I’ve shown you how to create indexes, CLUSTERED versus NONCLUSTERED indexes, today I want to build on that. Let’s say you have a lookup query that takes names, and returns an ID for that name, you can actually build your query in a way where it would look up that data using just an index. …
Tag: DEV
SQL 102 – UNIQUE INDEX
Ok, you understand how to create an INDEX. You understand the differences in CLUSTERED and NONCLUSTERED indexes. Did you know you could index a view? You can. But before you start adding indexes, just like you would for a table, you’ll have to create an UNIQUE CLUSTERED INDEX on that index. The reason for that…
SQL 102 – CLUSTERED vs. NONCLUSTERED Indexes
Previously, I covered the basics of creating an index using CREATE INDEX. Today, I’m going to dig a little deeper. I’d like to teach you the difference in an CLUSTERED versus a NONCLUSTERED index. If you learn nothing else, know that a CLUSTERED INDEX physically orders the table, a NONCLUSTERED INDEX creates another “table” and…
SQL 301 – Views
At this point I’m sure you know how to CREATE and ALTER a VIEW. But today I’d like to go into a little more detail on views. I’d like to cover updatable views, and some additional options you can add to your CREATE or ALTER VIEW statements. Updatable Views You can write insert s, updates,…
Correlated Subqueries with Comparison Operators
If you haven’t used a sub query yet, I’m surprised. They can be incredibly useful. They can also be a crutch…but like I say time and again, each tool has it’s use. I’d like to go into a little detail on sub queries today by talking about correlated sub queries. Let’s say you wanted to…
Insert Triggers
An insert trigger is a Data Manipulation Language (DML) trigger that acts when a new record is added to the table. CREATE TRIGGER t_tableName_insert ON tableName AFTER|FOR|INSTEAD OF INSERT AS Some bit of T-SQ OK, let’s walk through this. CREATE TRIGGER begins the command. The next part t_tableName_insert is the trigger’s name. I follow a…
sql server 2000 + How to display date time
Over on Experts Exchange I saw a question that I get all the time, “How do I format this DATETIME like x?” If they’re asking to learn, I point them over to the CAST and CONVERT article on msdn. If you wish to change a Microsoft SQL DATETIME column from the standard format 2008-01-28 12:43:13.210…
SQL Session – Migrating From DTS to SSIS
If you’re not already a member of the Charlotte SQL Server User Group, go now and sign up. This group is a great resource of knowledge and connections to the SQL Server community in Charlotte, NC. Their plan is to get together once a month and discuss a new and interesting topic on SQL Server….
Triggers
Triggers are one of the most misunderstood features in Microsoft SQL server. Most of that misunderstanding comes from people implementing triggers with little understanding to their impact. Even worse, they’ll implement them without testing. And the worst of all, not using them, when the functionality being requested is the very definition of what a trigger…
SQL Session – What’s new in Katmai (SQL Server 2008)
If you’re not already a member of the Charlotte SQL Server User Group, go now and sign up. This group is a great resource of knowledge and connections to the SQL Server community in Charlotte, NC. Their plan is to get together once a month and discuss a new and interesting topic on SQL Server….