Tagged Questions

3
votes
1answer
34 views

checksum(newid()) as primary key - what happens if a collision occurs?

Inspecting a rather critical database that is used by some software on my system, I found that one of the tables had a primary key on the column Id, where Id is calculated using checksum(newid()). ...
1
vote
1answer
41 views

Key lookup partition pruning

I have a query inner joining multiple tables all of which are partitioned and have 10 partitions each: SELECT A.COL1, B.COL2, C.COL3 FROM A INNER JOIN B ON A.ID = B.ID INNER JOIN C ON A.ID = C.ID ...
2
votes
1answer
60 views

Validate Primary Key and Index Selection

I have a table that will store transaction data from store sales registers, I have read quite a bit on index and key choice and below is what I have concluded is the best option but I am new to this ...
6
votes
3answers
136 views

Primary Key efficiency

If I need a table to hold Point of Sales transactions, and am told I need to store: Country ID Store Number POS Terminal Number Transaction Date Item Code Teller ID Another Field More Fields Now, ...
11
votes
4answers
288 views

Best solution to fixing database design with GUID as primary key

I am after some confirmation of this idea to fix a badly performing database or a better suggestion if any one has one. Always open to better suggestions. I have a very large database (20+ million ...
3
votes
4answers
166 views

PRIMARY KEY CONSTRAINT fundamentals

Can you explain why "primary key constraint" exists if, as you know, it is possible to create relationships between tables using unique indexes only ? The RDBMS that is used is SQL Server. In fact, ...
2
votes
1answer
156 views

SQL Server - storing ulong as primary key

I need to store ulong values as a primary key in SQL Server. Since SQL Server doesn't have a ulong datatype (or for that matter anything unsigned), the only way to go is to have column as ...
3
votes
1answer
126 views

Index Key Column Order

I have created a joining table for many-to-many relationship. The table only has 2 cols in it, ticketid and groupid typical data would be groupid ticketid 20 56 20 87 20 ...
12
votes
5answers
380 views

Sequential GUID or bigint for 'huge' database table PK

I know this type of question comes up a lot, but I've yet to read any compelling arguments to help me make this decision. Please bear with me! I have a huge database - it grows by about 10,000,000 ...
1
vote
1answer
158 views

How to alter primary key constraint for 2 columns in same table in SQL Server?

In SQL Server, I already created a table called tblDatabase with some columns. I want to add a primary key on the two columns DatabaseName and Servername. I tried to add: ALTER TABLE tblDatabase ...
2
votes
2answers
239 views

Replacing composite key with surrogate

I have the following table that has a couple of million rows in it and is 99% fragmented virtually all of the time. My plan was to insert a IDENTITY field as a surrogate key to replace the current ...
2
votes
0answers
127 views

How can I manage Primary Key length limit of 900 bytes when using hirarchyid 2 columns?

I have to define a Primary key on a table which has following 4 columns and its data types. GSiteID hirarchyid,, SiteID varchar(10), GComID hirarchyid, ComID nvarchar(10) As we know there is limit ...
1
vote
2answers
128 views

How do I create a rule for a Primary Key

I am using SQL Server 2005 and I need to create a primary key with an alpha character and 3 numbers together: p001 b201 I know I need to create a rule and bind that rule to the primary ...
3
votes
0answers
205 views

Why are runtimes different for a table including a primary key versus a table with a clustered unique index added after population

When I create a temporary table with a PK defined from the outset like this I get great performance in subsequent joins on that key: create table #temp ( field1 int not null field2 int ...
4
votes
1answer
311 views

How does SQL Server choose an index key for a foreign key reference?

I am working with a legacy database that was imported from MS Access. There are about twenty tables with non-clustered, unique primary keys that were created during the MS Access > SQL Server upgrade. ...
9
votes
4answers
755 views

Sort order specified in primary key, yet sorting is executed on SELECT

I'm storing sensor data in a table SensorValues. The table and primary key is as follows: CREATE TABLE [dbo].[SensorValues]( [DeviceId] [int] NOT NULL, [SensorId] [int] NOT NULL, [SensorValue] ...
1
vote
1answer
332 views

SQL - double column used from primary key with autoincrement

I am user the following as primary key in the SqlDB: I am doing the Index as Autoincrement, but it is autoincremented in general not per user. Example userid=1,index=1, then insert another for ...
2
votes
2answers
2k views

Single Identity column and composite key, which to make primary?

I've got a table that's a working copy subset of a base table. The base table has a composite key with a clustered index. However I need a single column unique identifier for my framework to work ...
3
votes
3answers
2k views

SQL table design for primary keys (best practice)

I have a User table that contains the following fields ID (Auto-generated GUID) UserName Password FirstName LastName Email AddressID (GUID) This is linked to the table Address (1-1 relation) which ...
20
votes
7answers
2k views

Why should I create an ID column when I can use others as key fields? [duplicate]

Possible Duplicate: Why use an int as a lookup table's primary key? So far, I'm accustomed to creating an ID column for every table and it is practical in a way that it makes me not ...
22
votes
4answers
7k views

When should a primary key be declared non-clustered?

While creating a test database for another question I asked earlier, I remembered about a Primary Key being able to be declared NONCLUSTERED When would you use a NONCLUSTERED primary key over a ...
1
vote
2answers
476 views

How can an identity primary key index become fragmented?

From what I understand about index fragmentation, this should not be possible. The cases I have found in my databases are non-clustered. Example: ALTER TABLE [dbo].[ClaimLineInstitutional] ADD ...
2
votes
2answers
307 views

What are the pros and cons of using my customer codes as a primary key?

I am designing a database for one of my sales teams. Right now, the goal is to get a master list of customers and their mailing addresses, but the DB will eventually expand to track some other ...
1
vote
1answer
107 views

Is it require to fill all tables inside of the database?

Now,I created upper that table and in order to test I will give 3 textboxes values as below. SqlCommand cmd = new SqlCommand ("Insert Into dbo.PrnInf(PrnName, PrnSurName, PrnEgn ) Values ...
12
votes
5answers
2k views

Why use an int as a lookup table's primary key?

I want to know why I should use an int as a lookup table's primary key instead of just using the lookup value as the primary key (which in most cases would be a string). I understand that using a ...
32
votes
3answers
5k views

Guid vs INT - Which is better as a primary key?

I've being reading around reasons to use or not Guid and int. int is smaller, faster, easy to remember, keeps a chronological sequence. And as for Guid, the only advantage I found is that it is ...