Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

Although tables in SQL databases typically contain massive amounts of data, they’re not always in a format that can be used by data analysts. The data records in these tables need to be filtered ...

Unlock the full InfoQ experience by logging in! Stay updated with your favorite authors and topics, engage with content, and download exclusive resources. Agent workflows make transport a first-order ...

Multiple Detail Records - 4 in this case. (linked to the header record) Multiple Inventory Records - again, 4 - (each detail record points to one specific inventory record, but the inventory may be ...

I've said it before and I'll say it again: If you want to speed up your application, don't look at your code, look at your data access. The two slowest things you can do in application development are ...

A common SQL habit is to use SELECT * on a query, because it’s tedious to list all the columns you need. Plus, sometimes those columns may change over time, so why not just do things the easy way? But ...

In the original proposal for the World Wide Web, Tim Berners-Lee wrote: A generic tool could perhaps be made to allow any database which uses a commercial DBMS to be displayed as a hypertext view. We ...

The indexes on a the tables of a large database make a huge difference in its performance and utility. Without an index, locating a single record in a large table can take several seconds; with the ...