The Video
The
find() function for the MySQL Document Store is a very powerful tool and I have just finished a handy introductory video. By the way -- please let me have feed back on the pace, the background music, the CGI special effects (
kidding!), and the amount of the content.
The Script
For those who want to follow along with the videos, the core examples are below. The first step is to connect to a MySQL server to talk to the
world_x schema (Instructions on loading that schema at the first link above).
\connect root@localhost/world_x
db is an object to points to the
world_x schema. To find the records in the
countryinfo collection, use
db.countryinfo.find(). But that returns 237 JSON documents, too many! So lets cut it down to one record by qualifying that we only want the record where the
_id is equal to
USA,
db.countryinfo.find(‘_id = “USA”’)
Deeper Level items in the Document
You can reach deeper level items by providing the path to the object such as
db.countryinfo.find(‘geography.Continent = “North America”). Be sure to remember Case Sensitivity!!
Limits, Offsets, and Specifications
It is very simple to place restrictions on the amount of output by post pending
.limit(5).skip(6). And you can specify which parameters meet you specification by using
find(‘GNP > 8000000’)
Limiting Fields
But what if you do not want all the document but just a few certain fields. Then post pend
.fields([“Name”, “GNP”]) to
find(). And once again you can dig deeper into the document with specifying the path, such as
.fields([“Name”, “GNP”, “geography.Continent”]).sort(“GNP”).
Sorting
Yes, you can easily sort the output from find() by adding
.sort(“GNP”,”Name”) at the end.
More Complex Searches
Of course you can make the
find() function perform more complex dives into the data such as
db.countryinfo.find(‘GNP> 500000 and IndepYear > 1500”).
Parameter Passed Values
And find of parameter passed values will be happy to find they have not been forgotten.
db.countryinfo.find(“Name = :country”).bind(“Country”,”Canada”)
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