SQL 2012 :: Database Design - Choosing A Primary Key?
Apr 30, 2014
choosing a primary key for the database which i am designing.
I have few tables which contains 5 -15 fields out of it 3 - 9 columns combined to form the uniqueness of the row.
All are un-related tables. Three parent tables connect with 20 child non-related child tables.
I believe it would not be a wise choice to choose 3 to 9 fields for primary key. But if i use an auto increment as a key will there be of any use as it might never be used to fetch rows. Then why do i still have to go with that?
Or Is it ok to create a primary key of upto 5 attributes?
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Jul 20, 2005
Hello group:I've done alot of reading on this subject somewhat and have found thatmany people have many different opinions on this subject. My questioncenters mainly around using a lookup table to enable users to select apre-defined list of values.I have developed a practice myself of avoiding AutoNumber type datafields for primary keys where the primary key will be related to achild table. Nevertheless, what do most users do with lookup tables?My thoughts are to create a small key value for each value in thelookup table. For example:I might have a Carriers table which shows a list of carriers that Imight ship an order by. One of the entries may be 'Air Freight -Overnight', or 'Air Freight - 2nd Day Air'. I've seen a few exampleswhere the primary key field for each entry like these would beautonumber, or at least, a numeric value. What I like to do is createmy own key, like for 'Air Freight - Overnight', I might use 'AFO' forthe key, and for 'Air Freight - 2nd Day Air', I might use 'AF2'. Anythoughts on this? Mine are that even tho the users may never see thisvalue - I, as the developer will see it and I tend to prefer a keyvalue based on real data that means something other than anauto-incremented number. In referencing the well-known Northwind.mdbdatabase, I noticed their Categories table used a number field value,like 1, 2, 3....etc, but their customers table used values like'ALFKI' to represent their key values.What are some other thoughts out there? I'm working with Accesscurrently, but this project is about to move to SQL Server.James
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Apr 5, 2005
Hi!
I have seen two approaches to primary keys. First one - and it is like
default - is to use surrogate key as primary key. For each table I will
create some autonumeric field hat cannot be changed once it has value.
Some materials refer to this key also as technical primary key. I
design my databases this way usually.
The other approach is to create primary key of fields that make primary
key on database logical model. This approach is not so popular and has
some side effects like a little bit clumpsy looking joins and
unconvenient use in applications.
Question: What is the main idea behind second approach? Or how explain their preference database designers who are using second approach?
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Jun 11, 2014
I would like to do partitioning one of my client, but that primary database is participating in log shipping.
If I do partitioning on primary, automatically apply those changes on secondary db? if not, what is the way?
Note: I am adding new filegroups and ndf file in different drives on primary database.
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Mar 1, 2015
In always on docs in msdn they mention only about backup of secondary.. explain the backup of primary or how logs are managed in primary database. My doubt is a normal database in full recovery mode the log file will grow if we didnt take proper log backup,how the same is managed in primary in Always On.
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May 14, 2015
I am using sql2012 se and we want to use couchbase to store some data as documents. So the database will be Hybrid(partly SQLServer and Partly couchbase). However the database is still in the design phase. What are the things that we should keep in mind when designing this database from a design perspective? Our database which was completely SQLServer based(RDBMS) was using GUIDs everywhere based off NEWID() and prime goal is to get rid of GUIDs for the most part.
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Jun 5, 2014
We have a Silverlight based application which currently supports only one production version. Idea is to support three concurrent versions of the same application and user will switch to the newer versions based on their interest or they can still continue with the older version.
We still have to use the existing database for all these three versions.
What is the best way to architect this so that we can differentiate the code between the versions and still keep the data in sync and run all the versions in parallel.
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Jun 4, 2006
Greetings!
I am purchasing a new/first server and could use some help with the details.
I am purchasing the server with the intent of managing a large database that will be quite extensive and requires a good amount of processing power. I have decided to go with windows server 2003 and SQL Server 2000 as a database. Within next year I hope to have this database directly flowing to a website that I could possibly be hosting as well as 2-3 offsite employess logging into the system remotely.
I would say my biggest question is whether or not to choose the raid 1 configuration or the raid 5. I want to be able to have the Hard drives mirror eachother. I was thinking of going with three hard drives but im not really sure if I would even need that setup. With that, I will just show my current system:
Dell poweredge 1800
3.0 ghz xeon
2 gb memory
sata 1 raid
cerc 6-Channel sata raid controller
160 gb hd x 2
onboard NIC network adapter
Im going price savvy on this one so no ups redundant, power supplies, or tape backup. Although I am open to any suggestions.
Definately appreciate any help with this as I have been hard pressed to find some quality reseller help. They just want to throw the biggest and baddest thing at me.
Thanks!
-Shawn
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Oct 13, 2004
hi,
I need to choose a database based on the following criteria (using .NET app):
1) a light but fully functional database, preferably with the support of store proc and constraints, less than 8000 transaction a day.
2) portable or the database can be export/import very easily
3) reliable and stable
4) least maintenance
I have two db in my mind, Access and MSDE?
Does anyone have some hand-ons experience on the above two? Or any other better suggestions?
Any advice is appreciated.
thanks,
bryan
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Dec 16, 2007
Lets assume database A is production, B is copy. SQL Server 2005 sp2, SQL CE 3.5
Database A has a variety of transactions against it 24x7
Database B (the copy) is for reporting and as a source of merge replication for SQL CE instances
Merge replication and reporting is used 24x7 as well
I have the following requirements:
Maintain an up to date copy of the production database (need not be up to the minute, could be hourly, even daily update)
Database B is read-only. The merge replication is NOT bi-directional.
Here is the caveat (which I think prohibits using some solutions to this problem):
The production application accomplishes much of it's functionality with in-memory copies of records. I have no control over the production application. When it works against the database, it sort of does a 'withdrawal-deposit' scenario. (to the best of my knowledge it's not using SQL Server transactions) So, for every record it works with, a copy is made out of the database, changes are made in memory, a delete of the database record is done, then the record is re-inserted.
With this kind of behavior in db A, I'm not sure what it would do to log-shipping or transactional replication. I do know that I want to minimize the changes required at the SQL CE instances to keep the sync operation to a minimal cost.
Any suggestions?
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Jul 25, 2015
I started to working on a project. I dont have a lot experiences except basic information. I just want to ask can I use symbols in primary key column like 2015/1234 etc. for file numbers. These are file numbers and must be unique so i decided to make them primary keys but im not sure that i can use symbols.
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Sep 3, 2015
We want to add a new int identity column as a primary key to an already existing table that has a primary key on Guid. Here is the DDL:
CREATE TABLE [dbo].[VRes](
[VResID] [uniqueidentifier] NOT NULL,
[Mes] [varchar](max) NOT NULL,
[PID] [uniqueidentifier] NOT NULL,
[Segt] [int] NOT NULL,
[code]....
Also we currently have 3 million rows on this table. Is having an integer column as identity column and primary key better or shd I consider using BigInt?
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Jul 14, 2015
I have a database around 500 GB. right now the database have only one data file and one log, it has only one filegroup also.all the indexes and table are placed in Primary Filegroup . we are going to separate them. the planing is to move all the indexes to Secondary filegroup and all the table will be in Primary filegroup.But there will be a problem while implementing it because there are around 600 tables and each table have at least 2 non-clustered index , so is there any way to move all the index to Secondary Filegroup.
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Nov 6, 2015
I have come up with one scenarios where I have three table like Product, Services and Subscription. I have to create one table say Bundle where I can have some of the product id , service id and Subscription id , i.e. a bundle may contains sum prduct , services and subscription . How I can design these relations ?
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Jun 13, 2015
I am designing a database. I want to define a automatic sequence on a table primary key field. what is the best solution for it?
I know I can enable identity property for a field, but it has some problems ( for example its seed jumps on restart and unsuccessful events)
I also can use some calculated sequences. for example I can calculate max of the filed values and after incrementing use it as key for new inserted record.
which one is better?
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May 13, 2015
I have a scenario like below
Product1
Product2 Product3
Product4 Product5
Product1 1
1 0 0
1
Product2 1
1 0 0
1
Product3 0
0 1 1
0
Product4 0
0 1 1
0
Product5 1
1 0 0
1
How to design tables in SQL Server for the above.
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Feb 13, 2002
Ok, I'm doing a football database for fixtures and stuff. The problem I am having is that in a fixture, there is both a home, and an away team. The tables as a result are something like this:
-------
Fixture
-------
fix_id
fix_date
fix_played
----
Team
----
tem_id
tem_name
-----------
TeamFixture
-----------
fix_id
tem_id
homeorawayteam
goals
It's not exactly like that, but you get the point. The question is, can I do a fixture query which results in one record per fixture, showing both teams details. The first in a hometeam field and the second in an away team field.
Fixture contains the details about the fixture like date and fixture id and has it been played
Team contains team info like team id, name, associated graphic
TeamFixture is the table which links the fixture to it's home and away team.
TeamFixture exists to prevent a many to many type relationship.
Make sense? Sorry if this turns out to be really easy, just can't get my head around it at the mo!
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Mar 9, 2014
I am developing asp.net application with sql server database
I have table FinancialYear
caseno(unique) finyear
1 2013-2014
2 2013-2014
3 2013-2014
1 2012-2013
2 2012-2013
3 2012-2013
For financial year-2013 to 2014. if i insert record ( select max(caseno) +1).
insert into finanancialYear values(max(caseno) +1,2013-2014)
if i delete record caseno:3 from the table,
select max(caseno)+1 will be 3
Which is already deleted and again that record with caseno 3 will be inserted
For every financial year in 'FinancialYear' table,.caseno will be reset to 1
And if I add new record in finyear 2012-1013
then max(caseno) will be last value of caseno of that financial year 2012-2013
Again insert becomes
insert into finanancialYear values(max(caseno) +1,2012-2013)
I have given the data.
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Aug 28, 2015
I desire to have a clustered index on a column other than the Primary Key. I have a few junction tables that I may want to alter, create table, or ...
I have practiced with an example table that is not really a junction table. It is just a table I decided to use for practice. When I execute the script, it seems to do everything I expect. For instance, there are not any constraints but there are indexes. The PK is the correct column.
CREATE TABLE [dbo].[tblNotificationMgr](
[NotificationMgrKey] [int] IDENTITY(1,1) NOT NULL,
[ContactKey] [int] NOT NULL,
[EventTypeEnum] [tinyint] NOT NULL,
[code]....
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Apr 17, 2014
Got the following error when the backup was run
Executing the query "BACKUP DATABASE [msdb] TO DISK = N'd:Sql backups..." failed with the following error: "Violation of PRIMARY KEY constraint 'PK__backupse__21F79AAB7WERB85D3'. Cannot insert duplicate key in object 'dbo.backupset'. The duplicate key value is (16771).Could not insert a backup or restore history/detail record in the msdb database. This may indicate a problem with the msdb database. The backup/restore operation was still successful.
12 percent processed.
21 percent processed.
31 percent processed.
41 percent processed.
[code]...
The statement has been terminated.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly.
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Apr 22, 2014
In what situations we can create primary key on a table? I mean what is the minimum no of rows we can prefer to create PK.
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Mar 9, 2015
We have H/A setup on SQL2012. Seems to work fine.I thought there was code I could add that would check to see if it was running on the primary node?
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Sep 23, 2015
"If we fail over a SQL AG group on a failover cluster from one node to another making the secondary the new primary, is there any reason why we would have to fail it back over to the old primary node?"
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Apr 29, 2014
Can we have blank value in Primary key field? Two fields are chosen as Primary Key for this table but the issue is at any given time one value will be blank when other is populated. Does sql server still order the records based on these keys? (Clustered index). Or should I just go about adding ID (identity)?
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Dec 15, 2014
What is the simple way to remember Primary and foreign key?
Why is the ID column in a table declared as a integer datatype?
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Mar 6, 2015
During the installation of the SSISDB in SQL 2012 AG, the password used to encrypt the database was not preserved. Now when the server is failed over, the SSISDB on the new primary node is not use-able.Document the password and decrypt after using the master key after failover.
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May 23, 2015
Can a Primary Key column also be a Identity column? The reason I am asking this question is because I have created a table and each time I insert data into the Address Table I am also inserting the AddressID, how do I get the Primary Key (AddressID column) to self generate ID values.
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Sep 5, 2015
I am migrating data. I found a strange thing in the existing table, there is a column named workshopCaseID in a TruancyCase table ,The datatype for workshopCaseID is an int (null). it is a FK, there are some records are 0 values, but the fk referenced primary table only have 1-8 values, how are the 0 values get inserted there?
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Mar 20, 2014
just i see a database and a table 'tbl_OutBox_MT' where there is now primary key and have index (non unique, non cluster). and it store almost 3000000 data per everyday. and wipe out data from their and archive all data to other location and broadcast this table 'tbl_OutBox_MT' by mobile operator everyday from morning to evening. but when it perform broadcast it to mobile operator it takes huge time. because this table gather data from different sources (tables) by using complex query and INSER INTO statement and insert into this table.
I need to perform first, my observation is there is no primary key. when i run any complex query into this table it takes huge time and sometimes shows transaction deadlock error.
CREATE TABLE [dbo].[tbl_OutBox_MT](
[TRAN_ID] [varchar](36) NOT NULL,
[OUT_MSG_ID] [int] IDENTITY(1,1) NOT NULL,
[OUT_MSG_ID_TELCO] AS (CONVERT([bigint],((((CONVERT([varchar](4),datepart(year,[PROCESS_TIME]),(0))+case len(CONVERT([varchar](2),datepart(month,[PROCESS_TIME]),(0))) when (1) then '0' else '' end)
[code]....
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Apr 11, 2014
Looking for info on ole/requirement of primary and secondary replica under SQL Server 2012 AlwaysOn.
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May 4, 2014
I've following query which display the result as required, but I need to get the missing Primary Key Values which are not available in the result:
SELECTA.SignedByUserID, B.FullName, COUNT(A.OutletID) AS TotalSignups, DATENAME(Month, A.SignupDate) AS Month
FROMdbo.tblMer_Outlet AS A LEFT OUTER JOIN dbo.tblGen_Users AS B ON A.SignedByUserID = B.UserID
WHERE(A.SignupDate >= '2014-04-01 00:00:00' AND A.SignupDate <= '2014-04-30 23:59:59')
GROUP BY A.SignedByUserID, B.FullName, DATENAME(Month, A.SignupDate)
This Query returns the following result:
SignedByUserID FullName TotalSignups Month
--------------------------------------------------------
9 Babu Raj 16 April
11 Faheem 19 April
39 Fasil Abbas 16 April
29 Hafiz Suleman 10 April
[code]....
which does not have a signup for the month of April, but I need it to be available for this or any upcoming month. I need this orr all users, which does not exists in the context needs to be displayed in the result.
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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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Sep 24, 2014
I've two tables A, B. In A table, I need to define the primary key with combination of 2 columns and this Primary Key will be a foreign key in table B. Based on these PK and FK I'll be writing a join to get the second column in table B.
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