I have the following tables :
create table ApartmentInfo(
ApartmentId int primary key identity,
ApName nvarchar(50))
create table [User](
UserId int primary key identity,
FirstName nvarchar(50),
LastName nvarchar(50),
Username nvarchar(50),
[Password] nvarchar(50),
[Description] nvarchar(200))
create table ApUser(
ApartmentId int foreign key references ApartmentInfo(ApartmentId),
UserId int foreign key references [User](UserId),
primary key(ApartmentId,UserId))
Summary of the usage is: suppose I have 10 apartments in my Apartmentinfo table and 3 users in the [User] table.
Now I want to write a stored procedure such that:
every UserId has all 10 ApartmentId's, and whenever a new apartment is created in ApartmentInfo table it will also be added in ApUser table again having all 3 userId's.
And if a new user is created in User table then it will also have all the 10 ApartmentId's related with it in ApUser table.
Thanks in advance, I am new to SQL Server and I don't know how it can be done or not but, if it is possible then please let me know, I will be grateful to you, thanks.
If you're not dead set on using a stored procedure this use case seems like an excellent fit for server side triggers:
IF EXISTS (SELECT * FROM sys.triggers WHERE object_id = OBJECT_ID(N'[dbo].[trigger_insert_apartment]'))
DROP TRIGGER [dbo].[trigger_insert_apartment]
GO
CREATE TRIGGER trigger_insert_apartment
ON ApartmentInfo FOR INSERT
AS INSERT ApUser(ApartmentId, UserId ) SELECT i.ApartmentId, u.UserId FROM [User] AS u, inserted AS i
GO
IF EXISTS (SELECT * FROM sys.triggers WHERE object_id = OBJECT_ID(N'[dbo].[trigger_insert_user]'))
DROP TRIGGER [dbo].[trigger_insert_user]
GO
CREATE TRIGGER trigger_insert_user
ON [User] FOR INSERT
AS INSERT ApUser(ApartmentId,UserId ) SELECT a.ApartmentId, i.UserId FROM ApartmentInfo AS a, inserted AS i
GO
These two triggers will insert all apartments or users into the apinfo table when you add a new user or apartment, and if I understood your question that was what you wanted?
To address your question about what you'd do to associate apartments with users IF YOU WANTED TO LATER...
If you're restricting which apartments a user has access to view, I would NOT associate them individually to every user. BUT, if they're manually adding a "watch" on an apartment in your application, then this is ok to do. If you want to only show them a certain set of apartments, try to group them in a logical way if you can. So maybe have an ApartmentGroup lookup table:
ApartmentGroup(ApartmentGroupId (Int), ApartmentGroupName varchar(50))
and assign an ApartmentGroupId to each apartment. Then you can have a join table for ApUser and ApartmentGroup. That way you're not associating every apartment with every user.
However, if you want to add the apartment to each user still, then in your InsertApartment stored procedure, just insert it into the ApUser table as well.
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 need to define a table which basically will contain an Id for a user, and a second column which will list names of tables to which the user has access. I can't think of anyway to define any relationships here in case the original table names change. All the logic will be at the application level. However, I would like to be able to define some sort of constraints. How can I do this? Also, I am open to advice regarding any other way to do this.
I am really confused. Doesn't the grant command do exactly what you want? This assumes that the operations you want are database operations.
If you have a more customized set of operations, then you can keep track of table name changes via DDL triggers.
Here's a detailed code example of how to achieve this using RLS
USE tempdb;
GO
CREATE TABLE dbo.OKTable
(
OKTableID int IDENTITY(1,1) NOT NULL
CONSTRAINT PK_dbo_OKTable PRIMARY KEY,
SecuredInfo varchar(100)
);
GO
INSERT dbo.OKTable (SecuredInfo)
VALUES ('Very'), ('Secret'), ('Stuff');
GO
CREATE TABLE dbo.NotOKTable
(
NotOKTableID int IDENTITY(1,1) NOT NULL
CONSTRAINT PK_dbo_NotOKTable PRIMARY KEY,
SecuredInfo varchar(100)
);
GO
INSERT dbo.NotOKTable (SecuredInfo)
VALUES ('Other'), ('Important'), ('Things');
GO
CREATE SCHEMA [Security] AUTHORIZATION dbo;
GO
CREATE TABLE [Security].PermittedTableUsers
(
PermittedTableUsers int IDENTITY(1,1) NOT NULL
CONSTRAINT PK_Security_PermittedTableUsers
PRIMARY KEY,
UserName sysname,
SchemaName sysname,
TableName sysname
);
GO
INSERT [Security].PermittedTableUsers (UserName, SchemaName, TableName)
VALUES (N'dbo', N'dbo', 'OKTable');
GO
ALTER FUNCTION [Security].CheckUserAccess
(
#SchemaName AS sysname,
#TableName AS sysname
)
RETURNS TABLE
WITH SCHEMABINDING
AS
RETURN SELECT 1 AS CheckUserAccessOutcome
WHERE EXISTS (SELECT 1 FROM [Security].PermittedTableUsers AS ptu
WHERE ptu.UserName = USER_NAME()
AND ptu.SchemaName = #SchemaName
AND ptu.TableName = #TableName);
GO
CREATE SECURITY POLICY OKTableAccessFilter
ADD FILTER PREDICATE [Security].CheckUserAccess (N'dbo', N'OKTable')
ON dbo.OKTable
WITH (STATE = ON);
GO
CREATE SECURITY POLICY NotOKTableAccessFilter
ADD FILTER PREDICATE [Security].CheckUserAccess (N'dbo', N'NotOKTable')
ON dbo.NotOKTable
WITH (STATE = ON);
GO
SELECT * FROM dbo.OKTable;
SELECT * FROM dbo.NotOKTable;
GO
It's described more fully in this link:
https://blog.greglow.com/2019/10/10/sql-how-to-control-access-to-sql-server-tables-by-entries-in-another-table/
Since users are NOT SQL Server Logins, therefore, I guess you can use the DDL trigger to monitor table rename where you can change the table name in your custom security table. But I don't know if you can throw exception within this trigger to prevent table rename (simulating some type of constraint). Also it would be better if you store the table name in each line rather saving comma separated table names in 1 field.
If you can utilize SQL Logins then the Gordan's solution is also applicable, but sometimes you cannot create SQL Logins, in-case if you have different application databases along with hundreds of thousands of users.
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
I have a table with a column that I want to extract out and put into a separate table.
For example, lets say I have a table named Contacts. Contacts has a column named Name which stores a string. Now I want to pull out the names into another table named Name and link the Contact.Name column to the Id of the Name table.
I can only use SQL to do this. Any ideas on the best way to go about this?
Let me know if I can clarify anything, thanks!
[edit]
One problem is that different contacts can be tied to the same name. So when different contacts have the same name and it gets exported the Name table would only have one unique row for that name and all the contacts would point to that row. I guess this wouldn't make sense if I were actually working on a contact book, but I'm just using it to illustrate my problem.
CREATE TABLE Name (NameID int IDENTITY(1, 1), [Name] varchar(50))
INSERT INTO Name ([Name])
SELECT DISTINCT [Name]
FROM Contact
ALTER TABLE Contact
ADD COLUMN NameID int
UPDATE Contact
SET NameID = [Name].NameID
FROM Contact
INNER JOIN [Name]
ON Contact.[Name] = [Name].[Name]
ALTER TABLE Contact
DROP COLUMN [Name]
Then add foreign key constraint, etc.
Create the new table with a Foreign key that points back to the contact table. Then insert the names and contactids from the contact table into this new table. After that you can drop the "name" column from the contact table.
CREATE TABLE Name
(
ContactId int,
Name nvarchar(100)
);
INSERT Name(Name)
SELECT ContactId, Name From Contact;
ALTER TABLE Contact
DROP Column name;
EDIT: Since you have edited the question to mention that one name can be associated with multiple contacts, this changes things in the opposite way.
CREATE TABLE Name
(
NameId int IDENTITY,
Name nvarchar(100)
);
INSERT Name(Name)
SELECT DISTINCT Name From Contact;
ALTER TABLE Contact
ADD NameId int;
UPDATE c
SET c.NameId = n.NameId
FROM Contact c
JOIN Name n on n.Name = c.Name;
ALTER Table Contact
Drop Column Name;
NOTE: Make sure that you create the appropiate foreign key between the Contact and Name tables using the NameId on the Contact table and also create a UNIQUE constraint on the "name" column in the Name table.
insert into another_table( contact_id, name )
select id, name
from contacts;
insert into new_table (contact_id, name)
select min(id), name
from contacts
group by name;
This is one way of ensuring only one row per name - you can substitute other functions for min (like, for eg max).
I'm not too sure why you would want to do this, though. No matter what, you will end up with some contacts that don't have a name linked to them...
ALTER TABLE `Contacts` ADD `name_id` INT( 12 ) NOT NULL
ALTER TABLE `Name` ADD `Name` VARCHAR( 200 ) NOT NULL
INSERT INTO Name (id, name) SELECT id, Name FROM Contacts
ALTER TABLE `Contacts` DROP `Name`
The problem is the name_id field, which is filles with "0" and should be have the same value as the id in the Contacts-Table. Here you can use the LOOP or ITERATE statement (if you using MySQL).
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