join

2 Results

Dictionary

join

In relational database management, to match one table (file) against another based on some condition creating a third table with data from the matching tables. For example, a customer table can...

Dictionary

Definition: join

In relational database management, to match one table (file) against another based on some condition creating a third table with data from the matching tables. For example, a customer table can be joined with an order table creating a table for all customers who purchased a particular product.

The default type of join is known as an "inner" join. It produces a resulting record if there is a matching condition. For example, matching shipments with receipts would produce only those shipments that have been received. On the other hand, an "outer" join using that example would create a record for every shipment whether or not it was received. The data for received items would be attached to the shipments, and empty, or null, fields would be attached to shipments without receipts.


join

A Simple Join
This example matches the sales table against the product table based on product number to derive the product description.





Sponsored White Papers, Webcasts & Resources

  • Apple snags ex-OLPC security chief

    Former director of security architecture at One Laptop per Child (OLPC) Ivan Krstic has joined Apple to help thwart hacker attacks against the Mac operating system. Krstic, a...

    Blog posts | May 13, 2009 10:33am PDT

  • Beyond findability: The search for active intelligence

    It took a decade of indexing advances such as skip lists and index compression to make indexing practical, and another decade of computing advances to give us billions of searchable documents says...

    News items | October 31, 2008 8:01am PDT

Additional Results

ie8 fix

The best of ZDNet, delivered

ZDNet Newsletters

Get the best of ZDNet delivered straight to your inbox

Facebook Activity

ie8 fix