Here’s the announcement – and Microsoft SQL Server Developer Edition is now free! Is it big news? Yes, but if you’re a developer the question of whether to favour an upgrade in due course is more nuanced than it used to be. Continue reading
Case sensitivity in Sql Server depends on the collation applicable to the column, which of course is often the same as the database default collation. Unlike Oracle, Sql Server out of the box is case-insensitive (at least in English-speaking Western countries).
This means that you don’t need to consider whether data is upper- or lower-case when you’re searching for it, which tends to make an application more robust. You probably won’t want to change that. On the other hand, if your database stores codes or descriptions used as query filters (not including proper nouns like personal names where the capitalisation is part of the data) there may be an advantage to standardising on upper or lower case. You’ve reduced the need to take account of upper/lower case in client code, where string comparisons may be case-sensitive.
Is there an easy way? Yes. Continue reading
The JSON has landed (in beta at least) – and I think it’s now some practical use. I’ve collected a few technical references here. There may not be a native JSON type yet, but there are workarounds to provide the kind of assurance control-freak RDBMS developers find comforting. I’ve shown some of them in the code sample below. Continue reading
Some hand-matching of internal/external records may be needed even in an automated reconciliation. The matches will be stored in a database. Rules on matching can be enforced in the application, but there are often good reasons to place them in the database. In Sql Server, a filtered index (with a WHERE clause, in this case excluding Nulls) on the table can make this easier and more correct. Continue reading
Indexes often double as constraints. Each combination of values must only appear once among the columns of an index defined as UNIQUE. The “filtered” index allows some refinement. Suppose that in one column you won’t allow a specific value to appear more than once, but you don’t mind other values being duplicated.
A good example would be the IS_LATEST_VERSION column in a data warehouse table. Continue reading
Well, not literally – these are features I tend to overlook because I don’t often need them. If you’re the same, this may be helpful. It isn’t a complete list (I’ve forgotten the others) but I’ll try to add to it as things come to mind. Continue reading
Someone accidentally found my Sql Collation Cheat Sheet while searching for a “Sql JOIN Cheat Sheet” so I thought I’d knock out a post on the topic. Towards the end, you’ll find a script that demonstrates them. The script was run in Azure Sql. Some joins may be Microsoft extensions to the ANSI standard. Look at the documentation for fuller information.
When I was a beginner I had thought there was a deep meaning to the words “left” and “right”, as in LEFT OUTER JOIN. It was a mild let-down to find out that it only refers to placement of the table name in relation to the “JOIN” keyword; switching a LEFT OUTER to a RIGHT OUTER join defines the table named after the join keyword as the outer table. Continue reading