One way of creating a Foreign Key
CREATE TABLE child_table
(
child_id INT NOT NULL PRIMARY KEY,
master_id INT NOT NULL REFERENCES master_table(master_id),
child_name VARCHAR(200)
)
--Another way, using Alter table
ALTER TABLE [dbo].[child_tyable] ADD
FOREIGN KEY
(
[master_id]
) REFERENCES [dbo].[master_table] (
[master_id]
)
GO
You can find basic tsql syntax in BooksOnLine.
Dinesh
SQL Server MVP
--
--
SQL Server FAQ at
http://www.tkdinesh.com
"Reza Alirezaei" <anonymous@.discussions.microsoft.com> wrote in message
news:#jDyX8EPEHA.3016@.tk2msftngp13.phx.gbl...
> How can I setup a foreign key while I'm designing a tabel?
> "Jasper Smith" <jasper_smith9@.hotmail.com> wrote in message
> news:O3a59pEPEHA.252@.TK2MSFTNGP10.phx.gbl...
then[vbcol=seagreen]
>|||You can also drag and drop in columns in the diagram itself to visually
create your relationships however I would recomend the approcah from Dinesh
i.e. explicitly create them as part of your schema as its too easy to get
things the wrong way round using the diagram tool.
HTH
Jasper Smith (SQL Server MVP)
I support PASS - the definitive, global
community for SQL Server professionals -
http://www.sqlpass.org
"Dinesh T.K" <tkdinesh@.nospam.mail.tkdinesh.com> wrote in message
news:uaAAHKFPEHA.3052@.TK2MSFTNGP09.phx.gbl...
> Reza,
> CREATE TABLE master_table
> (
> master_id INT NOT NULL PRIMARY KEY,
> master_name VARCHAR(200)
> )
> --One way of creating a Foreign Key
> CREATE TABLE child_table
> (
> child_id INT NOT NULL PRIMARY KEY,
> master_id INT NOT NULL REFERENCES master_table(master_id),
> child_name VARCHAR(200)
> )
> --Another way, using Alter table
> ALTER TABLE [dbo].[child_tyable] ADD
> FOREIGN KEY
> (
> [master_id]
> ) REFERENCES [dbo].[master_table] (
> [master_id]
> )
> GO
> You can find basic tsql syntax in BooksOnLine.
>
> --
> Dinesh
> SQL Server MVP
> --
> --
> SQL Server FAQ at
> http://www.tkdinesh.com
> "Reza Alirezaei" <anonymous@.discussions.microsoft.com> wrote in message
> news:#jDyX8EPEHA.3016@.tk2msftngp13.phx.gbl...
database.[vbcol=seagreen]
> then
message[vbcol=seagreen]
the[vbcol=seagreen]
>