Data Extraction

[deusalexmachina]

Sample set of values from columns / API (initial metadata)

Output: For each table, output the corresponding metadata for each column.

Write code to extract from each column:

1. Number of non-empty cells
2. Number of empty cells
3. Number of distinct values
4. Top-5 most frequent value(s)

Considerations:

• skewed data
• profiling runtime
• optimize as much as possible