Hi,
Suppose there is a composite index on a table, and in includes, for example 3 columns.
If I do a select using one of those three columns, will the select use the composite index? Will it aid in retrevial or should I create an index on the
individual column.
any thoughts on this would be appreciated.
thanks
Hello,
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.
I have the following confusion at hand:
I have a huge table named product.
I have the two different indexes:
index1: index keys =siteId, Catid (non-unique, non-clustered)
index2: index keys =siteid, Catid, date (non-unique, non-clustered)
Problem:
Do I really need these two separate indexes?? or is index2 enough
I'm working to improve performance on a database I've inherited, and there are several thousand indexes. I've got a list of ones which should definitely exist within the database, and I'm looking to strip out all the others and start fresh, though this list is still quite large (1000 or so).
Is there a way I can remove all the indexes that are not in my list without too much trouble? I.e. without having to manually go through them all individually. The list is currently in a csv file.
I'm looking to either automate the removal of indexes not in the list, or possibly to generate the Create statements for the indexes on the list and simply remove all indexes and then run these statements.
As an aside, when trying to list all indexes in the database, I've found various scripts to do this, but found they all seem to produce differing results. What is the best script to list all indexes?
I'm just now learning both SQL and ASP.NET, and I cannot seem to figure out how to build my data structure. I believe the answer to my problem is a composite key, but I cannot seem to get it to work. Here is an example. My database is of recorded dances, with exact locations within a ballroom. I believe I need 2 tablesTable #1 - DanceTableColumns: DanceID, Name, Description, TagsTable #2 - StepsTableColumns DanceID, StepID, longLocation, latLocation, Action, DescriptionWithin my ASP.NET application I want to be able to enter data about a dance, including metadata and a series of steps. The Dance and metadata content to be stored in DanceTable, and the series of moves stored in the StepsTable. I want the steps to be IDed as 1, 2, 3, 4...x with the first step being labled 1. and I want each dance to have it's own unique ID (DanceID). Right now I'm using "ExecuteNonQuery()" to add my data to my SQL database, and when I add new steps to the StepsTable SQL just finds the largest ID within StepID and increments it by one. So my steps are labeled as:Dance1:Step1, Step2, Step3, Step4Dance2:Step5, Step 6, Step7What I really want is (or I think what I want is) is a composite primary key.Dance1:Step1, Step2, Step3, Step4Dance2:Step1, Step2, Step3That way the StepID is used as both a primary key and it indicates the position within the dance. I guess I could just use a standard SQL table, let SQL auto generate StepID's and then add a new column called something like "StepNumber", but it just seems goofy to be generating a stepID and never using it. With composite keys (If I understand them) each step would have a unique key as a combination of the DanceID+StepID (AKA Dance 345, steps 1-10). I pull up data by searching for dances, and then sort by StepNumber, and those should all be unique...if I can figure out how to build them.
View 1 Replies View RelatedI have a table with a composite key formed by the unique combination of columns w, x, y, z
I'm trying to write an INSERT statement along the following lines
INSERT INTO myTable
(SELECT w, x, y, z FROM someTable) t1
WHERE (this is the part I'm stumped on - where the unique combination of w, x, y, z is NOT in myTable already)
Help would be appreciated. Can you use the NOT IN keyword on composite values?
How can I create a composite key (two primary keys for one table) using SQL Server 2005 Management Studio? Can I do it using the GUI, or do I have to write SQL code to do this? Thanks
View 7 Replies View RelatedMade an interesting discovery today - a column of data type Bit is not allowed to participate in composite key. Rather surprised.
I have a certain unique code that exhibits 2 unique states, which rendered the use of the boolean column, so the uniqueness goes <code>-1 and <code>-0. Is there any 'hack' so to speak to avoid using a Tinyint for the boolean column instead?
Can someone help me create a composite key on ms sql server through the enterprise manager?
Thanks,
Laura
The orininal design of my db (part of it...) is the following
A JOB has a Number and a Description.
Each JOB can have one or two TASKS (min one, max two). Each TASK is identified by the JOB it belongs to and an Index (unique only for the same JOB).
Each TASK has one an only one set of INFO1, one and only one set of INFO2, one and only one set of INFO3 etc.
A: JOB (JobNum [PK], JobDescription, ...)
B: TASK (JobNum [PK] [FKa], Index [PK], TaskDescription, ...)
C: INFO1 (JobNum [PK] [FKb], Index [PK] [FKb], ...)
D: INFO2 (JobNum [PK] [FKb], Index [PK] [FKb], ...)
(There is a reason to keep INFO1, 2 and 3 separate, because eachof them will be linked to different table. This might influence the answer to my real question.)
First of all, I wouldn't add any surrogate key for TASK, not to loose the logic behind; plus I'd put an ined on JonMum only, being Index equal to 1 or 2 only, so not selective.
The real question is about INFO1 (and 2, 3 etc.) table: should I leave JobNum and Index as PK (consider that the PK of INFo1 will be used as FK for another table), or should I use a surrogate key, like for eaxmple
C: INFO1 (Info1ID [PK], JobNum [FKb], Index [FKb], ...)
I don't really like this solution. Actually I'd prefer the following
C: INFO1 (Info1ID [PK], ...)
where Info1ID = JobNum + Index (+ = string concatenation).
Any suggestion?
Thanks
Hi folks, i need an advise.
I've a gerand table customers_orders table with customer_id and order_id.
Whenever we have to find orders, for customer, this table is involved. Hey; i know u'll be angry y the heck this gerand exist but i've to blame the older dudes then.
Now this table has composite clustered index; CUSTOMER_ID+ORDER_ID.
The tables have grown over GB size; i see HASH INNER JOIN rather than MERGE for the GEREND and CUSTOMER table join.
Is it good to use composite clustered index; or should i clustered one the columns in the GEREND and other to normal index. What performance impact it could be.
Howdy!
WHile designing a Database should one go for composite Primary Keys.
Or what are the Pros and Corns of Composite Primary Keys
Thanx
Hello, everyone:
I need to define composite PK and FK for a ERD. Could someone offer the methods that work with,
1. T-SQL
2. ERD
Thanks a lot.
ZYT
I've been facing this situation since long but today i am asking here. Suppose i have a following tables;
AdmissionInfo, AdmID, AdmDate, AdmFee etc.
SubjectInfo i.e. SubID, SubName, SubStatus etc.
The Result table is like this:
ResID, AdmID, SubID, TheoryMarks, PracticalMarks, ObtMarks, TotalMarks, ResultTerm, SubPercentage.
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?
View 5 Replies View RelatedThis 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?
Hello,
Does composite primary key affect performance on the table that contains the composite primary key or tables that references this table?
When composite primary key should be used?
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?
View 1 Replies View RelatedHi All, Can anyone tell me how to create a reference for composite key. For ex, I have created tblEmp table successfully. create tblEmp( empId varchar(100), RegId varchar(100), empname varchar(100),constraint pk_addprimary key(empId, RegId) ) And now, I am going to create another table which references the composite key.create table tblAccount( acctId varchar(100) primary key, empId varchar(100) references tblEmp(empId), RegId varchar(100) references tblEmp(RegId) ) But it gives error like Server: Msg 1776, Level 16, State 1, Line 1There are no primary or candidate keys in the referenced table 'tblEmp' that match the referencing column list in the foreign key 'FK__tbl'.Server: Msg 1750, Level 16, State 1, Line 1Could not create constraint. See previous errors. Could anyone please let me know how to create reference for composite key. Thanks in advance,Arun.
View 4 Replies View RelatedHi What is the difference between Candidate key , composite key and alternate key. I went through many websites but I didn't get examples. There were only definitions. Can anyone please tell me the site or blogs that elaborate this concept RegardsKaran
View 2 Replies View RelatedHi
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
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 several tables where I have used the command
distinct first_name, last_name, dob
to unduplicate.
I was wondering if I could create a new column in my table that combines the existing records for first_name, last_name and dob?
The requirement in to write a query which will return top 2 rows (in terms of lst_updt_timestamp column) for every combinations of cust_alias_nm, carrier_cd, acct_nbr columns.
Here I wrote a query which selects top 1 only.
Please help me to write to get the top 2nd along with the top 1st row.
select A.cust_alias_nm_id,
A.carrier_cd_id, A.acct_nbr_id,
sum(A.pd_clm_amt) clm_amt,
sum(A.pd_med_amt) med_amt,
sum(A.pd_exp_amt) exp_amt,
A.lst_updt_timestamp
from bal_load_stg A
group by A.cust_alias_nm_id, A.carrier_cd_id, A.acct_nbr_id, A.lst_updt_timestamp
having A.lst_updt_timestamp
in (
(select max(lst_updt_timestamp) from bal_load_stg B
where
A.cust_alias_nm_id = B.cust_alias_nm_id
and A.carrier_cd_id = B.carrier_cd_id
and A.acct_nbr_id = B.acct_nbr_id))
The output looks like:
cust_alias_nm_id carrier_cd_id acct_nbr_id clm_amt med_amt exp_amt lst_updt_timestamp
---------------- ------------- -------------- ---------------------------------------- ---------------------------------------- ---------------------------------------- ------------------------------------------------------
aaa 101 1234567891 500.00 500.00 500.00 2005-07-31 00:00:00.000
aaa 102 1234567891 500.00 500.00 500.00 2005-08-31 00:00:00.000
aaa 100 1234567890 700.00 700.00 700.00 2005-10-31 00:00:00.000
The desired output should look like:
cust_alias_nm carrier_cd acct_nbr clm_amt med_amt exp_amt lst_updt_timestamp
---------------- ------------- -------------- ---------------------------------------- ---------------------------------------- ----------------------------------------
aaa 100 1234567890 700.00 700.00 700.00 2005-10-31 00:00:00.000
aaa 100 1234567890 500.00 500.00 500.00 2005-08-31 00:00:00.000
aaa 102 1234567891 500.00 500.00 500.00 2005-08-31 00:00:00.000
aaa 101 1234567891 500.00 500.00 500.00 2005-07-31 00:00:00.000
aaa 101 1234567891 400.00 400.00 400.00 2005-05-31 00:00:00.000
All rows present in the table are
cust_alias_nm carrier_cd acct_nbr clm_amt med_amt exp_amt lst_updt_timestamp
---------------- ------------- -------------- ---------------------------------------- ---------------------------------------- ----------------------------------------
aaa 100 1234567890 700.00 700.00 700.00 2005-10-31 00:00:00.000
aaa 100 1234567890 500.00 500.00 500.00 2005-08-31 00:00:00.000
aaa 102 1234567891 500.00 500.00 500.00 2005-08-31 00:00:00.000
aaa 101 1234567891 500.00 500.00 500.00 2005-07-31 00:00:00.000
aaa 100 1234567890 400.00 400.00 400.00 2005-05-31 00:00:00.000
aaa 101 1234567891 400.00 400.00 400.00 2005-05-31 00:00:00.000
Thanks in advance.
Newbie question...
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.
Thanks in advance for the assistance.
I'm trying this
Code:
CREATE TABLE Rating
(ContentID int NOT NULL PRIMARY KEY REFERENCES Content_(ContentID),
UserID int NOT NULL PRIMARY KEY REFERENCES Usr(UserID),
rating tinyint DEFAULT 2,
LastRead smalldatetime NOT NULL DEFAULT CURRENT_TIMESTAMP)
And it is telling me this:
Msg 8110, Level 16, State 0, Line 14
Cannot add multiple PRIMARY KEY constraints to table 'Rating'.
So how do I combine two non-unique foreign keys, the combination of which is unique, into one primary key?
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:
A: JOB (JobNum [PK], DocReference, StartDate, EndDate, ...)
B: TASK (JobNum [PK] [FKa], Version [PK], Priority, ...)
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:
A: JOB (JobNum [PK], DocReference, StartDate, EndDate, ...)
B: TASK (JobNum [PK] [FKa], Version [PK], Priority, ...)
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...
A: JOB (JobNum [PK], DocReference, StartDate, EndDate, ...)
B: TASK (JobNum [PK] [FKa], Version [PK], Priority, ...)
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:
A: JOB (JobNum [PK], DocReference, StartDate, EndDate, ...)
B: TASK (TaskID [PK], JobNum [FKa], Version , Priority, ...)
C: TRANSLATION (TaskID [PK] [FKb], DueDate, ...)
D: TYPING (TaskID [PK] [FKb], DueDate, ...)
E: DISTRIBUTION (TaskID [PK] [FKb], Copies, ...)
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.
Hi All,
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.
How can I do this?
I need to select a row by the composite primary key. Then I need to insert a new row to the same table, but using different primary key. Is it possible to achieve this in one sql statement?
I am trying something of the like:
Hello,
Say I have a composite index, how can I programmatically find the components knowing only the table name?
For example, an index was created as follows:
CREATE UNIQUE INDEX [some_table_index] ON [some_table]([col1], [col2]) ON [PRIMARY]
Now, I'd like to get back 'col1' and 'col2' when I search for 'some_table'.
Thank you
Hi All!I would like to have a composite PK on 3 columns, one of them is nullCREATE TABLE TableA (ColA int NOT NULL ,ColB int NOT NULL ,ColC char (3) NULL ,......)GOALTER TABLE TableA ADDCONSTRAINT TableA_PK PRIMARY KEY CLUSTERED(ColA,ColB,ColC)GOSQL Server does not allow having a composite PK with one nullable column:What is wrong to have values?1,100,NULL1,200,ABC1,200,ABD.....Code in C applies to Values in B and for some values in B the code does not exist.I can work out and define a special Code:NEV(not existing value), but in general I do not understand this restriction.Thanks
View 3 Replies View RelatedI am trying to digest this logic, and have been unsuccessful so far. I am designing a package for incremental loads, but the destination table has a composite primary key on 2 columns, one of which is nullable. The source data comes from a SPROC. Uptill now, I have been banging my head trying to get this logic to work via the Lookup transform with a conditional split, but it doesn't work. Am I on the right track, or should I be using the SCD Wizard?
As a side note, I have been trying to work a solution using Andrew's blogpost on doing incremental loads: http://sqlblog.com/blogs/andy_leonard/archive/2007/07/09/ssis-design-pattern-incremental-loads.aspx
Thanks.
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?
Which is best way?
Thanks