I have a table which has a composite primary key consisting of four columns, one of them being a datetime called Day.
The nice thing afaik with this composite key is that it prevents duplicate entries in the table for any given day. But the problem is probably two-fold
1. multiple columns need to be used for joins and I think this might degrade performance? 2. in client applications such as asp.net these primary keys must be sent in the query string and the query string becomes long and a little bit unmanagable.
A possible solutions I'm thinking of is dropping the existing primary key and creating a new identity column and a composite unique index on the columns from the existing composite key.
I would like to have some tips, recommendations and alternatives for what I should do in this case.
NOTE: I am not interested in any responses that want to argue the use of a unique ID field and autonumbering as the PK. It is quite clear from the forums that this subject is a polarizing one. This question is for those who follow text-book design practices and believe that a composite primary key should be used when it is available. I want to be one of them for the time being.
SYNOPSIS: I have three tables, TestSummary, TestDetails, and Steps.
The TestSummary table looks like this:
Create table TestSummary ( TestSummaryID int identity primary key, ... SequenceID int not null )
It contains the date and time of the test, the serial number, the part number, the test operator's name, and the ID of the sequence of steps used during the test. It uses a unique ID field for the primary key.
The TestDetails table looks like this:
Create table TestDetails ( TestDetailsID int identity primary key, TestSummaryID int not null, StepID int not null, ... )
It contains the details of the test like voltage readings, current readings, temperature, etc., one record per reading. It also contains the step number of the test sequence specified in the TestSummary table.
The Steps table looks like this:
Create table Steps ( SequenceID int not null, StepID int not null, Function int not null Primary key (SequenceID, StepID) )
It contains a list of all of the functions to be performed on the device under test by sequence number and the step number within the sequence.
When I try to establish a relation between TestSummary.SequenceID and Steps.SequenceID, SQL Server flags an error because TestSummary.SequenceID and Steps.SequenceID:Steps.StepID do not match.
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.
ResID is PK, AdmID and SubID are Foreign Keys, right. Now What i want to ask/ learn that Am i suppose to combine ResID, AdmID and SubID as a composite PK or should i simply make the ResID as PK and other 2 be there as FK? When do we really need to use Composite PK and using it a good thing or not?
i have a master table with around 15 columns and i am trying to findthe appropriate primary keys and indexes for the table.To make the records unique, i need to include two datetime columns (start and end dates ) and two integer columns ( attributes of therecord ) to make up a composite primary key. Both of these fourcolumns are found in the WHERE clause of my queries.Is it acceptable in the view of performance and how should i createthe indexes?
This is really not a T_SQL question but there's no good category for it so I thought I'd just put it here.
I have a table that will contain a large amoutn of data in one field, and every piece of this data is uniquely identitied by six other attributes, that is, six other fields (e.g. user_ID, type_ID, year, country, state, item_ID). I can either make these six fields into a composite primary key, or add an additonal field (say an identity column) as the primary key and add a unique constraint on these six fields. What are the pros and cons of both designs? The one data field is of nvarchar(2000) type and the table is likely to have 50 million+ rows in a couple of years of real use.
This table is not referenced by any other tables so whatever the primary key is, there's no FK reference. However, there could be FK references to this table in the future. Does the FK possibility make a difference in the design considerations?
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.
I have two tables (categories & listings) which create a many-to-many relationship.
I have created an interim table with the primary keys from each table as a composite primary key...(cat_id & list_id).
How does the interim table get populated with the id's?
When I do an insert statement to insert data into the categories table, the cat_id field is automatically generated...same with the listings table, but when (and how) does the primary key data get into the interim table.
My previous post was not really clear, so I'll try again with a (hopefully) better (even if longer) example...
Consider the following...
A JOB describes the processment of a document. Each document can exist in two versions: English and French. A JOB can have 1 or 2 TASK, each describing the processement of either the English or French version. So we have the following:
that is there is an identifying 1:M (where maxium allowed for M is 2) relationship between JOB and TASK; TASK being identified by JobNum and Version (where the domain for Version is {E, F}).
Each TASK may require a TRANSLATION sub_task. Each TASK may require a TYPING sub_task. Each TASK may require a DISTRIBUTION sub_task.
For example, for a given doc, the English TASK requires TRANSLATION and DISTRIBUTION, while the French only DISTRIBUTION.
That is, there is a 1:1 not-required relationship between TASK and TRANSLATION, TYPING and DISTRIBUTION. So we have the following:
C: TRANSLATION (JobNum [PK] [FKb], Version [PK] [FKb], DueDate, ...) D: TYPING (JobNum [PK] [FKb], Version [PK] [FKb], DueDate, ...) E: DISTRIBUTION (JobNum [PK] [FKb], Version [PK] [FKb], Copies, ...)
As you can see I am using the PK of TASK as FK and PK for each of the three SUB_TASKs.
To complicate things, each SUB_TASK has one or more assignments. The assignments for each SUB_TASK records different information from the others. So we have...
C: TRANSLATION (JobNum [PK] [FKb], Version [PK] [FKb], DueDate, ...) D: TYPING (JobNum [PK] [FKb], Version [PK] [FKb], DueDate, ...) E: DISTRIBUTION (JobNum [PK] [FKb], Version [PK] [FKb], Copies, ...)
F: TRA_ASSIGN (JobNum [PK] [FKc], Version [PK] [FKc], Index [PK], Translator, ...) G: TYP_ASSIGN (JobNum [PK] [FKd], Version [PK] [FKd], Index [PK], Typyst, ...) H: REP_ASSIGN (JobNum [PK] [FKe], Version [PK] [FKe], Index [PK], Pages, ...)
that is there is an identifying 1:M relationship between each SUB_TASK and its ASSIGNMENTs, each ASSIGNMENT being identified by the SUB_TASK it belongs to and an Index.
I wish I could send a pic of the ER diagram...
Maybe there is another and better way to model this: if so, any suggestion?
Given this model, should I use for TRANSLATION, TYPING and DISTRIBUTION a surrogate key, instead of using the composite key, like for example:
C: TRANSLATION (TranslationID [PK], JobNum [FKb], Version [FKb], DueDate, ...) D: TYPING (TypingID [PK], JobNum [FKb], Version [FKb], DueDate, ...) E: DISTRIBUTION (DistributionID [PK], JobNum [FKb], Version [FKb], Copies, ...)
this will "improve" the ASSIGNMENTs tables:
F: TRA_ASSIGN (TranslationID [PK] [FKc], Index [PK], Translator, ...) G: TYP_ASSIGN (TypingID [PK] [FKd], Index [PK], Typyst, ...) H: REP_ASSIGN (DistributionID [PK] [FKe], Index [PK], Pages, ...)
I could even go further using a surrogate key even for TASK, which leads me to the following:
F: TRA_ASSIGN (TaskID [PK] [FKc], Index [PK], Translator, ...) G: TYP_ASSIGN (TaskID [PK] [FKd], Index [PK], Typyst, ...) H: REP_ASSIGN (TaskID [PK] [FKe], Index [PK], Pages, ...)
I don't really like this second solution, but I'm still not sure about the first solution, the one with the surrogate key only in the SUB_TASks tables.
I have a table that has 3 columns, two of them make a composite primary key. The table is populated with data. What I need to do is to add a third column to a composite primary key. I have tried to do that with the following command:
alter table databasesize add constraint pk_dbsize primary key (dbid)
But I get the error message:
Table 'databasesize' already has a primary key defined on it.
Hi, In my table1, I have a composite primary key ssn+firstname+lastname. In table2 I have ssn, firstname, lastname, col1. In table2 I want to create a foreign key which references table1 primary key? table1 and table2 has the primary, foreign key relationships. Still table2 need primary key. In table2 Can I make the ssn+Firstname+Lastname as primary key? or one column id as auto increment?
What I need to achieve is - everytime that a new line is inserted into an orderlines table part of the primary key will be the OrderId and the OrderLineId should be auto-incremented from 1 for each OrderId in the OrderLines table.
I know i can do this manually in my program, but i'm just wondering if theres a way to achive this in SQL Server?
I have two tables: table 1 and table 2. The primary key of table is composite key of two collumns and table 2 is the child of parent table 1. Is it possible to create / define a foreign key constraint using a composite primary key?
create table z ( eno int, deptno char(2), ename varchar(5), constraint pk_eno_deptno primary Key(eno,deptno) ) and I tried to establish a foreign key based on the above defined table. It's giving error,
create table z_dup ( eno int FOREIGN KEY REFERENCES z(eno), deptno char(2) ) go
Error:- ***** There are no primary or candidate keys in the referenced table 'z' that match the referencing column list in the foreign key 'FK__z_dup__eno__18CE1BA6'.Could not create constraint. See previous errors.
Even I tried to create a foreign key like the following,
create table z_dup ( eno int FOREIGN KEY REFERENCES z(eno,deptno), deptno char(2) ) go
Error:- ******** More than one key specified in column level FOREIGN KEY constraint, table 'z_dup'.
Can anyone please help me to create a foreign key relation with the base table.
Hi, i want to make a reference from a table on itself. The table has a composite Primary Key. But I just want to refernce the TEstCaseID. So whats wrong? Can anyone help me?
We have scenario like this .the source table have composite primary key columns c1,c2,c3,c4.c5,c6 .when we move the records to destination .we have to check columns (c1+ c2 + c3 + c4 + c5 + c6) combination exist in the destination. if the combination exist then we should do a update else we need to do a Insert . how to achive this .we have tryed useing conditional split which is working only for a single Primary key . can any one help us .
my stored procedure have one table variable (@t_Replenishment_Rpt).I want to create an Index on this table variable.please advise any of them in this loop... below is my table variable and I need to create 3 indexes on this...
I want to created composite primary key using MS SQL Server Enterprise Manager Interface. I want to use Interface instead of writing it in CREATE Table statement. I was able to create foreign key using this Interface using the "Manage Relationship" option. But cannot find how to add primary key consisting of two fields. Any help regarding this is highly appreciated.
The table above is my users table. It allows for a user to be at multiple sites or multiple locations within a single site or multiple sites. Would it be wise to use a auto incrementing primary key instead of the 3 column composite key? The reason I ask is because if I am referencing this SU table (which I will be a lot), a lot more data would be replicated to the tables which have the foreign key to this table, right? But if I used a single incrementing column as the primary key, only a small integer would be used as the foreign key, saving space?Does this make sense?
Hi all, well i want to have an web-based database application in which in an single webform , i need to insert the values to 5 different tables. here empid is primary key (PK) in one table and in the rest of the tables its an Foreign Key(FK) my question is, how can i create these tables with composite key? ie, i want to creat an table which will have FK and as well another key which both will uniquely idenitfies a row. Well i am using SQL server 2000 and i wish to create these tables using the enterprise manager. here are the tables 1) empidtable empid,fname,lname 2)empcountrytable empid,country 3)empvisatable empid,visa 4)empdoctable empid,doc 5)empfile empid,filename,filecontenttype,filesize,filedata Plz do help me thanx in advance
I have three tables that are important here, a 'Plant' table a 'Spindle' table and a 'PlantSpindle' table. The 'PlantSpindle' is comprised of a PlantID and a SpindleID acting as the Primary Key for the table with no other fields.
I have an aspx page that captures the appropriate data to create an entry in the Spindle table. Depending on the user, I will know which plantID they are associated with via a querystring. In my storedproc I insert the data from the webform into the Spindle table but get stuck when I try to also insert the record into the PlantSpindle table with the PlantID I have retrieved via the querystring and the SpindleID of the spindle record the user just created. Basically, I am having trouble retrieving that SpindleID.
Here is what I have in my storedProc (truncated for brevity).
AS SET NOCOUNT ON INSERT INTO Spindle (plantHWG, spindleNumber, spindleDateInstalled, spindleDateRemoved, spindleDurationMonths, spindleBearingDesignNumber, spindleArbor, spindleFrontSealDesign, spindleFrontBearing, spindleRearBearing, spindleRearSealDesign, spindleNotes) VALUES (@plantHWG, @spindleNumber, @spindleDateInstalled, @spindleDateRemoved, @spindleDurationMonths, @spindleBearingDesignNumber, @spindleArbor, @spindleFrontSealDesign, @spindleFrontBearing, @spindleRearBearing, @spindleRearSealDesign, @spindleNotes)
SET @spindleID = (SELECT @@Identity FROM Spindle)
INSERT INTO PlantSpindle (plantID, SpindleID)
VALUES (@plantID, @SpindleID)
I have guessed at a few different solutions but still come up with Procedure 'InsertSpindle' expects parameter '@spindleID', which was not supplied when I execute the procedure.
I am trying to add indexes to my table data types and have realized that I can only add primary keys. So, I am hoping there is a way to add a composite primary key, but I am not having any success. I have tried the following:
We have an entity such as a documentSearchKey that contains attribtes about a particular document. This document can have 1-N number of search keys or attributes. The classic Employee Table is a good example for a horizontal listing of attributes (fname, lname, SS#, address, etc.) because the employee entity has a "fixed" number of attributes so we can add columns across.
For the documentSearchKey entity attributes can be considered search keys or where clause values. The documentSearchKey entity has variable number of attributes (docType A has 5 keys, docType B has 15 keys, etc) For this example each docType lives inside its on table so there is not a problem with mixing a variable number attributes inside the same table i.e. we will assume this table has 20 keys vertical or 20 columns horizontal as defined below.
The problem is whether or not to add 20 columns across or to add 3 columns and create a non-normalized DB so additional keys can be added at will.
The proposed table now contains 3 columns (docID, KeyID, KeyValue). Of course, 10 keys for 1 million records create 10 million rows Versus the traditional table with 1 million records always has 1 million records(keys are cols) where some columns contain blanks or nulls.
Which design is better in terms of searching and performance? Also, books and links are welcome as well. This is a specific question to a production issue.