Creating A Primary Key
Jun 3, 2008
Completely new to SQL so wondered if anyone could help with an issue I'm sure there is a simple answer too.
Need to create a Primary Key for an existing table. Now I have managed to create a new column called _ID, which set the contents to NULL. So populated the column with the number 1 so that I could set it to no null.
Now when I run the query:
ALTER TABLE tablename ADD PRIMARY KEY (_ID);
I get the error:
The CREATE UNIQUE INDEX statement terminated because a duplicate key was found for the object name 'dbo._DATACAPTURE' and the index name 'PK___DATACAPTURE__145C0A3F'. The duplicate key value is (1).
Which is obviously due to the repeated 1 in _ID.
So I am thinking I just need to run a query that fills the _ID with a unique number.
Any ideas how I do that?
Thanks for your help in advance.
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Feb 2, 2004
Hi
I'm trying to create a composite Primary Key on a table. This is the SQL I've written:
CREATE TABLE BookingItems
(
BookingID INT NOT NULL
REFERENCES Bookings(BookingID),
EquipmentTypeID INT NOT NULL
REFERENCES EquipmentType(EquipmentTypeID),
CONSTRAINT PK_BookingItems_id PRIMARY KEY
(BookingID, EquipmentTypeID)
)
Is this right? I'm trying to define a Primary Key made up of BookingID and EquipmentTypesID, which are both Foreign Keys as defined in the column definition.
Thanks
Jon
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Aug 19, 2002
Thanks to help from Ray Maio I have been able to create copies of various tables using the Select Into command.
Ray also responded that this command does does not transfer Primary Key and Index information.
I have attempted to create an index by using the following statement:
create nonclustered index SchoolIndx on wrestlerstest (School)
I did not get an error, but can't tell ift the index was created. The question is, how do I find out if
there is an index for the column School? Is there a command that will tell me. I'm just sending commands
to the server via a short .asp program and don't really know how to obtain a message back. Could I find the information
by browsing the
Thanks again in advance,
Greg Zafros
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Jun 29, 2006
Hi,
I need to create a new table in our database.
This table is not linked into the existing schema in anyway, so i'm not sure if I need a primary key or not.
either way, coudl anyone tell me how to create a primary key ni the CREATE TABLE statement.
I have tried searching but cannot find the answer.
many thanks,
Matt
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Oct 17, 2005
Hi all,I've spent hours trying to find the error in the following SQL 2000command:ALTER TABLE [ClientList] ADD CONSTRAINT [PK_ClientList] PRIMARY KEYCLUSTERED ([PhoneNo]) On [PRIMARY]Every time I try to "Execute" this from my (VB5) ODBC connection I get:Runtime error 3289;Syntax error in CONSTRAINT clauseFor the life of me I can see nothing wrong. I used Enterprise managerto create this statement, and I can create the primary key fine fromthere. The PhoneNo field does not allow NULLs.Everything is service-packed up to date. I have tried using[databasename].[dbo].[ClientList] and suchlike.I've tried to find a relevant manual, but my SQL Server developersguide suggests this should be ok and I can't see anything wrong in thebooks online.Can anybody please help?TIA
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Sep 17, 2007
I'd like to create a primary key value (incremental) within a trigger and set it in a primary key column.
Any idea anyone? Do I define my trigger as a On INSERT, Instead of INSERT? I tried both but it doesn't seem I'm doing things right.
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Jul 12, 2004
This question may be a little complicated.
I am building a DTS Package that is moving data from our webstore (written in house) to a Warehouse Management System(WMS - Turnkey) and I've encountered a problem. both pieces of software have an orders table and an Ordered_Items table, related by the order_ID (makes sense so far). Here is the problem. The primary key on the webstore's Ordered_Items table is a single column (basically an Identity variable), while the primary key on the WMS's Ordered_Items table is a dual column primary key, between the Order_ID and the Order_LineID, so the data should be stored like:
OrderID Order_LineID
1 1
2 1
2 2
2 3
3 1
3 2
4 1
Get the Idea? So I have to create this new Order_LineID column. How can I accomplish this with a SQL statement?
Thanks!!!!!
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May 30, 2000
I created table and also I define the primary key its okay
but when I generate the SQL script for that table its not
creating the primary key
CREATE TABLE [dbo].[table1] (
[emp_id] [int] NOT NULL ,
[emp_name] [char] (25) NULL ,
[emp_address] [nvarchar] (50) NULL
) ON [PRIMARY]
GO
PS: I want to use emp_id as primary key but its not defined in the sql script
Thankx a lot
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Mar 27, 2008
Hello everyone!
Even though I am not "new to SQL Server", my experience in working with it has ebbed and flowed, and working with SQL Server is not something that happens for me even on a monthly basis.
I work as an in-house programmer for a financial investment company and I have been asked to work on a database that is to hold financial data.
One of the requirements for the tables has been that the Primary Key should be [name_of_the_table] + [Identity].
So, for example, for table "tblEquities", the values of the Primary Key would be:
PK
-------
tblEquities1
tblEquities2
tblEquities3
tblEquities4
tblEquities5
My questions are:
1) Is it possible to achieve this by using just one column, as in defining a formula for the "Computed Column Specification" , something that would look like "'tblEquities' + Identity()"?
2) If the above is not possible, I assume it's much easier to just define a column as being Identity column and then create a 2nd computed column that would aggregate the name of the table with the value in the Identity column, so that I end up with a column holding the desired values? (I guess it would look something like
"'tblEquities' + [Identity]")
Also, I have been asked to find out what SQL 2005 have/offers, in term of guaranteeing referential integrity. Are the "Database Diagram", as well as the "Relationships" dialog box, the tools that would meet that criteria or does SQL 2005 contain other tools that would help in this regard?
Thank you!
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Jul 18, 2007
Hi,
I have created a very simple table. Here is the script:
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[IndexTable]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[IndexTable]
GO
CREATE TABLE [dbo].[IndexTable] (
[Id] [int] NOT NULL ,
[Code] [nvarchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL
) ON [PRIMARY]
GO
CREATE CLUSTERED INDEX [CusteredOnCode] ON [dbo].[IndexTable]([Id]) ON [PRIMARY]
GO
ALTER TABLE [dbo].[IndexTable] ADD
CONSTRAINT [PrimaryKeyOnId] PRIMARY KEY NONCLUSTERED
(
[Id]
) ON [PRIMARY]
GO
The records that i added are:
Id Code
1 a
2 b
3 aa
4 bb
Now when i query like
Select * from IndexTable
I expect the results as:
Id Code
1 a
3 aa
2 b
4 bb
as i have the clustered index on column Code.
But i m getting the results as:
Id Code
1 a
2 b
3 aa
4 bb
as per the primary key order that is a non clustered index.
Can anyone explain why it is happening?
Thanks
Nitin
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Feb 29, 2008
Hello,
I am trying to recreate a primary key that I dropped in a table....
I'm using a statement like
ALTER TABLE temp WITH NOCHECK add CONSTRAINT PK__tempkey PRIMARY KEY CLUSTERED
(
num,
store
)
But apparently the "store" column was created without a "not null" and it let it create the PK during the table creation but now it won't let me add the PK with that nullable column..
Does anyone know how to get it to use that column to create a primary key after the initial table creation?
Here is the error i get
Cannot define PRIMARY KEY constraint on nullable column in table
Thanks a lot
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Feb 1, 2008
I have a varchar column in a table, which is an unique key column. Now when I design this table should I use this column as a primary key or should I add one more Integer column as a primary key column for the performance?
One more point is, when ever I do a search on this table I will search based on that unique varchar column values only, so even then if I add new integer column just for Primary key I will not use this column for searching values.
With these information, can some body help me in deciding this?
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Jul 23, 2005
This is a fairly simple question, but what is the easiest way to:create a new numbered column (where value is simply the row number) inan existing table and setting it as a primary key?
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Mar 11, 2008
I currently have a website which is using ASP.NET 2.0, C#, and SQLServer 2005. The website will be used to enter grants for auniversity. When a new grant is entered, I need to generate a primarykey. The primary key will need to follow the format: Two digit forfiscal year, then number of the grant for that year. Example:Year 08 and 14th grant of the year would be: 0814How can I implement this. Right now, I have a "New Grant.aspx" pagewith a Submit button. I am guessing the date is going to be formattedin C#. How can I check what the last primary key in the database is?Also, it seems to me that SQL Server insists that the primary key be32 bits long, however my primary key will only be 4. How can Ioverride this? Thanks.
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Jul 16, 2007
Hey everyone,
I have just started getting into to SQL and am completely brand new to the whole concepts of relational databases. Someone on this forum pointed to the MSDN videos on LEARNVISUALSTUDIO.NET which have been very helpful. Unfortunately while learning about relational databases and looking at the program that I want to design and make using them, I have run into a pretty big wall, concerning the primary key and foreign key.
For my program, I am trying to save an object, and lets say the base class is SLIDE. Now SLIDE will store basically most of the information that I will ever want to store, such as timeCreated and mainText and slideID(primarykey). But there are other classes that derive from slide that will store just a bit more information than that because of what they are. Lets say there is a class derived from SLIDE called PERSON that stores its parentNode, which is to say something that this slide specifically belongs to and has a reference to. Now the tricky part is that in this program, every single slide can have a reference to another slide, that you would see displayed and that you could just click on and view if you wanted to.
Now relating what I just told about the classes in my program to a relation database standpoint is what confuses me. If I make a table SLIDE, it would hold incomplete data about the PERSON object, because that object has more data than SLIDE has. The answer to this was to make another table called PERSON, which would have more columns. But now we arrive at the big problem: The primary key called maybe SLIDEID would be different in this new PERSON table than in the other table called SLIDE (or any other derived class). Therefore the link between these tables is messed up. In my object orientated mind I am thinking of static class variables that would still stay constant for derived classes, so that when I make a PERSON slide it will increment off of the primary key of the SLIDE table. In other words, is there some sort of super TABLE that you can derive from, like an abstract class, where the primary keys of other tables can build off of because they will be used as the same type of reference to eachother.
If none of this made sense to the reader, I am greatly sorry. I do not really know what else I can say to convey to you the problem I have. Maybe its because I am so used to object orientated languages that this is making it so difficult to explain. If however you do understand what I am talking about, please think about it and help me find a solution to this problem. I am not an experienced programmer, but I do very much enjoy it and I am very excited about starting to make this program, and I have learned that before I start coding it is very important to have a very firm design in mind first.
Thank your for reading,
Jeremy
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Feb 1, 2007
Hi,
I am trying to execute following sql script in sql-server 2000 query analyzer
CREATE TABLE user_courses (user_id varchar(30) NOT NULL PRIMARY KEY,
course_id varchar(10) NOT NULL PRIMARY KEY)
Its give's me following error :-
Cannot specify multiple primary key constraint
Hence I am not able to ceate table with multiple primary keys. So can any one tell me how to get this done?.
Secondly, Primary key must be unique i.e duplicate values are not allowed in P.K field. But in this case since I am declaring two fileds as primary keys.
Will it allow me to have following records in the user_courses table?
user_id(P.K) course_id(P.K)
bob CRS235
alice CRS235
Tim CRS235
tom CRS635
So, if we consider both the fields as primary keys together than I am not voilating Uniqueness constraint. But, if I look at course_id alone then I am voilating uniqeness property?
Thanks,
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Jun 26, 2014
Discuss the following sql query with respect to performance in an applicaiton involving more number of concurrent users creating and deleting records. The objective is to create continuous primary key integer values.
Table name: SitePage
Column DataType
--------- -----------
PageID BigINT
PageName nchar(10)
Query to insert new record
DECLARE @intFlag INT
SET @intFlag = 0
WHILE (@intFlag =0)
BEGIN
BEGIN TRY
[Code] ....
We don't want to use auto increment integer value for primary key because of the following reason
[URL] .....
We also don't want to use SEQUENCE as we have to create 50 sequence for 50 tables
We can't do trace flag 272
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Apr 30, 2015
Environment: Microsoft SQL Server Standard Edition (64-bit), 10.0.5520.0
I was doing a code review for another developer and came across this code:
CREATE TABLE dbo.#ABC
(
ReportRunTime DATETIME
,SourceID VARCHAR(3)
,VisitID VARCHAR(30)
,BaseID VARCHAR(25)
[Code] ....
This EXECUTES with no error or warning message.However, if I change this to CREATE the PK in an ALTER TABLE statement, I get the (expected by me) error:
CREATE TABLE dbo.#ABC
(
ReportRunTime DATETIME
,SourceID VARCHAR(3)
,VisitID VARCHAR(30)
,BaseID VARCHAR(25)
,OccurrenceSeqID INT
[code]...
==> Msg 8111, Level 16, State 1, Line 17 Cannot define PRIMARY KEY constraint on nullable column in table '#ABC'.
==> Msg 1750, Level 16, State 0, Line 17 Could not create constraint. See previous errors.
(note: As the #ABC table is an actual copy of a few of the columns in a "permanent" table, I will likely change the definition as follows such that the columns are defined to match the names / datatypes / NULLability:
SELECT TOP 0
CAST('01-01-1980' AS DATETIME) AS [ReportRunTime]
,SourceID
,VisitID
,BaseID
,OccurrenceSeqID
[Code] .....
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Apr 11, 2006
Hello again,
I'm going through my tables and rewriting them so that I can create relationship-based constraints and create foreign keys among my tables. I didn't have a problem with a few of the tables but I seem to have come across a slightly confusing hiccup.
Here's the query for my Classes table:
Code:
CREATE TABLE Classes
(
class_id
INT
IDENTITY
PRIMARY KEY
NOT NULL,
teacher_id
INT
NOT NULL,
class_title
VARCHAR(50)
NOT NULL,
class_grade
SMALLINT
NOT NULL
DEFAULT 6,
class_tardies
SMALLINT
NOT NULL
DEFAULT 0,
class_absences
SMALLINT
NOT NULL
DEFAULT 0,
CONSTRAINT Teacher_instructs_ClassFKIndex1 FOREIGN KEY (teacher_id)
REFERENCES Users (user_id)
)
This statement runs without problems and I Create the relationship with my Users table just fine, having renamed it to teacher_id. I have a 1:n relationship between users and tables AND an n:m relationship because a user can be a student or a teacher, the difference is one field, user_type, which denotes what type of user a person is. In any case, the relationship that's 1:n from users to classes is that of the teacher instructing the class. The problem exists when I run my query for the intermediary table between the class and the gradebook:
Code:
CREATE TABLE Classes_have_Grades
(
class_id
INT
PRIMARY KEY
NOT NULL,
teacher_id
INT
NOT NULL,
grade_id
INT
NOT NULL,
CONSTRAINT Grades_for_ClassesFKIndex1 FOREIGN KEY (grade_id)
REFERENCES Grades (grade_id),
CONSTRAINT Classes_have_gradesFKIndex2 FOREIGN KEY (class_id, teacher_id)
REFERENCES Classes (class_id, teacher_id)
)
Query Analyzer spits out: Quote: Originally Posted by Query Analyzer There are no primary or candidate keys in the referenced table 'Classes' that match the referencing column list in the foreign key 'Classes_have_gradesFKIndex2'. Now, I know in SQL Server 2000 you can only have one primary key. Does that mean I can have a multi-columned Primary key (which is in fact what I would like) or does that mean that just one field can be a primary key and that a table can have only the one primary key?
In addition, what is a "candidate" key? Will making the other fields "Candidate" keys solve my problem?
Thank you for your assistance.
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Jul 16, 2014
what the best practice is for creating indexes on columns that are foreign keys to the primary keys of other tables. For example:
[Schools] [Students]
---------------- -----------------
| SchoolId PK|<-. | StudentId PK|
| SchoolName | '--| SchoolId |
---------------- | StudentName |
-----------------
The foreign key above is as:
ALTER TABLE [Students] WITH CHECK ADD CONSTRAINT [FK_Students_Schools]
FOREIGN KEY([SchoolId]) REFERENCES [Schools] ([SchoolId])
What kind of index would ensure best performance for INSERTs/UPDATEs, so that SQL Server can most efficiently check the FK constraints? Would it be simply:
CREATE INDEX IX_Students_SchlId ON Students (SchoolId)
Or
CREATE INDEX IX_Students_SchlId ON Students (SchoolId, StudentId)
In other words, what's best practice for adding an index which best supports a Foreign Key constraint?
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Jan 11, 2007
Uma writes "Hi Dear,
I have A Table , Which Primary key consists of 6 columns.
total Number of Columns in the table are 16. Now i Want to Convert my Composite Primary key into simple primary key.there are already 2200 records in the table and no referential integrity (foriegn key ) exist.
may i convert Composite Primary key into simple primary key in thr table like this.
Thanks,
Uma"
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Aug 28, 2002
Hi all,
Can anyone suggest me on Adding primary key to a table which has already a primary key.
Thanks,
Jeyam
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Aug 13, 2007
Hi,
I have recently been looking at a database and wondered if anyone can tell me what the advantages are supporting a unique collumn, which can essentially be seen as the primary key, with an identity seed integer primary key.
For example:
id [unique integer auto incremented primary key - not null],
ClientCode [unique index varchar - not null],
name [varchar null],
surname [varchar null]
isn't it just better to use ClientCode as the primary key straight of because when one references the above table, it can be done easier with the ClientCode since you dont have to do a lookup on the ClientCode everytime.
Regards
Mike
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Feb 4, 2015
We have a table, which has one clustered index and one non clustered index(primary key). I want to drop the existing clustered index and make the primary key as clustered. Is there any easy way to do that. Will Drop_Existing support on this matter?
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Jan 28, 2004
Hi all
I have the following table
CREATE TABLE [dbo].[property_instance] (
[property_instance_id] [int] IDENTITY (1, 1) NOT NULL ,
[application_id] [int] NOT NULL ,
[owner_id] [nvarchar] (100) NOT NULL ,
[property_id] [int] NOT NULL ,
[owner_type_id] [int] NOT NULL ,
[property_value] [ntext] NOT NULL ,
[date_created] [datetime] NOT NULL ,
[date_modified] [datetime] NULL
)
I have created an 'artificial' primary key, property_instance_id. The 'true' primary key is application_id, owner_id, property_id and owner_type_id
In this specific instance
- property_instance_id will never be a foreign key into another table
- queries will generally use application_id, owner_id, property_id and owner_type_id in the WHERE clause when searching for a particular row
- Once inserted, none of the application_id, owner_id, property_id or owner_type_id columns will ever be modified
I generally like to create artificial primary keys whenever the primary key would otherwise consist of more than 2 columns.
What do people think the advantages and disadvantages of each technique are? Do you recommend I go with the existing model, or should I remove the artificial primary key column and just go with a 4 column primary key for this table?
Thanks Matt
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Jan 28, 2008
Hi,
If I want to automatically insert a record which has default value in a table,
how can I create the trigger?
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Jul 11, 2007
I am in need of creating a new user for stored procedures execution say sa (to whom i am in need of creating under my user defined db)
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Aug 31, 2006
Hello all,I'm taking over a project from another developer and i've run into a bit of a problem. This developer had a bad habit of not using primary keys when designing various databases used by his programs. So now i've got approx 1000 tables all of which do not have primary keys assigned. Does anyone know of a tsql script that i can run that will loop through each table and add a primary key field?Thanks in advance?Richard M.
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Aug 16, 2007
I have a Department Table.
Can any one tell me its Primary Key.
I have the order
AutoNumber, D + AutoNumber, Code,
Can you help me regarding this.
Because some people never like to use AutoNumber.
That's why I am confused.
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Nov 8, 2007
Hi..
I'm going to build database of university, but I have problem with primaru key,
This is the situation:
there are many faculities and each one has many departments,
each department has many courses,
each course has many sections..
The problem:
I want to make those fields in the same table and make the primary key generate from other fields,
(i.e)
I want the faculity be integer from 4 digit "Example the first faculity start with 1000 the second 2000 and so on" and the the department of each faculity will generate its value from the faculity number+interger number from 3digit "Example the department of the first faculity start with 1100 and the second on will be 1200 and so on "
the same thing will repeate for courses and sections so the sectionsID will be the primary key.
Do you know hoew this idea can be implement by SQL server 2005?
Please help me as soon as possible.
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Mar 23, 2005
A column will be Primary Key. Others are B and C. I want A will contain B and C. I mean B data is X, C data is Y, A will be XY. How can i do this? Can i set in MSSQL or need ASP.NET?
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Dec 1, 1998
Heya,
I'm trying to setup a Primary Key on a SQL 6.5 database.
Is there a way to do this? When I hit advanced, it asks for me to select a field for the primary key, but it doesnt list fields to selct from, and I cant type it in.
Thanks for your help,
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Jul 8, 2004
Hi All,
Using DTS i have imported the data from sybase to MS SQL server and all the data and tables were imported correctly.But the primary keys are not marked why is it like this?
This is not a one time job and this is meant to be for the customers also.I cannot ask the customers to mark the primary keys themselves. Is there a way to get the keys also.While doing DTS I have marked all the options correctly.
Please help.
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