writeDisposition

Optional Specifies the action that occurs if the destination table already exists. The following values are supported: WRITE_TRUNCATE: If the table already exists, BigQuery overwrites the table data and uses the schema from the query result. WRITE_APPEND: If the table already exists, BigQuery appends the data to the table. WRITE_EMPTY: If the table already exists and contains data, a 'duplicate' error is returned in the job result. The default value is WRITE_EMPTY. Each action is atomic and only occurs if BigQuery is able to complete the job successfully. Creation, truncation and append actions occur as one atomic update upon job completion.