I have 3 tables tblteam, tblaccount and tbluser with the following columns:
tblTeam:
(TeamId int,
TeamName varchar(20),
IsDeleted bit)
tblUser:
(UserId int,
UserName varchar(20),
TeamId int)
tblAccount:
(AccountId int,
AccountName varchar(20),
TeamId int,
UserId int
)
What I want to do is I want to update the deleted column with 1.
For this I have tried
Create procedure sp_isdeleted(
#pteamid int
As
Begin
Update tblTeam
set IsDeleted = 1
Where TeamId = #pteamid
End
But what I want is, if team is associated with any user or account and any user remains in the team Isdeleted remains 0.
How can I check this condition? Please help.
Try this update statement inside the SP:
Update t
set t.IsDeleted = 1
from tblTeam t
where t.TeamId = #pteamid
and not exists (select 1 from tblUser where TeamId = #pteamid)
and not exists (select 1 from tblAcount where TeamId = #pteamid)
If you put the logic into one place or many places, there is still the possibility that the soft delete could be performed from some other place. You want to make it impossible to make the deletion from anywhere at any time. Wouldn't it be nice if the system would enforce the default FK restriction (cannot delete a row if there is any FK referring to it) for a soft delete just as it does a hard delete? Say, there's an idea! And it's really quite simple to implement.
Just make the deletion flag part of the PK of the table (or better yet, just add it with the PK to a unique index). Then every FK to Team uses a 0 value in that field. Any attempt to modify the IsDeleted field will be prevented if there is any FK anywhere referring to that Team.
This is from memory so the syntax could be iffy:
create table Teams(
ID int not null,
IsDeleted bit not null default 0,
...
constraint PK_Teams primary key( ID )
);
create unique index UQ_Team_ID_IsDeleted on Team( ID, IsDeleted );
create table AllOthers(
...
TeamID int,
TeamStillThere bit,
...
constraint CK_TeamStillThere check IsNull( TeamStillThere, 0 ) = 0;
constraint FK_AllOthers_Teams foreign key( TeamID, TeamStillThere )
references Teams( ID, IsDeleted );
);
Notice that the FK can only refer to an undeleted team and, once a connection is made, the team cannot be deleted( hard or soft). Plus, you can still define FK references to just the PK if that reference doesn't care if the team is deleted or not -- a history of the team, for example. Either way, let the system do all the work wherever possible.
Related
I'm trying to wrap my head around how to accomplish this Delete query. The goal is I'm trying to delete a client record (main table) based on if they don't have an insurance policy (another table) and if their needs description is "transportation" and importance values is LESS than 5. The needs is another table. They are all connected with foreign keys and SSN as the connector and Delete cascade is working properly. The query is partially working as is. If there is no insurance policy, the Client is being deleted correctly. However, the need description and importance value factors are not currently working. It will still delete if I have no insurance policy, but my importance description is another value other than transportation.
It's almost like I need 2 subqueries compare both Needs table and Insurance_Policy table for deletion, but I don't know how to do that.
The database I'm using is Azure Data Studio
Here is my current Procedure code:
DROP PROCEDURE IF EXISTS Option17;
GO
CREATE PROCEDURE Option17
AS
BEGIN
DELETE FROM Client
WHERE Client.SSN NOT IN (SELECT I.SSN
FROM Insurance_Policy I, Needs N
WHERE Client.SSN = I.SSN
AND Client.SSN = N.SSN
AND N.need_description = 'transportation'
AND N.importance_value < 5)
END
Also, here are my table structures:
CREATE TABLE Client
(
SSN VARCHAR(9),
doctor_name VARCHAR(60),
doctor_phone_no VARCHAR(10),
lawyer_name VARCHAR(60),
lawyer_phone_no VARCHAR(10),
date_assigned DATE,
PRIMARY KEY (SSN),
FOREIGN KEY (SSN) REFERENCES Person
ON DELETE CASCADE
);
CREATE TABLE Insurance_Policy
(
policy_id VARCHAR(10),
provider_id VARCHAR(10),
provider_address VARCHAR(100),
insurance_type VARCHAR(10),
SSN VARCHAR(9),
PRIMARY KEY (policy_id),
FOREIGN KEY (SSN) REFERENCES Client,
);
CREATE TABLE Needs
(
SSN VARCHAR(9),
need_description VARCHAR(60),
importance_value INT CHECK(importance_value > 0 and importance_value <11),
PRIMARY KEY(SSN,need_description),
FOREIGN KEY(SSN) REFERENCES Client
ON DELETE CASCADE
);
Here is a screenshot if the formatting didn't hold up on procedure.
enter image description here
Based on your answers, I believe this is the code you are looking for. If this is not working, let me know.
To explain a little, using an INNER join will eliminate the need for a couple of those WHERE conditions. INNER JOIN only returns records where it exists in both tables. Also there is no need to link to the Client table from within the subquery.
Also you want where it does not have a description of transportation with an importance of less than 5. Since you are pulling a list to leave alone, you do not want to include these records.
DROP PROC IF EXISTS Option17;
GO
Create proc Option17
AS
BEGIN
DELETE FROM Client
WHERE SSN NOT IN (
SELECT
N.SSN
FROM Needs N
INNER JOIN Insurance_Policy I ON N.SSN = I.SSN
WHERE NOT (N.need_description = 'transportation' AND N.importance_value < 5)
);
END
GO
I think you want separate conditions on Needs and Insurance_Policy. And I recommend NOT EXISTS, because it better handles NULL values:
DELETE c
FROM Client c
WHERE NOT EXISTS (SELECT 1
FROM Insurance i
WHERE c.SSN = i.SSN
) AND
EXISTS (SELECT 1
FROM Needs n
WHERE c.SSN = n.SSN AND
n.need_description = 'transportation' AND
n.importance_value < 5
);
I'm designing a new database for a company, trying to keep strict constraints with foreign keys etc for integrity. I have a table [Member] which holds companies on the system. This table has a column of [internalContact] for the user in our company who deals with this member which has a foreign linked to the users table by user id.
What I would like to know is if it is possible to assign a condition to the foreign key, since the users table contains internal and external users. ie. for the field to only accept a user id where the user type is 5. Can this be done, or can I only control this in my application code?
Thanks
You can use a check constraint for this.
(The code is untested some syntax errors will be in there)
CREATE TABLE Member
(
P_Id int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Address varchar(255),
City varchar(255),
InternalContactId
CONSTRAINT chk_Person CHECK (isInternalUser(internalContactId) > 0)
)
ALTER TABLE Member
ADD FOREIGN KEY (InternalContacId)
REFERENCES Persons(P_Id)
Then just create a function isInternalUser that returns 1 if user in ok to be an internal contact
CREATE FUNCTION isInternalUser ( #userId int(10) )
RETURNS int
AS
BEGIN
DECLARE #tmp int
SELECT #tmp = count(*)
FROM users
WHERE userId = #UserId and <check to see if user is internal>
RETURN(#CtrPrice)
END
GO
Im a beginner in database and i got this difficult auction database project.
Im using SQL Server Management Studio also.
create table user(
name char(10) not null,
lastname char(10) not null
)
create table item(
buyer varchar(10) null,
seller varchar(10) not null,
startprice numeric(5) not null,
description char(22) not null,
start_date datetime not null,
end_date datetime not null,
seller char(10) not null,
item_nummer numeric(9) not null,
constraint fk_user foreign key (buyer) references user (name)
)
Basically what the rule im trying to make here is:
Column buyer has NULL unless the time (start_date and end_date) is over and startprice didnt go up or increased. Then column buyer will get the name from table user who bidded on the item.
The rule is a bid too difficult for me to make, i was thinking to make a trigger, but im not sure..
Your model is incorrect. First you need a table to store the bids. Then when the auction is over, you update the highest one as the winning bid. Proably the best way is to have a job that runs once a minute and finds the winners of any newly closed auctions.
A trigger will not work on the two tables you have because triggers only fire on insert/update or delete. It would not fire because the time is past. Further triggers are an advanced technique and a db beginner should avoid them as you can do horrendous damage with a badly written trigger.
You could have a trigger that works on insert to the bids table, that updates the bid to be the winner and takes that status away from the previous winner. Then you simply stop accepting new bids at the time the auction is over. Your application could show the bidder who is marked as the winner as the elader if the auction is till open and teh winner if it is closed.
There are some initial problems with your schema that need addressed before tackling your question. Here are changes I would make to significantly ease the implementation of the answer:
-- Added brackets around User b/c "user" is a reserved keyword
-- Added INT Identity PK to [User]
CREATE TABLE [user]
(
UserId INT NOT NULL
IDENTITY
PRIMARY KEY
, name CHAR(10) NOT NULL
, lastname CHAR(10) NOT NULL
)
/* changed item_nummer (I'm not sure what a nummer is...) to ItemId int not null identity primary key
Removed duplicate Seller columns and buyer column
Replaced buyer/seller columns with FK references to [User].UserId
Add currentBid to capture current bid
Added CurrentHighBidderId
Added WinningBidderId as computed column
*/
CREATE TABLE item
(
ItemId INT NOT NULL
IDENTITY
PRIMARY KEY
, SellerId INT NOT NULL
FOREIGN KEY REFERENCES [User] ( UserId )
, CurrentHighBidderId INT NULL
FOREIGN KEY REFERENCES [User] ( UserId )
, CurrentBid MONEY NOT NULL
, StartPrice NUMERIC(5) NOT NULL
, Description CHAR(22) NOT NULL
, StartDate DATETIME NOT NULL
, EndDate DATETIME NOT NULL
)
go
ALTER TABLE dbo.item ADD
WinningBidderId AS CASE WHEN EndDate < CURRENT_TIMESTAMP
AND currentBid > StartPrice THEN CurrentHighBidderId ELSE NULL END
GO
With the additional columns a computed column can return the correct information. If you must return the winner's name instead of id, then you could keep the schema above the same, add an additional column to store the user's name, populate it with a trigger and keep the computed column to conditionally show/not show the winner..
I'm using SQL Server 2005 and wish to create a number address records, updating the contact records with the new Id's:
Take the following tables
create table contact(id int primary key identity, home_address_id int, work_address_id int)
create table address(id int primary key identity, street varchar(25), number int)
And foreign keys:
ALTER TABLE dbo.contact ADD CONSTRAINT FK_contact_address1 FOREIGN KEY (home_address_id) REFERENCES dbo.address(id)
ALTER TABLE dbo.contact ADD CONSTRAINT FK_contact_address2 FOREIGN KEY (work_address_id) REFERENCES dbo.address(id)
some dummy data
insert into contact default values
insert into contact default values
insert into contact default values
How can I insert a default empty address record for all contacts who have no home address, and update the home_address_id in one go?
The first part is simple:
insert into address(street) select null from contact where home_address_id is null
I can even get the newly create address id's:
declare #addressTable table(id int)
insert into address(street)
OUTPUT INSERTED.Id INTO #addressTable
select null from contact where home_address_id is null
Here's the new id's
select * from #addressTable
But how to update the contact table with these new Id's?
If possible, I would suggest normalizing your database by adding a Contact_Addresses table:
CREATE TABLE Contact_Addresses
(
contact_id INT NOT NULL,
address_id INT NOT NULL,
address_type VARCHAR(10) NOT NULL,
CONSTRAINT PK_Contact_Addresses PRIMARY KEY CLUSTERED (contact_id, address_id, address_type),
CONSTRAINT FK_ContactAddresses_Contacts (contact_id) REFERENCES Contacts (id),
CONSTRAINT FK_ContactAddresses_Addresses (address_id) REFERENCES Addresses (id),
CONSTRAINT CK_ContactAddresses_address_type CHECK address_type IN ('HOME', 'WORK')
)
Next, I would suggest not putting "dummy" records in your database. It's going to end up causing headaches down the road. The database should contain an accurate record of the data in your system. If you want to display some value by default when no address exists in the system for a contact then handle that in your UI.
If you really must though, then the following code should do the trick:
;WITH C_CTE AS
(
SELECT
id,
home_address_id,
ROW_NUMBER() OVER(ORDER BY id) AS seq
FROM
Contacts
),
(
SELECT
id,
ROW_NUMBER() OVER(ORDER BY id) AS seq
FROM
Addresses
)
UPDATE
C_CTE
SET
home_address_id = A.id
FROM
C_CTE C
INNER JOIN A_CTE A ON A.seq = C.seq
I would do it from the moment you get a new contact, thusly:
[receive contact information]
//prior to inserting contact
declare #homeAddress int, #workAddress int
[insert home address here (real or default based on input)]
set #homeAddress = ##Identity
[insert work address here (real or default)]
set #workAddress = ##Identity
[insert contact here referencing #homeAddress & #workAddress]
For the stuff already in your table, you're going to have to associate all of your null value ids to a contact id. Or, you could clear out your null value addresses, and modify the above statement to an update somehow (brain's not working at the moment, so all I'm coming up with is a cursor, and cursors are evil).
How could I set a constraint on a table so that only one of the records has its isDefault bit field set to 1?
The constraint is not table scope, but one default per set of rows, specified by a FormID.
Use a unique filtered index
On SQL Server 2008 or higher you can simply use a unique filtered index
CREATE UNIQUE INDEX IX_TableName_FormID_isDefault
ON TableName(FormID)
WHERE isDefault = 1
Where the table is
CREATE TABLE TableName(
FormID INT NOT NULL,
isDefault BIT NOT NULL
)
For example if you try to insert many rows with the same FormID and isDefault set to 1 you will have this error:
Cannot insert duplicate key row in object 'dbo.TableName' with unique
index 'IX_TableName_FormID_isDefault'. The duplicate key value is (1).
Source: http://technet.microsoft.com/en-us/library/cc280372.aspx
Here's a modification of Damien_The_Unbeliever's solution that allows one default per FormID.
CREATE VIEW form_defaults
AS
SELECT FormID
FROM whatever
WHERE isDefault = 1
GO
CREATE UNIQUE CLUSTERED INDEX ix_form_defaults on form_defaults (FormID)
GO
But the serious relational folks will tell you this information should just be in another table.
CREATE TABLE form
FormID int NOT NULL PRIMARY KEY
DefaultWhateverID int FOREIGN KEY REFERENCES Whatever(ID)
From a normalization perspective, this would be an inefficient way of storing a single fact.
I would opt to hold this information at a higher level, by storing (in a different table) a foreign key to the identifier of the row which is considered to be the default.
CREATE TABLE [dbo].[Foo](
[Id] [int] NOT NULL,
CONSTRAINT [PK_Foo] PRIMARY KEY CLUSTERED
(
[Id] ASC
) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[DefaultSettings](
[DefaultFoo] [int] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[DefaultSettings] WITH CHECK ADD CONSTRAINT [FK_DefaultSettings_Foo] FOREIGN KEY([DefaultFoo])
REFERENCES [dbo].[Foo] ([Id])
GO
ALTER TABLE [dbo].[DefaultSettings] CHECK CONSTRAINT [FK_DefaultSettings_Foo]
GO
You could use an insert/update trigger.
Within the trigger after an insert or update, if the count of rows with isDefault = 1 is more than 1, then rollback the transaction.
CREATE VIEW vOnlyOneDefault
AS
SELECT 1 as Lock
FROM <underlying table>
WHERE Default = 1
GO
CREATE UNIQUE CLUSTERED INDEX IX_vOnlyOneDefault on vOnlyOneDefault (Lock)
GO
You'll need to have the right ANSI settings turned on for this.
I don't know about SQLServer.But if it supports Function-Based Indexes like in Oracle, I hope this can be translated, if not, sorry.
You can do an index like this on suposed that default value is 1234, the column is DEFAULT_COLUMN and ID_COLUMN is the primary key:
CREATE
UNIQUE
INDEX only_one_default
ON my_table
( DECODE(DEFAULT_COLUMN, 1234, -1, ID_COLUMN) )
This DDL creates an unique index indexing -1 if the value of DEFAULT_COLUMN is 1234 and ID_COLUMN in any other case. Then, if two columns have DEFAULT_COLUMN value, it raises an exception.
The question implies to me that you have a primary table that has some child records and one of those child records will be the default record. Using address and a separate default table here is an example of how to make that happen using third normal form. Of course I don't know if it's valuable to answer something that is so old but it struck my fancy.
--drop table dev.defaultAddress;
--drop table dev.addresses;
--drop table dev.people;
CREATE TABLE [dev].[people](
[Id] [int] identity primary key,
name char(20)
)
GO
CREATE TABLE [dev].[Addresses](
id int identity primary key,
peopleId int foreign key references dev.people(id),
address varchar(100)
) ON [PRIMARY]
GO
CREATE TABLE [dev].[defaultAddress](
id int identity primary key,
peopleId int foreign key references dev.people(id),
addressesId int foreign key references dev.addresses(id))
go
create unique index defaultAddress on dev.defaultAddress (peopleId)
go
create unique index idx_addr_id_person on dev.addresses(peopleid,id);
go
ALTER TABLE dev.defaultAddress
ADD CONSTRAINT FK_Def_People_Address
FOREIGN KEY(peopleID, addressesID)
REFERENCES dev.Addresses(peopleId, id)
go
insert into dev.people (name)
select 'Bill' union
select 'John' union
select 'Harry'
insert into dev.Addresses (peopleid, address)
select 1, '123 someplace' union
select 1,'work place' union
select 2,'home address' union
select 3,'some address'
insert into dev.defaultaddress (peopleId, addressesid)
select 1,1 union
select 2,3
-- so two home addresses are default now
-- try adding another default address to Bill and you get an error
select * from dev.people
join dev.addresses on people.id = addresses.peopleid
left join dev.defaultAddress on defaultAddress.peopleid = people.id and defaultaddress.addressesid = addresses.id
insert into dev.defaultaddress (peopleId, addressesId)
select 1,2
GO
You could do it through an instead of trigger, or if you want it as a constraint create a constraint that references a function that checks for a row that has the default set to 1
EDIT oops, needs to be <=
Create table mytable(id1 int, defaultX bit not null default(0))
go
create Function dbo.fx_DefaultExists()
returns int as
Begin
Declare #Ret int
Set #ret = 0
Select #ret = count(1) from mytable
Where defaultX = 1
Return #ret
End
GO
Alter table mytable add
CONSTRAINT [CHK_DEFAULT_SET] CHECK
(([dbo].fx_DefaultExists()<=(1)))
GO
Insert into mytable (id1, defaultX) values (1,1)
Insert into mytable (id1, defaultX) values (2,1)
This is a fairly complex process that cannot be handled through a simple constraint.
We do this through a trigger. However before you write the trigger you need to be able to answer several things:
do we want to fail the insert if a default exists, change it to 0 instead of 1 or change the existing default to 0 and leave this one as 1?
what do we want to do if the default record is deleted and other non default records are still there? Do we make one the default, if so how do we determine which one?
You will also need to be very, very careful to make the trigger handle multiple row processing. For instance a client might decide that all of the records of a particular type should be the default. You wouldn't change a million records one at a time, so this trigger needs to be able to handle that. It also needs to handle that without looping or the use of a cursor (you really don't want the type of transaction discussed above to take hours locking up the table the whole time).
You also need a very extensive tesing scenario for this trigger before it goes live. You need to test:
adding a record with no default and it is the first record for that customer
adding a record with a default and it is the first record for that customer
adding a record with no default and it is the not the first record for that customer
adding a record with a default and it is the not the first record for that customer
Updating a record to have the default when no other record has it (assuming you don't require one record to always be set as the deafault)
Updating a record to remove the default
Deleting the record with the deafult
Deleting a record without the default
Performing a mass insert with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record inserts
Performing a mass update with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record updates
Performing a mass delete with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record deletes
#Andy Jones gave an answer above closest to mine, but bearing in mind the Rule of Three, I placed the logic directly in the stored proc that updates this table. This was my simple solution. If I need to update the table from elsewhere, I will move the logic to a trigger. The one default rule applies to each set of records specified by a FormID and a ConfigID:
ALTER proc [dbo].[cpForm_UpdateLinkedReport]
#reportLinkId int,
#defaultYN bit,
#linkName nvarchar(150)
as
if #defaultYN = 1
begin
declare #formId int, #configId int
select #formId = FormID, #configId = ConfigID from csReportLink where ReportLinkID = #reportLinkId
update csReportLink set DefaultYN = 0 where isnull(ConfigID, #configId) = #configId and FormID = #formId
end
update
csReportLink
set
DefaultYN = #defaultYN,
LinkName = #linkName
where
ReportLinkID = #reportLinkId