Database

Re: how can i index the column ??

31-May-06 12:58

Hi ,
i have a key that migrate from a table reserver to an other table reservation
that mean i have a forieng key called N°Reser in the reservation table

well , now i want that this N°Reser displayed just once in the reservation table

i meant 1 reserver can do 1,1 reservation can you tell me how should i do that in sql ??

because the default relashion gave me 1,n

thank you very much

try to be good if you can't be the best

Colin Angus Mackay31-May-06 23:38

Colin Angus Mackay

31-May-06 23:38

Mohammed Amine wrote:
because the default relashion gave me 1,n

n can represent 0, 1 or many. If you want to force a one-to-one relationship then you can put a second relationship in place 1-to-many going in the opposite direction. If you have two tables with a one-to-many and a many-to-one between them they end up forcing a one-to-one. (Actually, not quite - You can have a zero on one side, i.e. one-to-zero)

I'm curious. Why do you need a foreign key? Surely the primary key of of both will be the same?

one-to-one relationships can also be symptomatic of two tables that ought to be one table. Have you explored this possibility?

"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question."
--Charles Babbage (1791-1871)
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attach a database with code

Mohammed Amine31-May-06 12:55

31-May-06 12:55

can you tell me please how can i attach a database to the server just with code ?? i use VS 2003

i have the two files Mdf & Ldf one & i want to attach them to the server just with code

thank you very much

try to be good if you can't be the best

albCode31-May-06 23:32

albCode

31-May-06 23:32

same command which is used in T-SQL to attach DataBase use in ur application.
It's pretty easy

Eric Dahlvang1-Jun-06 2:56

1-Jun-06 2:56

SQL Server Books Online

sp_attach_db
Attaches a database to a server.

Syntax
sp_attach_db [ @dbname = ] 'dbname'
, [ @filename1 = ] 'filename_n' [ ,...16 ]

Examples
This example attaches two files from pubs to the current server.

EXEC sp_attach_db @dbname = N'pubs',
@filename1 = N'c:\Program Files\Microsoft SQL Server\MSSQL\Data\pubs.mdf',
@filename2 = N'c:\Program Files\Microsoft SQL Server\MSSQL\Data\pubs_log.ldf'

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Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
- Laurence J. Peters

Mohammed Amine1-Jun-06 5:39

1-Jun-06 5:39

well , thanks but i see that you used a stored procedure actually i didn't understand very well can you add some explanation please ??

thank you

try to be good if you can't be the best

Eric Dahlvang1-Jun-06 7:07

1-Jun-06 7:07

using System.Data;
using System.Data.SqlClient;

SqlConnection conn = new  SqlConnection();
conn.ConnectionString = "Data Source=(local);Initial Catalog=master;Integrated Security=SSPI";
conn.Open();

SqlCommand myCommand = conn.CreateCommand();
myCommand.CommandText = "EXEC sp_attach_db @dbname = 'ATestDB',@filename1 = 'C:\\TestPath\\ATestDB_Data.MDF',@filename2 = 'C:\\TestPath\\ATestDB_Log.LDF'";
myCommand.ExecuteScalar();

----------
Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
- Laurence J. Peters

Mohammed Amine1-Jun-06 7:23

1-Jun-06 7:23

thanks but what i don't understand is that how the vb.net will understand this ?? there is no procedure named like that in ma data base & he won't know it

can you explain from where you brought this procedure & how it works

thank you for your help but i want to understand but i can't because i have no procedure called like that

thank you for helping again Smile | :)

try to be good if you can't be the best

Eric Dahlvang1-Jun-06 7:55

1-Jun-06 7:55

sp_attach_db is a system stored procedure that is in the SQL Server master database.
If you really don't want to use it, you can use what is below (which is all the sp_attach_db does).

Also, I put this in vb.net - the last thing I posted was C#.

Imports System.Data
Imports System.Data.SqlClient

Dim conn As New SqlConnection
Dim myCommand As SqlCommand

conn.ConnectionString = "Data Source=(local);Initial Catalog=master;Integrated Security=SSPI"
conn.Open()

myCommand = conn.CreateCommand()
myCommand.CommandText = "CREATE DATABASE [ATestDB] ON (FILENAME = 'C:\TestPath\ATestDB_Data.MDF'), (FILENAME = 'C:\TestPath\ATestDB_Log.LDF') FOR ATTACH"

myCommand.ExecuteScalar()

Just change the name of ATestDB to whatever yours is, and the paths and filenames too.

----------
Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
- Laurence J. Peters

-- modified at 13:55 Thursday 1st June, 2006

Mohammed Amine1-Jun-06 10:28

1-Jun-06 10:28

Hi , thank you very very much this last one worked thank you i don't know without you what i would do thnx again

now if you permit i want to ask you some other things abt this

well , first when i create this database with the way you told me it work

but now if i already have the database attached i have to change ma code to :

conn.ConnectionString = "Data Source=(local);InitialCatalog=MyDataBase;Integrated Security=SSPI"

& i have to delete this 4 lines from code :

conn.Open()myCommand = conn.CreateCommand()myCommand.CommandText = "CREATE DATABASE [ATestDB] ON (FILENAME = 'C:\TestPath\ATestDB_Data.MDF'), (FILENAME = 'C:\TestPath\ATestDB_Log.LDF') FOR ATTACH"myCommand.ExecuteScalar()

like this i will just extract records from the database this is first

second thing i want to detect the name of the server automatically

like this :

conn.ConnectionString = "Data Source= <big>Here i have to write the name of the server but i don't know what is it name so how can i know without asking the user ?? </big>;InitialCatalog=MyDataBase;Integrated Security=SSPI"

thank you very much for help Smile | :)

try to be good if you can't be the best

Eric Dahlvang1-Jun-06 11:13