Tagged Questions

2
votes
2answers
53 views

Constraints based on other columns

Is it possible to limit what values are allowed in a coulumn based off of other values in the row? For example, my table: ID Test_mode Active -- --------- ------ 1 1 Null 2 0 ...
1
vote
1answer
81 views

SQL Azure: Drop Constraint and Index

This may be a stupid question, but I'm not a DBA and just wanna make sure of what I'm doing before I make a mistake. Here is my question: When dropping Constraints, are their indexes dropped as well? ...
1
vote
2answers
122 views

Only one NULL for one part of primary key

I have two date columns : "start date" and "finish date". I want to make sure that there can be only one null value in the "finish date" column (which should be current state if it's NULL) for one ...
3
votes
1answer
116 views

I need help using hierarchyid datatype and requiring a unique constraint on a varchar field

I want to resolve a bunch of tables that had parent->child->grandchild relationships into a single table using hierarchyid identifiers. Here is what I came up with based on what I had. CREATE ...
3
votes
1answer
116 views

Restrict record to be update or deleted according to dates inside row for SQL Server 2005

I have transaction replication between two SQL Servers. For testing purposes I deleted a lot of records at the subscriber that still existed at the publisher. I now know that if someone updates, ...
3
votes
3answers
1k views

Altering nullability of column in SQL Server

Say I have the following table: CREATE TABLE test(test_id int not null identity primary key, field1 int not null, field2 int ); CREATE INDEX IDX_test_field1 ON test(field1); CREATE INDEX ...
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 ...
2
votes
3answers
204 views

SQL Server : explicitly create an index on a primary key and unique fields

UPDATED: I'll make the question clearer as the first answer isn't quite what I was looking for. How can I execute this create table statement and ensure that the two automatically created indexes ...
5
votes
2answers
126 views

Unique Contraint/Index Based On Values

I have a table that has the following column definitions: ID (INT, PK) Name (VarChar) Active (Bit) Bunch_of (Other_columns) Question: I want to have a Constraint on Name/Active such that we can ...
3
votes
2answers
3k views

What to use, CASCADE DELETE rule or ON DELETE trigger for one to many constraint?

I would like to ask about how to handle this relationship. For better view I've tried to simplify and convert my situation into how I think StackOverflow question voting has (sorry if not :-) I ...
3
votes
2answers
776 views

Having a unique ID for 2 different tables

We would like to use two different tables, one will hold an object when it is 'Active', and the other will hold the object once it becomes'Non-Active'. The ID is therefore unique per both tables ...
4
votes
1answer
1k views

How do you create a relationship to a non-primary key in SQL Server?

I have a Users table which has two columns a primary key called UserID and another column called UserName. UserID (int) PK UserName (varchar(256) They are both unique but I decided for reasons to ...
2
votes
2answers
463 views

Temporarily disable checking of constraints

I'm bulk inserting rows into a database and I'm finding (through the query analyser) that the foreign key constraints are taking about 20% of the insertion time. I've tried creating a separate index ...
3
votes
1answer
1k views

How to write a check constraint to disallow empty varchar fields?

On SQL Server not nullable varchar columns can hold empty strings. Under ORACLE they can't, because varchar2 treat '' as equivalent to NULL. If you design a database schema suitable for both RDBMS ...
1
vote
2answers
667 views

SQL Server 2008 R2 - How to check Foreign Key constraints in a transaction only when committed?

We are synchronizing tables between two databases (yes, it needs to be done by our software and not by replication etc.) Both databases are identical with many foreign-key constraints on tables. ...
4
votes
6answers
903 views

Any way around unique index 16 column max

According to the CREATE INDEX documentation: Up to 16 columns can be combined into a single composite index key. We've got a table with ~18 columns that need to form a unique combination. This ...
5
votes
2answers
2k views

Check constraint only one of three columns is non-null

I have a (SQL Server) table that contains 3 types of results: FLOAT, NVARCHAR(30), or DATETIME (3 separate columns). I want to ensure that for any given row, only one column has a result and the other ...
2
votes
1answer
452 views

Trusted Constraints and NOT FOR REPLICATION

Version and Build: SQL Server 2005 SP4 (9.0.5000) As a disclaimer of sorts, I am asking this question to generate some discussion and/or debate on the topic. I don't know if there is really a ...
4
votes
2answers
364 views

How to mark an item as “Expired” when it's ExpiryDate value is in the past?

I have a table of items, each of which has a Status and ExpiryDate. What is the best way of enforcing this: when ExpireyDate > DateTime.Now update Status to "expired" I could have a stored ...
6
votes
3answers
1k views

Dropping a constraint (index) on a column

How can I modify the type on a table that has an index on it? I tried to do an alter column on an empty table to modify the type from date time to varchar(15) and got errors saying that it had ...
8
votes
2answers
2k views

Unique Constraints on Nullable Columns in SQL Server 2005

In this one project I am working on, I need to set a particular field to be unique (not a problem!) but if the field is null I want the constraint to be ignored. In Sql Server 2008 I use filtered ...
16
votes
3answers
4k views

When should I use a unique constraint instead of a unique index?

When I want a column to have distinct values, I can either use a constraint create table t1( id int primary key, code varchar(10) unique NULL ); go or I can use a unique index create table t2( id ...
5
votes
2answers
476 views

Dropping duplicate|redundant Unique Constraint from FILESTREAM table

I have a table with a FILESTREAM column, and it has two unique constraints specified for the same FILESTREAM column, ie: ALTER TABLE [dbo].[TableName] ADD CONSTRAINT ...