Referential Integrity With Empty String And ZERO
Jul 7, 2007Hi,
How could I define referential integrity using FK constraint which allow me to have empty string/ZERO number instead of NULL value ?
Thank you
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Referential Integrity Constraints W/o Referential Integrity In The Db?
Mar 16, 2007Using 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.
Referential Integrity ?
Aug 11, 2001Question:
What is used to enforce referential integrity ?
Answer: Triggers; Foriegn Keys.
what is Foreign Keys ?
Referential Integrity
Oct 17, 2001How do you enforce referential integrity in SQL between tables?
Thanks.
I Have Referential Integrity. Now What
Feb 26, 2008I 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?
Referential Integrity
Oct 26, 2004Hi 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
Referential Integrity
Feb 1, 2008hi 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????
Referential Integrity
Dec 23, 2005Hihow 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 RelatedReferential Integrity Done By Trigger
Nov 10, 1998I'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 Replies View RelatedReferential Integrity Without Foreign Key
Apr 21, 2008What ate the method/techniques i can use for enforcing referential integrity, Without using foreign key constraints ?
View 7 Replies View RelatedReferential Integrity Problem
Jun 3, 2006I'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 RelatedReferential Integrity (FK) Between Differents Databases
Aug 11, 2000How I do, in SQL SERVER 7.0, referential integrity (Foreign Key constraints) between tables storaged in differents databases?.
Thank for any help.
Referential Integrity Trigger---Urgent Pls
Oct 4, 2000Hi,
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
Referential Integrity Trigger---Urgent Pls
Oct 4, 2000Hi,
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
Referential Integrity - Which Column Violates This?
Oct 4, 2004Hi 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
Referential Integrity In Mutiple Tables. Need Help.
Oct 12, 2004I 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?
DELETING ROWS With REFERENTIAL INTEGRITY
Dec 7, 2006hi 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...
Creating Referential Integrity Constraints
Aug 24, 2006Two 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
Problems With Procedural Referential Integrity
Nov 19, 2007Hello 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
Problem Retaining Referential Integrity In My Data
Apr 12, 2007I'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
Disabling Referential Integrity Database-wide On Import
Apr 10, 2006Is there a way to disable referential integrity on all destination tables for an import?
Thanks.
How To Use Triggers To Enforce Cross-database Referential Integrity?
Aug 1, 2001Can someone give me an example on how to enforce cross-database referential integrity with triggers in SQL Server 2000?
Thanks,
Joel
SQL 2012 :: Server Referential Integrity Across Database - Schema?
Sep 19, 2014In SQL Server 2012 (also 2005 and 2008), can you have Referential Integrity across a Database? Across a Schema?
View 1 Replies View RelatedReferential Integrity - Linking Multiple Tables To Transaction Table
Mar 3, 2006I 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 RelatedSQL - Cascading Delete, Or Delete Trigger, Maintaining Referential Integrity - PLEASE HELP ME!!!
Nov 13, 2006I 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
Empty String To Null
Jul 11, 2001example
create view v_GuestOrder
as
Select T1.id_Guest,T2.OrderName
from Guest T1
left join Order T2 T2.id_order = T1.Id_order
select * from v_GuestOrder
--
Id_Guest OrderName
-------- -----
1 spoon
2 phone
3
4 tv
I need something similar to
Select
id_Guest,
case orderName
when '' then Null -- Sql server gives error in thsi case
end as orderName
from v_GuestOrder
So I need to assign NULL to OrderName is query return empty string,
it will be treated by Crystal reports as Null
Please help , thanks
Bcp Out Empty String Into Csv Files
Jun 19, 2008I have a SQL Server table with nvarchar type column which has not null constraint. I am inserting empty string ("") from Java to the table column. When I export this table into .csv file using bcp tool, empty string gets written as NUL character. Is there any way I can bcp out empty string as empty string itself instead of NUL to the file?
View 3 Replies View RelatedConstraint For An Empty String
Jul 27, 2007How do I prevent a column having empty strings entered into it. I want to allow
nulls but not allow empty strings.
Paul
Order By String Not Empty?
Jul 20, 2005Hi ng.I have a varchar field in my table, called Name.I wanna do a selection, which is ordered by whether this field is empty ornot.E.g. something like:SELECTUserIDORDER BYName <> '';- - -How can I accomplish this?TIA.Klaus.
View 4 Replies View RelatedHow To Cast Empty String
Mar 22, 2006I want to replace a column value with a null if the string is empty. I would have thought this simple expression would do it:
RTRIM([FromContractSymbol]) == "" ? NULL(DT_STR, 0, 1252) : (DT_STR, 6, 1252)FromContractSymbol
Yet, I get the following error:
For operands of the conditional operator, the data type DT_STR is supported only for input columns and cast operators. The expression "...see above..." has a DT_STR operand that is not an input column or the result of a cast, and cannot be used with the conditional operation.
The expression works if I replace the NULL(DT_STR, 0, 1252) with say "A" and the expression works on other non-string columns. (As in "NULL(DT_I1) : (DT_I1)100")
Checking If String Is NULL Or EMPTY In SQL
Nov 9, 2007I need to check in my Stored procedure if the information passed is null or empty so I can decided to insert the new value or keep the old. How do I accomplish this please in T-SQL. Thanks in advance.
View 6 Replies View RelatedInsert Empty String Or Null To Sql Db
Jan 12, 2008Hi:
Trying to insert null value into sql table, but not working, if I use:
if (strMyText.Length == 0) command.Parameters.Add("@Text", DBNull.Value); // or using:("@Text", null), or using:("@Text", DBNull) else command.Parameters.AddWithValue("@Text", strMyText);
When I go back to table, I see the value is: 'NULL', has single quotation mark, suppose to be: NULL
Where is the problem?
Thanks a lot.
Jt
Null Or Empty String Use More Space?
Aug 9, 2005Hi all, I have some columns in my database which allows null. I want to know if leaving the field to be NULL or storing an empty string into the field, which will take up more space?? if the field type is varchar(100)
View 5 Replies View Related