I'm using BigQuery both to store data within "native" BigQuery tables and to query data stored in Google Cloud Storage. According to the documentation, it is possible to query external sources using two types of tables: permanent and temporary external tables.
Consider the following scenario: every day some parquet files are written in GCS, and with a certain frequency I want to do a JOIN between the data stored in a BigQuery table and the data stored in parquet files. If I create a permanent external table, and then I update the files below, is the content of the table automatically updated as well, or do I have to recreate it from the new files?
What are the best practices for such a scenario?
Update BigQuery permanent external tables
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1 Answers
You don't have to re-create the external table again when you add new files into cloud storage bucket. The only exception is, if the number of columns is different in new file then the external table will not work as expected.
You need to use wildcard symbol to read files that matches to a specific pattern rather than providing a static file name. Example:
"gs://bucketName/*.csv"
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