In PostgreSQL, a partial index is an index that’s built on a subset of the rows in a table. It includes only the rows that satisfy a given condition specified with the WHERE clause.
Partial indexes can help us achieve faster queries, reduced storage, and lower overhead for write-heavy workloads.
Below is a quick example that demonstrates how to create a partial index in PostgreSQL.
Continue readingThe INCLUDE option in SQL Server allows us to include non-key columns in a nonclustered index. These columns are not part of the index key (which SQL Server uses to order and search the index), but they are stored with the index pages.
The INCLUDE option can significantly improve query performance when additional columns are needed by a query but are not part of the index key.
Dropping a primary key in any RDBMS is a critical operation that requires careful consideration, especially when there are related foreign keys in other tables.
The decision to drop a primary key is not to be taken lightly.
That said, this article walks through the process of how to drop a primary key in SQL Server, while highlighting important considerations.
Continue readingBy default, SQL Server creates indexes automatically when we do things like create certain constraints. We also have the option of creating indexes separately for our own (usually performance related) reasons. Either way, there may be times where we need to check what indexes we have in our database.
In this article, we’ll explore four ways to retrieve information about all indexes in a SQL Server database.
Continue readingIf you’re getting SQL Server error 1909 that reads something like “Cannot use duplicate column names in index. Column name ‘FirstName’ listed more than once“, it appears that you’re trying to create an index, but you’re listing the same column multiple times.
Each column can only be listed once in the index definition.
To fix this issue, make sure each column is listed only once.
Continue readingIn PostgreSQL, both UNIQUE indexes and UNIQUE constraints can be used to enforce uniqueness on columns.
So you may be wondering; if that’s true, why have both? And are there any circumstances that we should choose one over the other?
Let’s find out.
Continue readingFillfactor is an option that allows us to fine tune index data storage and performance in SQL Server. It determines the percentage of space on each leaf-level page to be filled with data, therefore reserving the remainder on each page as free space for future growth.
The default fillfactor can be set as a configuration option. SQL Server sets this value to 0, and so this is what’s used when we create an index without specifying a fillfactor. However, it’s possible to change this value, and so at some stage we might want to check to see what the current value is.
Below are two ways to check the fill factor configuration option.
Disabling an index in SQL Server can be a useful technique to improve the performance of bulk insert operations or when you need to perform maintenance on your database.
This article provides the code/syntax required to disable an index in SQL Server.
Continue readingIn PostgreSQL, indexes on expressions (also known as “functional indexes”) allow you to create an index not just on a column but on the result of an expression or function applied to a column (or multiple columns). This can significantly improve query performance when the same expression is used frequently in queries, especially for complex calculations or transformations.
Continue readingIf you’re getting an error that reads something like “Cannot create index on view ‘MyView’ because the view is not schema bound” in SQL Server, it sounds like you’re trying to create an index on a view that’s not schema bound.
Indexes can only be created on schema bound views.
To fix this issue, define the view as schema bound before creating the index.
Continue reading