I have three tables: Employee, Emp_Address and Emp_AddressDetail.
Employee table is master and Emp_Address is detail.
Emp_Address is master and Emp_AddressDetail is detail.
I want to copy all rows from a table to another table.
How can I do it?
If I understand your question correct you want to insert data from one table to another? If so, you should have a look at the INTO statement. http://msdn.microsoft.com/en-us/library/ms188029.aspx
SELECT * INTO dbo.OneTable FROM Production.AnotherTable
If the tables have foreign keys defined, and those foreign key definitions need to be set on the new database, than you need to take a look at the data diagrams, and identify any tables that do not have foreign key columns. In your case the copy order will be Employee, Emp_Address, Emp_AddressDetail
If you do not have explicit SQL Server maintained foreign keys, or if the foreign keys are not set on the target database, you can just copy the data in any order you like.
Note that it's entirely possible to paint yourself into a corner, e.g. if there was field in the Employee table called PrimaryAddress that would be a foreign key to the Emp_Address table.
Related
I am developing a system in which I have a table Employees with multiple columns related to employees. I have a column for the JobTitle and another column for Department.
In my current design, the JobTitle & the Department columns are compound foreign keys in the Employees table and they are linked with the Groups table which has 2 columns compound primary key (JobTitle & Department) and an extra column for the job description.
I am not happy about this design because I think that linking 2 tables using 2 compound varchar columns is not good for the performance, and I think it would be better to have an Integer column (autonumber) JobTitleID used as the primary key in the Groups table and as a foreign key in the Employees table instead of the the textual JobTitle & the Department columns.
But I had to do this because when I import the employees list (Excel) into my Employees table it can just be directly mapped (JobTitle --> JobTitle & Department --> Department). Otherwise if I am using an integer index as primary key I would have then to manually rename the textual JobTitle column in the excel sheet to a number based on the generated keys from the Groups table in order to import.
Is it fine to keep my database design like this (textual compound primary key linked with textual compound foreign key)? If not, then if I used an integer column in the Groups table as primary key and the same as a foreign key in the Employees table then how can I import the employees list from excel directly to Employees table?
Is it possible to import the list from Excel to SQL Server in a way that the textual JobTitle from the excel sheet will be automatically translated to the corespondent JobTitleID from the Groups table? This would be the best solution, I can then add JobTitleID column in the Groups table as a primary key and as a foreign key in the Employees table.
Thank you,
It sounds like you are trying to make the database table design fit the import of the excel file which is not such a good idea. Forget the excel file and design your db tables first with correct primary keys and relationships. This means either int, bigint or guids for primary keys. This will keep you out of trouble unless you absolutely know the key is unique such as in a SSN. The when you import, then populate the departments and job titles into their respective tables creating their primary keys. Now that they are populated, add those keys to the excel file that can be imported into the employees table.
This is just an example of how I would solve this problem. It is not wrong to use multiple columns as the key but it will definitely keep you out of harms way if you stick with int, bigint or guids for your primary keys.
Look at the answer in this post: how-to-use-bulk-insert...
I would create a simple Stored Procedure that imports your excel data into a temporary unrestricted STAGING table and then do the INSERT into your real table by doing the corresponding table joins to get the right foreign keys and dump the rows that failed to import into an IMPORT FAIL table. Just some thoughts...
I have a table, Contacts, with a primary key of ContactID, which is an identity column. I have another table, Person, with a primary key of PersonID that is a foreign key to ContactID. When I insert a record into Person, I would like PersonID to pull the corresponding identity from ContactID in Contact.
In Access, I simply make a query that references both tables, and it will fill in the foreign key column with the corresponding value in the identity (autonumber) column.
SELECT Person.PersonID, Person.FirstName, Person.MiddleName, Person.LastName, Contact.ContactID, Contact.EmailAddress, Contact.PhoneNumber
FROM (Contact INNER JOIN Person ON Contact.ContactID = Person.PersonID);
How can we achieve this in SQLServer 2008 R2? I have been programming triggers to update the keys, but it seems like there ought to be a better way.
Thank you very much for your assistance.
When you insert to the first table, you use the OUTPUT clause to pull the identity value and then you can use it to insert to the child table.
You can also use scope_identity() to do the same thing, but OUTPUT is the preferred method. Do not under any circumstances use ##Identity as it often will give incorrect results and mess up your data integrity.
Look up how to use them in Books Online.
I have created a simple database in SQL Server Express which consists of three tables: Inventory, Customers, Orders.
I try to connect them in db diagram forcing the primary keys of Inventory and Customers (CarID and CustID) as foreign keys to Orders. However, when I try to save the diagram, I receive an error that does not allow me to save the diagram and link the tables.
The error indicates:
The ALTER TABLE statement conflicted with the FOREIGN KEY constraint
"FK_Orders_Inventory". The conflict occurred in database "AutoLot",
table "dbo.Inventory", column 'CarID'.
FK_Orders_Inventory is the connection between Inventory and Orders. What could be a potential cause of the error?
The data currently in the table is probably not conforming to the constraints you have defined.
Make sure the data is consistent with the constraints before adding them.
In this case, one of the foreign keys you are defining fails because the column you are defining it on (in the Inventory table) contains values that do not exist on the referenced column (CarId) in the foreign table.
You have a CarID value in the child table that does not exist in the parent table.
I need to define a one-to-one relationship, and can't seem to find the proper way of doing it in SQL Server.
Why a one-to-one relationship you ask?
I am using WCF as a DAL (Linq) and I have a table containing a BLOB column. The BLOB hardly ever changes and it would be a waste of bandwidth to transfer it across every time a query is made.
I had a look at this solution, and though it seems like a great idea, I can just see Linq having a little hissy fit when trying to implement this approach.
Any ideas?
One-to-one is actually frequently used in super-type/subtype relationship. In the child table, the primary key also serves as the foreign key to the parent table. Here is an example:
CREATE TABLE Organization
(
ID int PRIMARY KEY,
Name varchar(200),
Address varchar(200),
Phone varchar(12)
)
GO
CREATE TABLE Customer
(
ID int PRIMARY KEY,
AccountManager varchar(100)
)
GO
ALTER TABLE Customer
ADD FOREIGN KEY (ID) REFERENCES Organization(ID)
ON DELETE CASCADE
ON UPDATE CASCADE
GO
Why not make the foreign key of each table unique?
there is no such thing as an explicit one-to-one relationship.
But, by the fact that tbl1.id and tbl2.id are primary keys and tbl2.id is a foreign key referenceing tbl1.id, you have created an implicit 1:0..1 relationship.
Put 1:1 related items into the same row in the same table. That's where "relation" in "relational database" comes from - related things go into the same row.
If you want to reduce size of data traveling over the wire consider either projecting only the needed columns:
SELECT c1, c2, c3 FROM t1
or create a view that only projects relevant columns and use that view when needed:
CREATE VIEW V1 AS SELECT c1, c2, c3 FROM t1
SELECT * FROM t1
UPDATE v1 SET c1=5 WHERE c2=7
Note that BLOBs are stored off-row in SQL Server so you are not saving much disk IO by vertically-partitioning your data. If these were non-BLOB columns you may benefit form vertical partitioning as you described because you will do less disk IO to scan the base table.
How about this. Link the primary key in the first table to the primary key in the second table.
Tab1.ID (PK) <-> Tab2.ID (PK)
My problem was I have a 2 stage process with mandatory fields in both. The whole process could be classed as one episode (put in the same table) but there is an initial stage and final stage.
In my opinion, a better solution for not reading the BLOB with the LINQ query would be to create a view on the table that contains all the column except for the BLOB ones.
You can then create an EF entity based on the view.
I have an oracle db which has no Foreign Keys, all table relations are handled by the software. For example, table Customer with columns Customer.customercode, Customer.Name where customercode is the primary key and table Order with columns Order.ordercode (PK), Order.customercode where customercode has no foreign key constraint. So far the application handles all transactions and takes care of all the table relations so that the data are consistent. I need to change this to a proper relational DB implementation, so I need to modify Order.customercode to be a FK from table Customer. Any sqlplus statement to do this without losing my data?
In Oracle, creating a foreign key would never lose any data, but it will fail if the data doesn't correspond to the new constraint. Assuming your data is OK, you can use an alter table statement:
ALTER TABLE order
ADD CONSTRAINT order_customer_fk FOREIGN KEY (customercode)
REFERENCES customer(customercode)