Foreign Key Table References Per Table (Max 253)
Feb 22, 2008
I've just found out about the concept that a table should only be references by foreign keys a maximum of 253 times throughout the database. I was hoping someone could give me a better idea of the dangers of disregarding this recommendation.
In our database, we have a Users table, which contains all of the users of a given system. In nearly every other table in our database, we have a field to indicate which user created the record. This is a reference back to the Users table. But as the number of tables has grown, we've surpassed that 253 limit. All I can tell, practically, is that I can no longer delete from the Users table. The query will fail, telling me the query optimizer ran out of memory, and that I should simplify my query.
The Users table is the only table that even comes close to this number of foreign key references. I don't even mind being unable to delete from the table. I'm mostly wondering if there are other problems with my design that will cause issues?
Is there a better way to keep track of who created a record in the database? Is it bad design to reference my Users table in so many places?
Thanks,
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May 15, 2008
Hey.
I'm trying to create some tables in my database but I'm getting some errors... The one which is causing the most trouble is Msg 1767, Level 16, State 0, Line 38
Foreign key 'ten_fk' references invalid table 'Tenant'.
I'm not sure why it's complaining... can anyone help me out here?
Cheers!
-- Mitch Curtis
-- A2create.sql
-- Set the active database to KWEA.
USE KWEA;
-- Drop existing tables (if any).
DROP TABLE Ownership;
DROP TABLE Tenant;
DROP TABLE Staff;
DROP TABLE Property;
DROP TABLE Property_Status_Report;
DROP TABLE Property_Owner;
DROP TABLE Placement_Record;
DROP TABLE Candidate_Tenant;
DROP TABLE Waiting_List;
-- Create new tables.
CREATE TABLE Waiting_List
(
waiting# INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
candidate_name VARCHAR(20) NOT NULL,
anticipated_start_date SMALLDATETIME NULL,
anticipated_end_date SMALLDATETIME NULL,
max_affordable_rent SMALLMONEY NOT NULL
);
CREATE TABLE Candidate_Tenant
(
candidate# INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
waiting# INT NULL,
name VARCHAR(20) NOT NULL,
phone_number INT NOT NULL,
required_property_type VARCHAR(10) NOT NULL,
CONSTRAINT w_fk FOREIGN KEY(waiting#) REFERENCES Waiting_List(waiting#)
);
CREATE TABLE Placement_Record
(
opening# INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
tenant# INT NOT NULL,
start_date SMALLDATETIME NOT NULL,
end_date SMALLDATETIME NOT NULL,
total_bonds SMALLMONEY NOT NULL,
weekly_rent SMALLMONEY NOT NULL,
CONSTRAINT ten_fk FOREIGN KEY(tenant#) REFERENCES Tenant(tenant#)
);
CREATE TABLE Property_Owner
(
owner# INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
name VARCHAR(20) NOT NULL,
phone_number INT NOT NULL
);
CREATE TABLE Property_Status_Report
(
address VARCHAR(30) NOT NULL,
report_date SMALLDATETIME NOT NULL,
weekly_rent SMALLMONEY NOT NULL,
month_rent_start_date SMALLDATETIME NOT NULL,
month_rent_end_date SMALLDATETIME NOT NULL,
maintenance_fee SMALLMONEY NOT NULL,
month_inspection_history VARCHAR(30) NULL,
CONSTRAINT ar_pk PRIMARY KEY(address, report_date),
FOREIGN KEY(address) REFERENCES Property(address)
);
CREATE TABLE Property
(
address VARCHAR(30) PRIMARY KEY NOT NULL,
staff# INT IDENTITY(1,1) NOT NULL,
type VARCHAR NOT NULL,
occupant_limit INT NOT NULL,
comments VARCHAR(30) NULL,
FOREIGN KEY(staff#) REFERENCES Staff(staff#)
);
CREATE TABLE Staff
(
staff# INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
manager# INT NOT NULL,
name VARCHAR(20) NOT NULL,
FOREIGN KEY(manager#) REFERENCES Staff(staff#)
);
CREATE TABLE Tenant
(
tenant# INT IDENTITY(1,1) PRIMARY KEY NOT NULL,
staff# INT NOT NULL,
property_address VARCHAR(30) NOT NULL,
name VARCHAR(20) NOT NULL,
phone_number INT NOT NULL,
street VARCHAR(20) NOT NULL,
city VARCHAR(20) NOT NULL,
postcode INT NOT NULL,
category VARCHAR(10) NOT NULL,
comments VARCHAR(30) NULL,
FOREIGN KEY(staff#) REFERENCES Staff(staff#),
FOREIGN KEY(property_address) REFERENCES Property(address)
);
CREATE TABLE Ownership
(
address VARCHAR(30) NOT NULL,
owner# INT NOT NULL,
CONSTRAINT ao_pk PRIMARY KEY(address, owner#),
FOREIGN KEY(address) REFERENCES Property(address),
FOREIGN KEY(owner#) REFERENCES Property_Owner(owner#)
);
-- Display tables.
SELECT * FROM Waiting_List;
SELECT * FROM Candidate_Tenant;
SELECT * FROM Placement_Record;
SELECT * FROM Property_Owner;
SELECT * FROM Property_Status_Report;
SELECT * FROM Property;
SELECT * FROM Staff;
SELECT * FROM Tenant;
SELECT * FROM Ownership;
Errors:
Msg 3701, Level 11, State 5, Line 8
Cannot drop the table 'Ownership', because it does not exist or you do not have permission.
Msg 3701, Level 11, State 5, Line 9
Cannot drop the table 'Tenant', because it does not exist or you do not have permission.
Msg 3701, Level 11, State 5, Line 10
Cannot drop the table 'Staff', because it does not exist or you do not have permission.
Msg 3701, Level 11, State 5, Line 11
Cannot drop the table 'Property', because it does not exist or you do not have permission.
Msg 3701, Level 11, State 5, Line 12
Cannot drop the table 'Property_Status_Report', because it does not exist or you do not have permission.
Msg 3701, Level 11, State 5, Line 13
Cannot drop the table 'Property_Owner', because it does not exist or you do not have permission.
Msg 3701, Level 11, State 5, Line 14
Cannot drop the table 'Placement_Record', because it does not exist or you do not have permission.
Msg 1767, Level 16, State 0, Line 38
Foreign key 'ten_fk' references invalid table 'Tenant'.
Msg 1750, Level 16, State 0, Line 38
Could not create constraint. See previous errors.
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Oct 23, 2004
Hello:
Need some serious help with this one...
Background:
Am working on completing an ORM that can not only handles CRUD actions -- but that can also updates the structure of a table transparently when the class defs change. Reason for this is that I can't get the SQL scripts that would work for updating a software on SqlServer to be portable to other DBMS systems. Doing it by code, rather than SQL batch has a chance of making cross-platform, updateable, software...
Anyway, because it needs to be cross-DBMS capable, the constraints are that the system used must work for the lowest common denominator....ie, a 'recipe' of steps that will work on all DBMS's.
The Problem:
There might be simpler ways to do this with SqlServer (all ears :-) - just in case I can't make it cross platform right now) but, with simplistic DBMS's (SqlLite, etc) there is no way to ALTER table once formed: one has to COPY the Table to a new TMP name, adding a Column in the process, then delete the original, then rename the TMP to the original name.
This appears possible in SqlServer too --...as long as there are no CASCADE operations.
Truncate table doesn't seem to be the solution, nor drop, as they all seem to trigger a Cascade delete in the Foreign Table.
So -- please correct me if I am wrong here -- it appears that the operations would be
along the lines of:
a) Remove the Foreign Key references
b) Copy the table structure, and make a new temp table, adding the column
c) Copy the data over
d) Add the FK relations, that used to be in the first table, to the new table
e) Delete the original
f) Done?
The questions are:
a) How does one alter a table to REMOVE the Foreign Key References part, if it has no 'name'.
b) Anyone know of a good clean way to get, and save these constraints to reapply them to the new table. Hopefully with some cross platform ADO.NET solution? GetSchema etc appears to me to be very dbms dependant?
c) ANY and all tips on things I might run into later that I have not mentioned, are also greatly appreciated.
Thanks!
Sky
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Feb 12, 2014
Is there any possibility to create a foreign key references more than one tables.
say for example,
Create table sample1(id int primary key)
Create table sample2(id int primary key)
Create table sample3(
id int primary key,
CONSTRAINT fk1 FOREIGN KEY REFERENCES sample1 (ID),CONSTRAINT fk1 FOREIGN KEY REFERENCES sample2 (ID))
this shows no error while creating, but in the data insertion it shows error..
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Apr 9, 2007
I want to create a table withmember id(primary key for Students,faculty and staff [Tables])and now i want to create issues[Tables] with foreign key as member idbut in references i could not able to pass on reference as orcondition for students, faculty and staff.Thank You,Chirag
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Oct 12, 2015
I have a database of 900+ tables with around 3000 SPs, and views. Manually I reviewed few tables and found that tables are not referenced with FK and I applied few. There are lots of tables and SPs using them in join statement, Is there any way with which I can get each tables missing references, any DMV or other manual script which tells about this?
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Nov 28, 2006
I want to make a query, stored procedure, or whatever which will only display the primary key where there does no exist a foreign key in linked table.For example. If I had two tables with a one to many relationship.A [Computer] has one or more [Hard Drives]. I want to select only those computers which do not have a Hard Drive(s) associated with them. That is, show all computers where the Computer_ID field in the [Hard Drives] table does not exist. This seems simple but I'm drawing a blank here.
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Jun 29, 2015
I need to delete records from a table (Table1) which has a foreign key column in a related table (Table2).
Table1 columns are: table1Id; Name. Table2 columns include Table2.table1Id which is the foreign key to Table1.
What is the syntax to delete records from Table1 using Table1.Name='some name' and remove any records in Table2 that have Table2.table1Id equal to Table1.table1Id?
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Jun 21, 2015
Previously same records exists in table having primary key and table having foreign key . we have faced 7 records were lost from primary key table but same record exists in foreign key table.
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Aug 23, 2006
Here is my issue I am new to 2005 sql server, and am trying to take my old data which is exported to a txt file and import it to tables in sql. The older database is non relational, and I had made several exports for the way I want to build my tables. I built my packages fine and everything is working until I start building relationships. I remove my foreign key and the table with the primary key will get updated for the package again. I need to update the data daily into sql, and once in it will only be update from the package until the database is moved over.
It will run and update with a primary key until I add a foreign key to another database.
Here is my error when running the package when table 2 has a foreign key.
[Execute SQL Task] Error: Executing the query "TRUNCATE TABLE [consumer].[dbo].[Client] " failed with the following error: "Cannot truncate table 'consumer.dbo.Client' because it is being referenced by a FOREIGN KEY constraint.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly.
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Feb 3, 2015
Is there any way to enforce table references in stored procedures? For Example, we have stored procedures with a ton of different formats, "dbo.table", "table", "db.dbo.table", etc. Can we make it so that for every stored procedure, the reference must be at least "dbo.table"?
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Feb 12, 2007
mahesh writes "HI,
I am new to sql server.
can anybody help me
I have a table named tblqualificationmaster.
can i know the foreignkeys and the table related to this
tblqualificationmaster having foeign keys using stored procedure."
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Oct 7, 2014
I got the following problem to solve in TSQL. I don't want to use a cursor. But with the set based solution I am stuck.
Here is my problem:
DECLARE @tmp TABLE (CustomerID INT, CustomerLink INT, PRIMARY KEY(CustomerID))
INSERT @tmp
VALUES(100001,0)
,(100002,100001)
,(100003,100001)
,(100004,100003)
,(100005,100006)
[Code] ....
Desired result:
[CustomerID of a group member],[smallest CustomerID per Group]
|(GroupID)|CustomerID|CustomerLink|
|100001 |100001 |100001 |
|100001 |100002 |100001 |
|100001 |100003 |100001 |
|100001 |100004 |100001 |
|100005 |100005 |100005 |
[Code] .....
doesn't work for crossreferences :.(
RESULTSET:
CustomerID CustomerLink
100001 100001
100002 100001
100003 100001
100004 100001
100005 100005
100006 100006 --wrong
[Code] .....
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Sep 13, 2006
Ok, I'm really new at this, but I am looking for a way to automatically insert new records into tables. I have one primary table with a primary key id that is automatically generated on insert and 3 other tables that have foreign keys pointing to the primary key. Is there a way to automatically create new records in the foreign tables that will have the new id? Would this be a job for a trigger, stored procedure? I admit I haven't studied up on those yet--I am learning things as I need them. Thanks.
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Apr 27, 2008
it is attributed ?
Hi everyone,
My table contains columns that are goreign keys to other tables. How can i tell to which table/column each fk is attributed ?
Thanks
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Apr 11, 2008
For this example suppose than we a have a DB in SQL Server 2000 with the tables Client, Orders and DetailOrders. the field for each one are:
Client: id_Cliente, Name_client
Orders: id_Order, fk_client, date
DetailOrders: id_Detail, fk_Order, Product
Between all this tables exist one or more foreign key restriction but I don't know them. However I know than exist a row in the SYSOBJECTS (system table) per each one of the foreing key restriction, using this information I want to build a query than back to me something like this:
Type Table1 Field1 Table2 Field2
--------------------------------------------------------------------------------------------------------
FK Orders fk_Client Clients id_Client
FK DetailOrders fk_Order Orders id_OrderFK
Somebody can tell me hoy can i do it?
tks 4 help.
Leo.
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Nov 30, 2006
I was thinking of adding tables to ASPNetDB.mdf and have one of those tables have column userid as a foreign key from aspnet_Users
When I try to create relationship in Diagram, I get error saying that "data typ properties does not match"
userid in aspNet_Users is uniqueidentifier and userid (fk) in new table is int
What should I use, should I do that at all?
Thanks
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Aug 25, 2007
Hi how do i to delete a table with a foreign key?
When i try to delete the table i get error 3726
any?
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Jun 9, 2008
hi all
can we assign two foreign key to one table .
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Dec 27, 2013
I have created two tables in phpMyAdmin 3.5.8.1. comments which stores comments users post on a website and registration which stores a users registration details (username, password, e-mail etc, etc).
I want to add the username field from the registration table as a foreign key to the comments table. How do I do this in phpMyAdmin?
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Dec 19, 2007
use default pubs database in sqlserver2000.
use authors table and publishers table.
Write a query to list first name, last of all authors
and name of the publisher (if any) present in the same city
as the author. If no publisher is present in the city
where the author is located then the column should contain a
NULL value. If there is more than one publisher in the city
where the author is located, then the details of
the author are to be repeated for each publisher.
but there is no field match between authors table and publishers table.
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Jun 13, 2006
There is itemlookup table, which stores item number and itemdescription. Also there is a child table, pricehistory, of theitemlookup table, which stores different prices and different dateranges. So it is one-to-many relationship. (Price can be stored morethan one with a different date range)And there is another table RequestItem that stores the foreign key ofthe itemlookup table to show the information of the itemlookup table.Then how do I know later which date range of the price was stored inthe RequestItem table? Since I only keep the foreign key of theitemlookup table, it will be impossible to keep track of the row of thepricehistory table if there are more than one data existed in thepricehistory table.Will it be a valid table structure to create a column for the foreignkey of the pricehistory in RequestItem table or any other ways tohandle this issue?
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Sep 27, 2006
Hi,
I have a datatable with the following values:
ID
CompanyID
CompanyName.
Here ID is the foreign key. I was wondering if there was a way to update tables with foreign keys. Searching for stuff gave me something like update cascade. Can somebody please elaborate on that?
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Apr 4, 2008
Newbie question. Can someone show me an SQL statement that sorts the results of a query by a field in a different table?
CREATE TABLE `Table1`
(
`table1_id` INTEGER AUTO_INCREMENT ,
`table1_name` VARCHAR(255),
PRIMARY KEY (`table1_id`)
)
CREATE TABLE `Table2`
(
`table2_id` INTEGER AUTO_INCREMENT ,
`table2_name` VARCHAR(255),
`table2_table1` INTEGER,
PRIMARY KEY (`table2_id`)
)
ALTER TABLE `Table2` ADD FOREIGN KEY (`table2_table1`) REFERENCES `Table1`(`table1_id`);
What I'd like is something like:
SELECT * FROM Table2 ORDER BY "Table1(table2_table1).tabel1_name",table2_name
It's the section in double quotes that I can't figure out how to compose.
As an example, if Table 1 has
1, A
2, B
3, C
and Table 2 has
1, a, 2
2, b, 1
3, c, 2
then I'd like the sort to return
2, b, 1
1, a, 2
3, c, 2
TIA,
Stephen
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Aug 16, 2004
I have two tables as below. I want to update a quote and change the item for which it is for. So I want to do an update statement to change the cat_ref that the quote is for. However, when I do this I get a foreign key conflict with cat_ref in the item table. How do I get around this? Thanks
Code:
CREATE TABLE Item (
cat_ref VARCHAR(5)PRIMARY KEY,
descrip VARCHAR(50),
date_added SMALLDATETIME,
cat_type VARCHAR(20))
CREATE TABLE has_quote (
quote_id INT IDENTITY (1,1) PRIMARY KEY,
date_last_pricecheck SMALLDATETIME,
cat_ref VARCHAR(5)FOREIGN KEY
REFERENCES Item(cat_ref)
ON DELETE CASCADE,
first_name VARCHAR(10),
surname VARCHAR(10),
FOREIGN KEY (first_name, surname)
REFERENCES Customer(first_name, surname)
ON DELETE CASCADE
ON UPDATE CASCADE)
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May 30, 2007
How do I create a table with a foreign key
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Apr 19, 2008
Hi,
We're having a few linked servers in our company. some tables in one of the linked servers include columns (better saying, foreign keys) of tables in another server. I wonder if there's a way to create a foreign key referencing one column in another server. That is, suppose there's Column A in table A in Server A which references Column B in table B in server B, is there a way to create column A as foreign key referencing column B?
Any idea is appreciated.
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Apr 19, 2008
Hi,
We're having a few linked servers in our company. some tables in one of the linked servers include columns (better saying, foreign keys) of tables in another server. I wonder if there's a way to create a foreign key referencing one columns in another server. That is, suppose there's Column A in table A in Server A which references Column B in table B in server B, is there a way to create column A as foreign key referencing column B?
Any idea is appreciated.
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May 1, 2007
I'm using SQL Server 2000. I have an EXTERNAL_FUNDING table and an EXTERNAL_FUNDING_TYPE table. The DDL for the tables is listed below. Each EXTERNAL_FUNDING record has a type field, which is a foreign key to a record in the EXTERNAL_FUNDING_TYPE table. However, I would like for the type to be allowed to be null. When displaying the data, if the type is null, I'd like to show blank text. Here is the query I'm trying to use:
SELECT EXTERNAL_FUNDING.id, date_requested as [Request Date],source as [Source/Sponsor],EXTERNAL_FUNDING_TYPE.type AS [Type],amount as [Amount], granted as [Granted]
FROM EXTERNAL_FUNDING,EXTERNAL_FUNDING_TYPE
WHERE (project_id = @project_id) AND
(EXTERNAL_FUNDING.type = EXTERNAL_FUNDING_TYPE.id)
ORDER BY date_requested ,source,type
But this query does not return the records with NULL for the type field. Can someone explain to me how I can also return the rows with a NULL type? Thanks!
Table DDL:
CREATE TABLE [dbo].[EXTERNAL_FUNDING] (
[id] [int] IDENTITY (1, 1) NOT NULL ,
[project_id] [int] NOT NULL ,
[date_requested] [datetime] NULL ,
[source] [nvarchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,
[type] [int] NULL ,
[amount] [money] NULL ,
[granted] [bit] NULL ,
[date_granted] [datetime] NULL
) ON [PRIMARY]
CREATE TABLE [dbo].[EXTERNAL_FUNDING_TYPE] (
[type] [nvarchar] (30) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL ,
[id] [int] IDENTITY (1, 1) NOT NULL
) ON [PRIMARY]
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Aug 31, 2005
HiI am creating new SQL Server Tables using SQL Server 2005. I have setprimary key to the tables .But I do not know how to assign Foreign keyto the tables .I need to do some joins later and that is why I have toput Foreign key to the table . The Primary key is visible and can beassigned easily .But How do I assign foreign key .Thanks*** Sent via Developersdex http://www.developersdex.com ***
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Feb 5, 2008
Hello,
I have a very elementary question on table design. This screenshot (which is part of a larger diagram) sets the context of the question.
There are two distinct groups of products with different attributes, hence two separate tables: Products_A and Products_B.
There's a third table that keeps track of daily production (DailyProduction), which must accept items from either product table. Now, my question is: How do I relate these two tables to "DailyProduction" ? If I place a double-constraint with two foreign keys, then I get an error whenever I attempt to insert a record in DailyProduction. For example, if the new item is of "Products_A" type, then the error message from SSMS is:
No row was updated.
The data in row 1 was not committed.
Error Source: .Net SqlClient Data Provider.
Error Message: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_DailyProduction_Products_B". The conflict occurred in database "MyDatabase", table "dbo.Products_B", column 'ProductB_ID'.
The statement has been terminated.
Correct the errors and retry or press ESC to cancel the change(s).
It's clear that the error message makes sense as SQL is trying to apply BOTH constraints. It's one AND the other, not one OR the other. Now, how do I remedy this ? What would be the most appropriate way to relate the three tables ?
Thanks.
Fernando
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Nov 10, 2006
Hi
I am trying to update tables "Table A" & " TableB" with a new value for a particular column1. Now "TableA" contains a foreign key "FK1" defined on it and is referencing another table "Table B" containing the similar column "Column1"
Because of this constraint I was not able to update TableA and TableB. My question is
1) If i wanted to go ahead with this update, what are the possible ways?
2) If only solution is to drop the constraint. Then How do i know the definition for this particular Foreign key, i mean it may refer some columns in Table B. I wanted to know the complete definition of it so that i can rebuild the constraint after the update. Right now i can see only the constraint name when i use sp_help TableA. But how do i know the complete reference made by this foreign key.
Early reply is much appreciated
Thanks!
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Sep 2, 2015
I am seeing untrusted foreign key in one of my tables in a dev environment. To fix it I tried to run
ALTER TABLE [dbo].[TableName] WITH CHECK CHECK CONSTRAINT [ForeignKey]
But I am getting the below error
The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "foreignkey". The conflict occurred in database " DBname", table "dbo.tablename", column 'columnname'.
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