how can this statement:
DELETE FROM passage
WHERE passageid NOT IN
(
SELECT passageid from PreEndedPassages_passages
UNION SELECT fromPassageid from severalvisit
UNION SELECT toPassageid from severalvisit
UNION SELECT registerPassageid from stationobjects WHERE registerpassageid IS NOT NULL
UNION SELECT beginPassageid from stationobjects WHERE beginPassageid IS NOT NULL
UNION SELECT endPassageid from stationobjects WHERE endPassageid IS NOT NULL
)
throw this exception?
The DELETE statement conflicted with the FOREIGN KEY constraint "FK_statobj_begpasid". The conflict occurred in database "db.mdf", table "dbo.stationobjects", column 'beginpassageid'.
I have no clue, but it happened. beginPassageId is a foreign key on passageid.
EDIT:
Consider the NOT IN. I want to delete all passages that don't exist in one of its related tables. It usually works, but it happened once.
Thank you.
It means passage is parent table. and stationobjects is child table. You are trying to remove passageid from passage table which is present in stationobjects table as well.
First try to remove those passageid from stationobjects and then you can run this delete statement.
Alternate approach is cascade delete, if your DB supports that.
this kind of occur when you have a foreign key relationship in the two table.
This violates the Refrential Integrity .
so if you delete record from the primary table and record exist in foreign key table,
then you have two options:
1. either set the delete rule to cascade so that when ever you delete primary record the foreign key table record will get automatically deleted.
2.delete record from foreign key table first then from primary key table.
These kind of errors come up when table A foreign key is table B primary key and when you try to delete record in table A that has linking in table B, then deletion will not happen. Try dropping foreign key relation before delete. Same way truncate is used in tables by dropping fk relations and rebuilding them again after the table is reset
Related
I am trying to insert a row into my database table, but I keep on getting a SQL error.
I have a table called tbl_template_log, it has 3 Forgain Keys, user_id, temp_id, savedtemp_id, at the moment I only want to Insert a row with user_id and set temp_id and savedtemp_id to 0.
Query:
INSERT INTO tbl_template_log (user_id, temp_id, savetemp_id, send_date, send_to, email_send) VALUES (user_id=77, temp_id=0, savetemp_id=0, send_date='2013-10-10', send_to='test#test.com', email_send='hello')
Error:
INSERT INTO tbl_template_log (user_id, temp_id, savetemp_id, send_date, send_to, email_send) VALUES (user_id=77, temp_id=0, savetemp_id=0, send_date='2013-10-10', send_to='test#test.com', email_send='hello')
MySQL said: Documentation
#1452 - Cannot add or update a child row: a foreign key constraint fails (`admin_boltmail`.`tbl_template_log`, CONSTRAINT `tbl_template_log_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `tbl_user` (`user_id`))
From What I understand there is some sort of issue with user_id that the ID of the user has to be existing in tbl_user and ID 77 is an existing user id.....
Could some one point out a mistake I am doing. Thx
You can't add a row to this table unless the other tables specified in your foreign key constraints already have a record with the field value you're trying to insert. That's what a foreign key constraint means.
You're trying to break the rule you defined on your table. No, the database won't let you break the rule. You'll either have to add records to the foreign key tables or disable the constraints.
I have a stored procedure that deletes a record from a table where one of the columns matches a specified value:
ALTER PROCEDURE [dbo].[Sp_DelBranch] #datafield varchar(50)
AS
BEGIN
DELETE FROM Branch WHERE branchname = #datafield
END
Unfortunately I get the following error on execution:
The DELETE statement conflicted with the REFERENCE constraint "fk_BranchIdDept". The conflict occurred in database "MproWorkSpace", table "dbo.Department", column 'BranchId'.
Can anyone explain why I'm seeing this error?
conflicted with the REFERENCE constraint "fk_BranchIdDept".
This means, that the value you are trying to delete, is primary key in some other table and is referenced in this table as foreign key,i.e., a primary-foreign key relation is mapped through constraint fk_BranchIdDept ...So unless you delete the referred primary key, foreign key can not be removed from table.
Otherwise, this will lead to data inconsistency!
Look for Cascade Delete to help you in this!
SQL ON DELETE CASCADE, Which Way Does the Deletion Occur?
The DELETE statement conflicted with the REFERENCE constraint "fk_BranchIdDept".
The record you're trying to delete is referenced in other tables; deleting the Branch record would leave the other tables orphaned, and referencing something that no longer exists.
There are two approaches to this:
Delete all records in referenced tables before deleting from the Branch table
Perform a cascade delete (deleting from the Branch table triggers a delete in every referenced table)
The error means that there are some rows in Department table referencing the branch you're trying to delete.
You should either delete the corresponding rows from the Department table first, or change values in BranchId column for these rows, so they point to some other branch.
I know that this question belongs to the very early stages of the database theory, but I have not encountered such a problem since several months. If someone has a database with some tables associated together as "chain" with foreign keys and they want to delete a record from a table which has some "dependent" tables, what obstacles arise? In particular, in a database with tables: Person, Profile, Preference, Filter exist the associations as Person.id is foreign key in Profile and Profile.id is foreign key in Preference and Filter.id is foreign key in Preference, so as that all the associationsenter code here are OneToMany. Is it possible to delete a Person with a simple query:
Delete from Person p where p.id= 34;
If no, how should look like the query in order to perform the delete successfully?
If the database in the application is managed by hibernate, what constraints (annotations) should I apply to the associated fields of each entity, so as to be able with the above simple query to perform the delete?
FOR SQL VERSION
Look at the Screenshot. you can use the Insert Update Specificaiton Rules. as it has Delete and Update Rules. you can set either of these values.
Foreign key constraints may be created by referencing a primary or unique key. Foreign key constraints ensure the relational integrity of data in associated tables. A foreign key value may be NULL and indicates a particular record has no parent record. But if a value exists, then it is bound to have an associated value in a parent table. When applying update or delete operations on parent tables there may be different requirements about the effect on associated values in child tables. There are four available options in SQL Server 2005 and 2008 as follows:
No Action
Cascade
SET NULL
SET Default
Use this article for Refrence.
http://www.mssqltips.com/sqlservertip/2365/sql-server-foreign-key-update-and-delete-rules/
ORACLE VERSION
you can use one of below.
alter table sample1
add foreign key (col1)
references
sample (col2)
on delete no action;
alter table sample1
add foreign key (col1)
references
sample (col2)
on delete restrict;
alter table sample1
add foreign key (col1)
references sample (col2)
on delete cascade;
for refrance.
http://docs.oracle.com/cd/B19306_01/server.102/b14200/clauses002.htm
answer is no if there is foreign key constraint then you have to delete leaf node table data first
that is first delete from Preference table
then from Profile and Filter Table
then delete record from Person table
This is the generic concept that you apply anywhere
so i have 2 tables related to each other with an fk
appointment
{id, dept.id, datetime, sometable.id, sometableagain.id}
task
{id, appointment.id, deptlead.id, taskname}
deptlead
{id, name}
so i had to alter the appointment table to another foreignkey from another table. so i dropped the keys (task_appointment_fk, appointment_sometable_fk, appointment_sometableagain_fk) altered the table to add the new field and added again everything. the last two got added with no problems. while the other one (task_appointment_fk) kept giving me a this message :
"ALTER TABLE statement conflicted with the Forien Key Constraint "dept_appointment". The Cconflict occurred in the database "MyDb" , table "appointment", column "id"
so i found some solutions that states that there might be some rows on the task that has a appointmentid value that does not exist on the appointment table. so i tried inserting rows that would have the same value right. still gives me the same thing. the thing is , i want to delete the rows from the task to make it easier but doing that i have to drop all the fks again and do the same thing all over on the other tables, and i have a lot of other tables..
need some advice.
thanks!!
You can write a query to see which values in foreign key table does not have a matching key record in primary key table .If values are there then try to delete them .
select * from [task] a
left join [appointment] b
on a.appointment_id = b.id
I know the question of how to update multiple tables in SQL has been asked before and the common answer seems to be do them separately in a transaction.
However, the 2 columns I need to update have a foreign key so cannot be updated separately.
e.g.
Table1.a is a foreign key to Table2.a
One of the entries in the tables is wrong, e.g. both columns are 'xxx' and should be 'yyy'
How do I update Table1.a and Table2.a to be 'yyy'?
I know I could temp remove the key and replace but surely there's another way.
Thanks
You can't do the update simultaneously, however you can force SQL to do the update. You need to make sure your foreign keys have the referential triggered action ON UPDATE CASCADE
e.g.
ALTER TABLE YourTable
ADD CONSTRAINT FK_YourForeignKey
FOREIGN KEY (YourForeignKeyColumn)
REFERENCES YourPrimaryTable (YourPrimaryKeyColumn) ON UPDATE CASCADE
Not being a fan of on update cascade, I would suggest a different route.
First you do not update the Parent table, you add a new record with the value you want (and the same data as the other record for all other fields). Then you have no difficulty updating the child tables to use this value instead of that value. Further you now have the ability to to do the work in batches to avoid locking the system up while the change promulgates through it. Once all the child tables have been updated, you can delete the original bad record.
my answer is based on the following link: http://msdn.microsoft.com/en-us/library/ms174123%28v=SQL.90%29.aspx
You need to make sure that your table_constraint will be defined as ON UPDATE CASCADE
CREATE TABLE works_on1
(emp_no INTEGER NOT NULL,
project_no CHAR(4) NOT NULL,
job CHAR (15) NULL,
enter_date DATETIME NULL,
CONSTRAINT prim_works1 PRIMARY KEY(emp_no, project_no),
CONSTRAINT foreign1_works1 FOREIGN KEY(emp_no) REFERENCES employee(emp_no) ON DELETE CASCADE,
CONSTRAINT foreign2_works1 FOREIGN KEY(project_no) REFERENCES project(project_no) ON UPDATE CASCADE)
and then when you will change the value of your primary key
see the following quote:
For ON DELETE or ON UPDATE, if the CASCADE option is specified, the
row is updated in the referencing table if the corresponding
referenced row is updated in the parent table. If NO ACTION is
specified, SQL Server Compact Edition returns an error, and the update
action on the referenced row in the parent table is rolled back.
For example, you might have two tables, A and B, in a database. Table
A has a referential relationship with table B: the A.ItemID foreign
key references the B.ItemID primary key.
If an UPDATE statement is executed on a row in table B and an ON
UPDATE CASCADE action is specified for A.ItemID, SQL Server Compact
Edition checks for one or more dependent rows in table A. If any
exist, the dependent rows in table A are updated, as is the row
referenced in table B.
Alternatively, if NO ACTION is specified, SQL Server Compact Edition
returns an error and rolls back the update action on the referenced
row in table B when there is at least one row in table A that
references it.