Sorry for the ignorant question, but what kind of applications wouldn't require an ACID compliant database server? I have a SQL Server background where ACID has always "been there", and now researc...

I'm just trying to get a general idea of what views are used for in RDBMSes. That is to say, I know what a view is and how to make one. I also know what I've used them for in the past. But I want t...

You often see database fields set to have a magnitude of 255 characters, what is the traditional / historic reason why? I assume it's something to do with paging / memory limits, and performance bu...

I am working on an online survey. Most questions have a scale of 1-5 for an answer. If we need to add a question to the survey, I use a simple web form, which does an INSERT into the appropriate ta...

Just found out that Oracle does not like it when you use the AS keyword to alias a subquery: SELECT * FROM (SELECT * FROM products) AS p I need to keep my SQL queries as portable as possible. Wi...

In SQL Server 2005 I just struck the infamous error message: Introducing FOREIGN KEY constraint XXX on table YYY may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UP...

I am migrating data from one database schema to another. The old schema has a categorization system based on an adjacency list, with id, category, and parent_id. If one category is under a second, ...

Can we get a list of basic optimization techniques going (anything from modeling to querying, creating indexes, views to query optimization). It would be nice to have a list of these, one technique...

I often see people who write SQL like this: SELECT * from TableA LEFT OUTER JOIN TableB ON (ID1=I2) I myself write simply: SELECT * from TableA LEFT JOIN TableB ON (ID1=I2) To me the "OUTER" ...

My company has me working on finishing a back end for Oracle for a Python ORM. I'm amazed at how much differently RDBMSes do things even for the simple stuff. I've learned a lot about the differenc...

I recently sped up a complicated query by an order of magnitude by giving SQLite a good index to work with. Results like this make me wonder if I should index a lot of other fields that are commonl...