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17.2. Tables of Records

Say you are conducting research about bike sharing for an internship in Washington D.C. You are given the Capital Bike Sharing dataset, contains information on Washington D.C.’s bike share program for 2011. The database has hundreds of thousands of records about every ride that anyone took and you would like to look for patterns in the data to understand questions like: “How long is the average ride?” and “Where is the most popular place to start a ride?”

In a database, the data is arranged in tables like the one shown below. This trip_data table has all of the information about individual trips that were made. Each row in a table is a record - here, each record is an individual trip someone made.

The columns are the pieces of data associated with each record. Here is a description of the columns available in the trip_data:

Column Name	Description
index	A unique number that identifies the trip
duration	The time in seconds of the trip
start_date	Date and time the bike was checked out
end_date	Date and time the bike was returned
start_station	Station number the bike was checked out at
end_station	Station number the bike was returned at
bike_number	Which bike was used
member_type	Type of user - Casual (one time), or Member

Note

Don’t worry about memorizing all of the columns, you can check back here as needed.

Information about the stations is stored in a separate table called the bikeshare_stations table. In that table, each record is the information about one particular station.

It has these columns:

Column Name	Description
index	A number that identifies the record (1, 2, 3…)
station_id	A unique number that identifies the station
name	The name of the station
status	If the station is open or closed
latitude	Latitude (North-South position) of station
longitude	Longitude (East-West position) of station

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