Hi All,
I know that when you specify a PRIMARY KEY or UNIQUE constraint for a table, SQL Server creates a unique index for the primary key columns.
What about foreign keys? Does SQL Server creates an index when you create a foreign key?
I have looked in Books Online and on the Internet, but couldn't find any information.
Thanks in advance.
Hi All,
I know that when you specify a PRIMARY KEY or UNIQUE constraint for a table, SQL Server creates a unique index for the primary key columns.
What about foreign keys? Does SQL Server creates an index when you create a foreign key?
I have looked in Books Online and on the Internet, but couldn't find any information.
Thanks in advance.
I know this is probably a flick of a switch but I cannot figure out which switch. Setup is SQL Server / Stored Procedures / DAL / BLL(skipped for testing) / PL. The stored procedure queries from only one table and two columns are ignored because they are being phased out. I can run the stored procedure and preview the data in the DAL but when I create a page with an ODS linked to the DAL and a GridView I get this error. I checked every column that does not allow nulls and they all have values. I checked unique columns (ID is the only unique and is Identity=Yes in the table definition). I checked foreign-key columns for values that are not in the foreign table and there are none. Any ideas why do I get this?
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
Hi,
I am getting the above error when trying to load a report into my Web Application, I have tracked the error down to one specific field in my database. Even though this field is a NVarChar field and is of size 30 it would seem that there is an issue returning the value from the field. I can write it into the database no problems but when I try to get it out of the database it returns the above error.
e.g
MOB 401.908.804 - Fails
0401.907.324 - okay
8239 9082 (pager) - fails
Anyone got an idea on how to fix this????
Regards..
Peter.
I have two tables, T1 and T2.T1 has a foreign Key that refers to a key in T2.The way that I see it, its only possible to insert something into T1 ifthere already exists a tuple in T2 with the same value in key.That means that I always have to insert something into T2 before insertinginto T1Is that correct?
View 1 Replies View RelatedI have a situation where attending a meeting could be either staff orcoalition members. But don't know how to enforce a foreign keyconstraint. any ideas ?Table MeetingMeetingID int NOT NULL,AttendeeID int NOT NULLPrimary Key (MeetingID, AttendeeID)Table StaffStaffID int IDENTITY not null PRIMARY KEYTable CoalitionMemberMemberID int Identity not null PRIMARY KEYSince AttendeeID can either a value from Staff.StaffID or fromCoalitionMember.MemberID, I cannot place both constraints asADD CONSTRAINT [FK_Meeting_Staff] FOREIGN KEY(AttendeeID)REFERENCES [Staff] ([StaffID])ADD CONSTRAINT [FK_Meeting_CoalitionMember] FOREIGN KEY(AttendeeID)REFERENCES [CoalitionMember] ([MemberID])
View 1 Replies View RelatedWhen following a script to create some tables and constraints, it is recommended that you name the FK constraint? Otherwise it appears with numbers after it. Is this the way 2005 creates them or has this always been the naming convention?
kat
When I first set up my database, I set it up with many unique constraints, but not much in the way if indexes. After reading more about the benefits of indexes, I'm thinking of deleting many of the unique constraints, and replacing them with unique indexes where appropriate.
It seems that indexes would be better than unique constraints in many cases, because you have the double benefit of enforcing uniqueness, as well as improving sorting capability. Does this make sense?
What is the difference between creating a Unique Constraint and Unique Index? How does creating Index/Constraint affect my performance and db size?
Thank you.
I want to disable foreign key constraints en mass. Is there a way to do this?
I know that I can go into each table and navigate to the Relationship tab of Properties and uncheck the "Enforce relationship for INSERTs and UPDATEs" box, but I'd much prefer to automate this process with a query since there are 160+ tables and probably 200+ relationships to disable.
I figure that sysconstraints my be the ticket, but I will keep experimenting until I get the right solution. In the meantime, any insight to steer me in the right direction is appreciated.
I've recently implemented a whole bunch of foreign key constraints in a database. As a result I have issues every time I want to truncate a table to perform data loads.
Is there an easy way to tell the system to ignore these constraints for the term of a data load or truncation of data?
thank you
I have recently restored an SQL Server 2000 database on SQL Server 2005
A number of constraints on the database had previously been disabled
A monthly process that is carried out, imports data into 'Table A'.
This process now crashed, being unable to truncate table as it referenced by 'Table B'
Although when i check the properties of the constraint the 'enforce foreign key constraints' is set to no.
Is there a known issue with restoring databases on 2005,
Any help greatly appreciated.
Micheal
I have a table that I want to run an UPDATE statement to change some data in the table, but I get this error:
Server: Msg 547, Level 16, State 1, Line 1
UPDATE statement conflicted with COLUMN FOREIGN KEY constraint 'FK__Yield__Financial_Product__ProductCode'. The conflict occurred in database 'lsmdb', table 'Financial_Product', column 'ProductCode'.
The statement has been terminated.
How do I update the ProductCode column in both tables to reflect my updated data?
Thanks in advance.
CREATE TABLE IssueLog (
ItemNo int NOT NULL IDENTITY PRIMARY KEY
REFERENCES IssueProgress (ItemNo)
ON UPDATE CASCADE
ON DELETE CASCADE,
REFERENCES Approvals(ItemNo)
ON UPDATE CASCADE
ON DELETE SET NULL,
Msg 142, Level 15, State 2, Line 0
Incorrect syntax for definition of the 'TABLE' constraint.
I'd like to update or delete the IssueProgress plus update and setting null to the Approvals tables at the same time whenever the ItemNo of the parent table namely IssueLog is updated or deleted.
How can I achieve this?
How can I get and or set the order in which the cascading deletes of a table are executed??
I have table A with cascading deletes to Table B and Table C. Records in table B can not be deleted if they are referenced from table C. So if I delete C, then B and then A; that would work. But B then C and then A might be prohibited due to the constraint between B and C. Therefor the order of execution of the cascading delete is important.
I want to replicate the foreign keys to secondary.I changed the value Copy foreign key constraints value is to True.
I changed this value at pub properties - Articles -
And then it is asking for MARK for reinitialization with the new snapshot.I clicked ok.
When I checked sync status it has given the message like initial snapshot is not yet available.I started the snapshot and the subscription started replication records.When check at pup properties the value Copy foreign key constraints again false.
After changing the value to true it is showing as False.
Ok, so I've broken down and decided to write myself an invoicing
program. I'd like to use GUID fields as the Primary Keys in my
table. Now, I basicly bill for two seperate items:
Deliverables and Services.
So, my Layout's gonna look something like
Create Table Invoice(
ID UniqueIdentifier Primary Key,
-- Other Data
);
Create Deliverable(
ID uniqueidentifier Primary Key,
ParentInvoice uniqueidentifier,
-- Other data);
--...
Im sure there are probems with that as it's written feel free to edify me as to what they are.
my questions are such:
1) Does a uniqueidentifier field automagically get a value?
2) If not how do I generate one in TSQL?
3) If so, what do I use to store my Foreign Keys.
4) How do I declare my Foreign key constraints?
Guys,
I have 600 tables in my database, out of which 40 tables are look up value tables. I want generate truncate scripts which truncates all the tables in order of Parent child relationship excluding lookup tables. Is there any way to do this apart from figuring out Parent Child relationship and then writing the truncate statements for each of the table.
For example
EmployeeDetail table references Employee table
DepartmentDetail table references Department table
Department table references Employee table
My truncate script should be
TRUNCATE TABLE DEPARTMENTDETAIL
TRUNCATE TABLE EMPLOYEEDETAIL
TRUNCATE TABLE DEPARTMENT
TRUNCATE TABLE EMPLOYEE
Is there any automated way to figure out parent and child tables and generate truncate script for the same.
Thanks
I am testing Insert, Update etc. and messing up my database with "dirty" data. Is there a way to temporarily drop FOREIGN KEY constraints to truncate a table after testing without dropping the whole table and rebuilding it?
Newbie
Hello,
A quick question concerning foreign keys. I have been creating a database using the database diagram view in sql server management studio, and have an issue when creating foreign key relationships. When I specify a relationship in this view I imagine what is created is simply a constraint between a unique field in one table and the a foreign key in another. My issue is, is it better to index all foreign keys? If this is the case, is there a way to automate this so I don't have to manually create an index for every foreign key?
Thanks,
Mike
I'm working on creating a new version of an existing table. I want to keep the old table around, only with a different name. In looking this up I found there's a system routine named sp_rename, which looks like it will work fine.However in thinking about this I realized that the foreign key constraints defined on the table (there's 3 of them) are likely to not be renamed, correct?
If I'm correct, then I suppose I could rename the table, then drop the 3 foreign key constraints, and create them new using different names for those foreign key constraints.
How to copy a table from one server to another server with primary and foreign key constraints.
View 5 Replies View RelatedHow to delete records from multiple tables if main table’s entity is deleted as constraints is applied on all..There is this main table called Organization or TblOrganization.and this organization have branches which are in Brach table called tblBranch and this branch have multiple applications let say tblApplication and these application are used by multiple users called tblUsers.What I want is: when I delete the Organization All branches, application and users related to it must be deleted also.How I can apply that on a button click in asp.net web forms..Right now this is my delete function which is very simple
Public void Delete(int? id){
var str=”DELETE FROM tblOrganization WHERE organizationId=”+ id ;
}
And My tables LOOK LIKE this
CREATE TABLE tblOrganization
(
OrganizationId int,
OrganizationName varchar(255)
[code]...
If i create a simple table with a foreign key constraint, does itcreate an implicit index on that given ID? I've been told this isdone in some databases, but i need to know for sure if SQL Server doesit. Has anyone heard of this before, on any other databses perhaps?Heres an example of how the foreign key constraint is being added:ALTER TABLE [dbo].[administrators] WITH CHECK ADD CONSTRAINT[FPSLUFSUOXZGAJOJ] FOREIGN KEY([AdministratorRoleID])REFERENCES [dbo].[administratorroles] ([AdministratorRoleID])My initial testing seems to indicate adding an index on the foreignkey column helps, but i need to know for sure. Any insight would begreatly appreciated!Bob
View 6 Replies View Relatedwhat the best practice is for creating indexes on columns that are foreign keys to the primary keys of other tables. For example:
[Schools] [Students]
---------------- -----------------
| SchoolId PK|<-. | StudentId PK|
| SchoolName | '--| SchoolId |
---------------- | StudentName |
-----------------
The foreign key above is as:
ALTER TABLE [Students] WITH CHECK ADD CONSTRAINT [FK_Students_Schools]
FOREIGN KEY([SchoolId]) REFERENCES [Schools] ([SchoolId])
What kind of index would ensure best performance for INSERTs/UPDATEs, so that SQL Server can most efficiently check the FK constraints? Would it be simply:
CREATE INDEX IX_Students_SchlId ON Students (SchoolId)
Or
CREATE INDEX IX_Students_SchlId ON Students (SchoolId, StudentId)
In other words, what's best practice for adding an index which best supports a Foreign Key constraint?
Hi,
How can I copy a database table with all its data, indexes and constraints to a new table in the same database in sql server 2005
I'm working to improve performance on a database I've inherited, and there are several thousand indexes. I've got a list of ones which should definitely exist within the database, and I'm looking to strip out all the others and start fresh, though this list is still quite large (1000 or so).
Is there a way I can remove all the indexes that are not in my list without too much trouble? I.e. without having to manually go through them all individually. The list is currently in a csv file.
I'm looking to either automate the removal of indexes not in the list, or possibly to generate the Create statements for the indexes on the list and simply remove all indexes and then run these statements.
As an aside, when trying to list all indexes in the database, I've found various scripts to do this, but found they all seem to produce differing results. What is the best script to list all indexes?
So I'm reading http://www.sql-server-performance.com/tips/clustered_indexes_p2.aspx and I come across this:
When selecting a column to base your clustered index on, try to avoid columns that are frequently updated. Every time that a column used for a clustered index is modified, all of the non-clustered indexes must also be updated, creating additional overhead. [6.5, 7.0, 2000, 2005] Updated 3-5-2004
Does this mean if I have say a table called Item with a clustered index on a column in it called itemaddeddate, and several non-clustered indexes associated with that table, that if a record gets modified and it's itemaddeddate value changes, that ALL my indexes on that table will get rebuilt? Or is it referring to the table structure changing?
If so does this "pseudocode" example also cause this to occur:
sqlstring="select * from item where itemid=12345"
rs.open sqlstring, etc, etc, etc
rs.Fields("ItemName")="My New Item Name"
rs.Fields("ItemPrice")=1.00
rs.Update
Note I didn't explicitly change the value of rs.fields("ItemAddedDate")...does rs.Fields("ItemAddedDate")=rs.Fields("ItemAddedDate") occur implicitly, which would force the rebuild of all the non-clustered indexes?
I have a requirement to only rebuild the Clustered Indexes in the table ignoring the non clustered indexes as those are taken care of by the Clustered indexes.
In order to do that, I have taken the records based on the fragmentation %.
But unable to come up with a logic to only consider rebuilding the clustered indexes in the table.
create table #fragmentation
(
FragIndexId BigInt Identity(1,1),
--IDENTITY(int, 1, 1) AS FragIndexId,
DBNAME nvarchar(4000),
TableName nvarchar(4000),
[Code] ....
What is the difference please?
View 1 Replies View RelatedI'm using MS SQL 2000 with enterprise manager I have a customers table called high_customer, it has a primary key called IDI have an invoices table called high_invoices, it has no primary keys but it does have a column for customer ID.I want to set it so if a customer is deleted from the customers table, any invoices with that customerID are deleted from the invoices table.Do I need to specify a constraint? If so how do I do it in enterprise manager.Thanks
View 1 Replies View RelatedHi,
I have the following problem:
I have a table called Jobs with the fields:
JobNumber, Name, Customer, ...
And a table called Customers with the fields:
ID, Name, Address, ...
Obviously Jobs is linked to Customers with the Customer<->ID fields. I want to set it up so that if a Customer is deleted, then any Jobs that had that customer listed now have the Customer field set to NULL. Can I do this with a constraint, or will I need to use a trigger?
Cheers,Little'un
Hello,
I am not a DBA and I need to do the following.
I have 2 tables A and C and both have a common fileds say emp.Emp is pkey in C .
There can be a record in C but not in A.If a record is inserted in A then it checks for the same employee info in C .If not found it do not allow to insert a record in A.
How to go for it?
Thanks!