I wanted to get some data off an agent listing website and into a spreadsheet. I’d been meaning to play around with python for web scraping and this was the perfect excuse: There were just enough results that it would take longer to manually copy and paste them than to write a little python program. (I never want to automate something that will take less time to do than to automate, as long as I’m only going to do it once or twice…)
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Tag: hierarchical data
Recursive WITH, part III: IS_LEAF
The CONNECT BY syntax provides a useful pseudocolumn, CONNECT_BY_ISLEAF, which identifes leaf nodes in the data: it’s 1 when a row has no further children, 0 otherwise. In this post, I’ll look at emulating this pseudocolumn using recursive WITH.
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Recursive WITH, part II: Hierarchical queries
In my last post, I looked at using recursive WITH to implement simple recursive algorithms in SQL. One very common use of recursion is to traverse hierarchical data. I recently wrote a series of posts on hierarchical data, using Oracle’s CONNECT BY syntax and a fun example. In this post, I’ll be revisiting the same data using recursive WITH.
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CONNECT BY, Part II
In my last post, I used CONNECT BY to query a table holding the bones of the skeleton in the “Dem Dry Bones” song: since the skeleton in the song has a head with no parent bone (making it a root node), and each bone has only one parent bone, it’s hierarchical data.
In this post, I’m going to add an arm and some ribs to the skeleton to make the data more interesting to query.
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CONNECT BY, Part I
In my last post, I briefly covered what hierarchical data is and how it’s represented in an RDBMS using the adjacency list model. In this post, we’ll look at querying hierarchical data with Oracle SQL’s CONNECT BY construct, using a really fun example.
Hierarchical Data
This is the first in a series of posts about Oracle SQL and hierarchical data.