Data Catalog and crawlers

This page was generated from content adapted from the AWS Developer Guide

AWS Glue databases

• Note When you delete a database from the AWS Glue Data Catalog, all the tables in the database are also deleted.

Adding classifiers to a crawler

• Note If your data format is recognized by one of the built-in classifiers, you don't need to create a custom classifier.

• Note If the built-in CSV classifier does not create your AWS Glue table as you want, you might be able to use one of the following alternatives: Change the column names in the Data Catalog, set the SchemaChangePolicy to LOG, and set the partition output configuration to InheritFromTable for future crawler runs. Create a custom grok classifier to parse the data and assign the columns that you want. The built-in CSV classifier creates tables referencing the LazySimpleSerDe as the serialization library, which is a good choice for type inference. However, if the CSV data contains quoted strings, edit the table definition and change the SerDe library to OpenCSVSerDe. Adjust any inferred types to STRING, set the SchemaChangePolicy to LOG, and set the partitions output configuration to InheritFromTable for future crawler runs. For more information about SerDe libraries, see SerDe Reference in the Amazon Athena User Guide.