Develop a schema

Vertica provides two general approaches to developing a table definition during data exploration without resorting to inspecting data files by hand: inference and flex tables.

If your data is in Parquet, ORC, JSON, or Avro format, you can use a Vertica function to inspect a sample file and automatically generate a "first draft" of a table definition. The output indicates where the function could not make a decision, so that you can focus on those areas as you refine the definition. Using this approach, you iteratively test sample data, refine the table definition, and test more data until you arrive at a satisfactory table definition.

Alternatively, you can use flex tables, a special type of table designed for exploring data with an unknown or varying schema. You can use flex functions to explore this data and materialize individual columns in your table. When you have identified the columns that should consistently be part of your table, you can then define a regular (non-flex) table.