I'm not sure about the way you enforce the referential integrity in a SQL server 6.5 database (I'm new to this environment). Does any one have an exemple. The doc I have is useless...Thanks
View 1 RepliesHi,
I need to write a referential integrity trigger. I have two tables called Table1 and Table2. In both the tables i have common column called FieldA.
Now i need to write a trigger, whenever i updates Table1 this trigger automatically needs to update a FieldA in Table2.
Can anyone give me Code or suggestions , how to write this trigger. I am new to triggers.
Thank you!
---Ram
Hi,
I need to write a referential integrity trigger. I have two tables called Table1 and Table2. In both the tables i have common column called FieldA.
Now i need to write a trigger, whenever i updates Table1 this trigger automatically needs to update a FieldA in Table2.
Can anyone give me Code or suggestions , how to write this trigger. I am new to triggers.
Thank you!
I know how to write a normal insert , update, delete triggers and using help from books online.. SO pls do it in useful.
---Ram
Using the new referential integrity constraints that will be made available, will it allow us to manually define the relationships between entities even if there is no true foreign key constraints setup in the database?
Lets say we deleted the FK_Orders_Customers in Northwind between orders and customers.
Or is this ability available now?
Thank for your time.
I am having great difficulty with cascading deletes, delete triggers and referential integrity.
The database is in First Normal Form.
I have some tables that are child tables with two foreign keyes to two different parent tables, for example:
Table A
/
Table B Table C
/
Table D
So if I try to turn on cascading deletes for A/B, A/C, B/D and C/D relationships, I get an error that I cannot have cascading delete because it would create multiple cascade paths. I do understand why this is happening. If I delete a row in Table A, I want it to delete child rows in Table B and table C, and then child rows in table D as well. But if I delete a row in Table C, I want it to delete child rows in Table D, and if I delete a row in Table B, I want it to also delete child rows in Table D.
SQL sees this as cyclical, because if I delete a row in table A, both table B and table C would try to delete their child rows in table D.
Ok, so I thought, no biggie, I'll just use delete triggers. So I created delete triggers that will delete child rows in table B and table C when deleting a row in table A. Then I created triggers in both Table B and Table C that would delete child rows in Table D.
When I try to delete a row in table A, B or C, I get the error "Delete Statement Conflicted with COLUMN REFERENCE". This does not make sense to me, can anyone explain? I have a trigger in place that should be deleting the child rows before it attempts to delete the parent row...isn't that the whole point of delete triggers?????
This is an example of my delete trigger:
CREATE TRIGGER [DeleteA] ON A
FOR DELETE
AS
Delete from B where MeetingID = ID;
Delete from C where MeetingID = ID;
And then Table B and C both have delete triggers to delete child rows in table D. But it never gets to that point, none of the triggers execute because the above error happens first.
So if I then go into the relationships, and deselect the option for "Enforce relationship for INSERTs and UPDATEs" these triggers all work just fine. Only problem is that now I have no referential integrity and I can simply create unrestrained child rows that do not reference actual foreign keys in the parent table.
So the question is, how do I maintain referential integrity and also have the database delete child rows, keeping in mind that the cascading deletes will not work because of the multiple cascade paths (which are certainly required).
Hope this makes sense...
Thanks,
Josh
Question:
What is used to enforce referential integrity ?
Answer: Triggers; Foriegn Keys.
what is Foreign Keys ?
How do you enforce referential integrity in SQL between tables?
Thanks.
I used to work with little databases and throw everything into a table with no relation, and modify them all individually. Now I've learned about referential integrity, makes things a lot easier.
My question is, now what? Say I have a Customers table and an Orders table (to keep it simple). If custID is the primary key in customers, foreign key in orders, then if I want to insert into Orders, I need the custID. So those kinds of things I need to keep stored in a session state and insert them like that, correct?
Hi guys,
Is there a way of finding the foreign keys for a table and therefore determine weather any referential integrity rules would be broken if a record was deleted?
For example. You have an author you want to delete, but that author has books. You call a procedure to delete the author. The stored procedure checks the foriegn keys, checks the tables and determines what is in them and if any tables have records that would be "orphaned" you return an error reporting what tables have the "would be orphaned" data in them.
It need to be fairly generic int he manner that it checks the foreign keys and the sub table data.
This is on behalf of a guy at work so "requirements" may change. ;)
Anyone got some ideas??
Cheers,
Shaun
hi guys,
i was asked to drop some tables...but before dropping i was asked to check for referential integrity..
so where and how can i check this referential integrity????
Hihow to set the referential integrity between 2 tables using enterprisemanager (microsoft SQL SERVER).. i tried and the tab doesn't allow meto choose. pls.help.thankssree--chavasreedharMessage posted via http://www.exforsys.com for all your training needs.
View 1 Replies View RelatedWhat ate the method/techniques i can use for enforcing referential integrity, Without using foreign key constraints ?
View 7 Replies View RelatedI'm using Microsoft SQL Server Management Studio Express 9.00.2047.00and expriencing problems with setting referential integrity on a linktable. The tables' schema is as follows:-------------------------------------------------------------------CREATE TABLE competencies (CID bigint identity(1,1) CONSTRAINT pk_CID PRIMARY KEY,LockedBy bigint DEFAULT 0 NOT NULLCONSTRAINT fk_UserIDREFERENCES usr_info(userID)ON DELETE SET DEFAULTON UPDATE CASCADE)---------------------------------------------------------CREATE TABLE usr_info (userID bigint IDENTITY(0,1) CONSTRAINT pk_UID PRIMARY KEY,ActiveFlag bit default 0 NOT NULL, --(1='Yes', 0='No')FirstName varchar(100) default '' NOT NULL,LastName varchar(100) default '' NOT NULL)-------------------------------------------------------CREATE TABLE competency_hdr (fkCID bigint default 0 NOT NULLCONSTRAINT fkCID_chREFERENCES competencies(CID)ON DELETE CASCADEON UPDATE CASCADE,ApprovedBy bigint default 0 NOT NULLCONSTRAINT fkUserID_chREFERENCES usr_info(userID)ON DELETE SET DEFAULT -- NO delete if user is deletedON UPDATE CASCADE)--------------------------------------------------------When I execute the above I get the following error message.Msg 1785, Level 16, State 0, Line 1Introducing FOREIGN KEY constraint 'fkUserID_ch' on table'competency_hdr' may cause cycles or multiple cascade paths. SpecifyON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGNKEY constraints.Msg 1750, Level 16, State 0, Line 1Could not create constraint. See previous errors.Now, if i swap the fields around then the error message changes tothat of the fkCID field.Basically what I want is:when I delete a competency record I need all references to this recordto be deleted.when I delete a user I want to set the foreign key to zero (the recordmust remain on the database).Obviously there is something I'm missing here. Any advice, anyone?---------------------------------------------------------------Join Bytes! : Remove your pants to reply---------------------------------------------------------------
View 6 Replies View RelatedHow I do, in SQL SERVER 7.0, referential integrity (Foreign Key constraints) between tables storaged in differents databases?.
Thank for any help.
Hi All,
I am inserting into a table that hold several foreign keys from several tables.
I'm performing this via a client (VB) and I only how to capture the error, but unable to determine which column/field is the one that violates referential integrity.
Any one can shed some light here? Many thanks!
Cyherus
I have a lookup table called States, I have multiple other tables that use this lookup table, but I can only relate to one other table. My question is if I change a state name how do I enforce that change to the other tables that CANT be related? I know it is a design flaw and need some kind of joining table. I am having difficulty understanding and incorporating first normal form in my database. Here is what i have so far.
Example:
Table 1
========|============|=============|========|
CustomerID BillingAddressID ShippingAddressID OtherFields
========|============|=============|========|
Table 2
===========|======|========|
BillingAddressID StateID OtherFields
===========|======|========|
Table 3
=============|======|========|
ShippingAddressID StateID OtherFields
=============|======|========|
Table 4
======|====|
StateID Name
======|====|
How do I relate table 4 with table 2 & 3 for referential integrity? Or create a joiner table?
hi there!
im having problems deleting rows in a reference table. is there any tools which tables to delete first before deleting the rows in the table which contains the primary key?
i have a lot of tables let say over 300 so its hard for me to guess which comes first... what should i keep in mind deleting rows with a referential integrity?
thank...
Two ways to do this... Creating the constraints when creating the data model OR using SQL to use the 'reference' constraint. Does 2005 provide any other automated method of creating the Primary Key - to Foreign key constraints without writing the SQL to do this?
Thx
Hello Everyone.
I'm trying to set a procedural referential integrity on a table, files, which references to table users (a file is created by a user but one user can have more than one file).
Here, given that I can't create a referential integrity ON DELETE SET NULL (the reason il long to explain so just don't care about it), I would like to emulate the RI with a trigger.
On deleting a user the files associated to him have their IDUser set to null.
I have a problem, this is the trigger:
CREATE TRIGGER PRI_FilesOnUsers
ON Files
INSTEAD OF DELETE
AS
-- When a user is deleted the files must have no user associated, set IDUser to null
UPDATE Files
SET IDUser = NULL
WHERE IDUser = ?????????????????????????????????????????????????????
GO
WELL what do I heve to put there, how can i retrieve the values of the fields of the record that the user tried to delete?????Help me thanks
Hi,
How could I define referential integrity using FK constraint which allow me to have empty string/ZERO number instead of NULL value ?
Thank you
I'm designing a database to store information about jobs that are in progress at a property. More than one job can be in progress at a property at one time and each different kind of job can contain different data, although they all share some common fields such as StartDate.
So I have a table that stores the property details PropertyDetails:
*ID
PropertyAddress
PropertyPostCode
Then I have a table that stores all of the jobs' shared details:
*PropertyID
*JobID - These three make up a compound primary key
*JobType
StartDate
EndDate
Then I have individual tables for each of the Jobs, for example BuildingWork:
*JobID
BuildingContractor
InsuranceCompany
Which works great, and enables me to query all basic job details from one table (JobDetails) rather than multiple tables for every job type.
BUT: I don't know how to enforce the referential integrity of the database. Obviously I can use a constraint to cascade deletes from the PropertyDetails table to the JobDetails table through the PropertyID, but there doesn't appear to then cascade the deletes from the JobDetails table to the individual Job tables as JobDetails has no idea what tables are there.
If I store the relevant individual table name as the JobType in the JobDetails table, could I use a trigger to somehow delete the related record from that table?
Littlecharva
Is there a way to disable referential integrity on all destination tables for an import?
Thanks.
Can someone give me an example on how to enforce cross-database referential integrity with triggers in SQL Server 2000?
Thanks,
Joel
In SQL Server 2012 (also 2005 and 2008), can you have Referential Integrity across a Database? Across a Schema?
View 1 Replies View RelatedI have transaction table where the rows entered into the transactioncan come a result of changes that take place if four different tables.So the situation is as follows:Transaction Table-TranId-Calc AmountTable 1 (the amount is inserted into the transaction table)- Tb1Id- Tb1AmtTable 2 (an amount is calculated based on the percentage and insertedinto the transaction table)-Tbl2Id-Tb2PercentageTable 3 (the amount is inserted into the transaction table)-Tbl3Id-Tbl3AmutTable 4 (an amount is calculated based on the percentage and insertedinto the transaction table. )-Tbl2Id-Tb2PercentageHow do I create referential integrity between the Transaction table andthe rest of the tables. When I make changes to the values in Table 1 -4, I need to be able to reflect this in the Transaction table.Thanks.
View 6 Replies View RelatedI am using SQL server 2000. I have a parent table 'MimeTypes' with primary key 'mimetype'. This is referenced as foreign key in table 'AssetTypes' as column 'BaseMimeType'.
The referential constraint is simple :
alter table AssetTypes
add constraint FK_ASSETTYPES_REF_BASEMIMETYPE foreign key (BaseMimeType)
references MimeTypes (MimeType) on update no action on delete no action;
I have FOR Update trigger on parent table ('MimeTypes') which is as follows:
CREATE TRIGGER trg_MimeTypes_update ON MimeTypes FOR UPDATE
AS
IF UPDATE(MimeType)
BEGIN
UPDATE AssetTypes
SET BaseMimeType = (select MimeType from inserted)
FROM AssetTypes as A
JOIN deleted as d on A.BaseMimeType = d.MimeType
END;
********
The problem is simple. I want to execute a update query on parent table ('MimeTypes') which modifies 'mimetype' value referenced by child. I dont want to include cascade option in constraint.
When such query is executed error comes as : UPDATE statement conflicted with COLUMN REFERENCE constraint 'FK_ASSETTYPES_REF_BASEMIMETYPE'. The conflict occurred in database 'default.db', table 'AssetTypes', column 'BaseMimeType'.
*****
Is there any way to do this?
Hi there,
I am looking for a way to define a trigger that is a replacement for a multi-column foreign key.
I know how to a convert a single-column foreign key constraint into a trigger (i.e., to resolve diamond-structured references).
CREATE TABLE parent_tab
(
col_a INTEGER NOT NULL,
CONSTRAINT pk PRIMARY KEY(col_a)
);
CREATE TABLE child_tab
(
col_x INTEGER NOT NULL,
CONSTRAINT fk FOREIGN KEY (col_x) REFERENCES parent_tab(col_a) ON DELETE CASCADE
);
The conversion would remove the foreign key definition and add this trigger:
CREATE TRIGGER tr_single
ON parent_tab INSTEAD OF DELETE
AS BEGIN
DELETE FROM child_tab WHERE (child_tab.col_x IN (SELECT col_a FROM deleted))
DELETE FROM parent_tab WHERE (parent_tab.col_a IN (SELECT col_a FROM deleted))
END;
Unfortunately, now I need to resolve a situation where there is involved a multi-column foreign key.
CREATE TABLE parent_tab
(
col_a INTEGER NOT NULL,
col_b INTEGER NOT NULL,
CONSTRAINT pk PRIMARY KEY(col_a, col_b)
);
CREATE TABLE child_tab
(
col_x INTEGER NOT NULL,
col_y INTEGER NOT NULL,
CONSTRAINT fk FOREIGN KEY (col_x, col_y) REFERENCES parent_tab(col_a, col_b) ON DELETE CASCADE
);
This does not work, because the temporary table "deleted" might contain more than one row. How do I make sure that the values belong to the same row?
-- incorrect trigger, might delete too many rows
CREATE TRIGGER tr_single
ON parent_tab INSTEAD OF DELETE
AS BEGIN
DELETE FROM child_tab WHERE (child_tab.col_x IN (SELECT col_a FROM deleted) AND child_tab.col_y IN (SELECT col_b FROM deleted))
DELETE FROM parent_tab WHERE (parent_tab.col_a IN (SELECT col_a FROM deleted) AND parent_tab.col_b IN (SELECT col_b FROM deleted))
END;
-- some magic needed :-)
CREATE TRIGGER tr_single
ON parent_tab INSTEAD OF DELETE
AS BEGIN
DELETE FROM child_tab WHERE (child_tab.col_x IN (SELECT col_a FROM deleted AS t1) AND child_tab.col_y IN (SELECT col_b FROM deleted AS t2) AND row_id(t1) = row_id(t2))
DELETE FROM parent_tab WHERE (parent_tab.col_a IN (SELECT col_a FROM deleted AS t1) AND parent_tab.col_b IN (SELECT col_b FROM deleted AS t2) AND row_id(t1) = row_id(t2))
END;
I know the trigger definition above is ***... but I hope that it helps to make clear what I need.
Btw., I use SQL Server 2005.
Thanks in advance,
slowjoe
I am new to MS SQL2005 but I have started working with it and found a difference between what MS Access and MS SQL will allow. I have a large DB with many tables but my problem relates to one specific issue. I have a table named tblAreaCodes which holds all area codes for the US. I have another table named tblSupplier where there are multiple colums such as name address etc. and three columns named phac, ph2ac, orderac, and faxac. All are the same type (Int) as is the Primary key in the tblAreaCode table. I have linked each of the columns in the tblSupplier table back to the primary in the tblAreaCode table. All is fine except I can not set the relationship to cascade update or delete. I am unsure what this means or how to proceed since this works and is allowed in MS Access. Any help and or direction would be greatly appreciated.
LKP
I'm trying out this database layout under MS SQL (de), with primary multicolomn key, but ....
Let's say table A, has primary KEY on the field PK_A
Let's say table B, has primary KEY on the field PK_B
Now table C, has fields ID_A and ID_B, defined as multicolomn primary key, referencing obviuosly to the PK_A and PK_B values.
NOW THE PROBLEM !! :(
Let present you table D , with his beautiful field ID_C. :)
How can I succed in referencing with the ID_C field the primary multicolomn key of table C ??
I' designing the whole thing with access97+mde, but dragging the PK key of table C (ID_A & ID_B) over the table D (ID_C) doesn't work !!
Any help ??
Thanks in advance !!
H2O
Hi, I tried to delete a record in tblA which has an ID in tblB, i got error msg saying referential problem, please tell me what should i do? thanks.
View 2 Replies View RelatedHello every body,I need some clarification of concept regarding self referentialtables.consider we have a "Person" table that stores data about employees ofan organisation.in case a person change his name or any details we dont want to updateour database by loosing old information and adding new one. what weneed is to hold previous details as well as the new ones.theoratically for me its easy i will just add another row and linkthat row with one of the existing row. to do so i created a relationbetween the "Emp_id" column of "Person" table to itself. so one"Emp_id" could be related to another "Emp_id" in the same table.after doing so i dont know how can i indicate while inserting a recordthat this new record in linked with one of the previous records. meansin insert statement how the relation ship would be added.here i am not sure if i am thinking in the right direction or not aswe may need to add another table or another column to indicate therelation between old an new row. but if we have to add that new columnsay "old_Emp_id" in "Person" table then what does the relationshipbetween "Emp_id" with itself serves.thanksAli
View 4 Replies View RelatedIs it possible to define a referential constraint between two tables in two different databases (on two servers)? Or are there beter best practices methods/products to achieve this result.
View 4 Replies View RelatedHi all,
Just wondering what would be the normal or more efficient practice to insert/update a record.
1. Check for existence of primary record (using SELECT in stored procedure)
2. Capture error and handling
My problem is that I try to execute an stored procedure from a VB client.. but unable to capture the errors in SP, it just prompts the error and thats it, not responding to my "SELECT @err = @@ERROR" after the insert statement.
so now, I'm thinking of capturing the error on the client (which I am able to do) and handle it from there.. or to make sure that RI is enforced by 'searching' for Pks in the primary tables before executing the INSERT statement in my stored procedure.
Any advise would be appreciated..
Cyherus