CODEWITHSUNDEEP
google-cloud-platformgoogle-bigquery
KMI
KMI

Reputation: 21

Is there a way to clear multiple tables at once?

I want to clear the tables stored in a specific dataset of bigquery.

In the console screen, you cannot delete multiple tables at once.

It was also not possible to delete using the * in the bq CLI.

Is there a way to clear multiple tables at once?

Upvotes: 0

Views: 406

Answers (2)

Alexandre Moraes
Alexandre Moraes

Reputation: 4042

While in the documentation it is stated that you can delete only one table at a time, it is possible to make an API request with a Python script in order to delete all the tables inside a dataset.

I created and tested the following script:

from google.cloud import bigquery

#construct BigQuery client object
client = bigquery.Client()

#select your dataset and list the tables within it 
dataset_id='project_id.dataset'
tables = client.list_tables(dataset_id)  

#inititalizing the list of tables
list_tables=[]
    
for table in tables:
    #Create a list with the able reference for deletion 'project.dataset_id.table_id'
    id =".".join([table.project,table.dataset_id,table.table_id])
    list_tables.append(id)
    
    #List of tables
    print(list_tables)

#Delete all the tables inside the list of tables     
for table in list_tables:
    #print(table)
    client.delete_table(table)
    
print("{} {}".format("Number of deleted tables in the dataset:", len(list_tables)))

I executed the above code using Jupyter Notebook with Python 3. If you run it in your cloud shell environment, make sure you install all the dependencies pip install --upgrade google-cloud-bigquery.

Upvotes: 1

SANN3
SANN3

Reputation: 10069

I had similar situation and used the following Java code to delete the large no of tables.

Replace dataset and table_prefix values.

Set the service account JSON key file path as GOOGLE_APPLICATION_CREDENTIALS environment variable.

Code:

import java.util.ArrayList;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;

public class TableKiller {
    String dataset = "MY_DATASET";
    String table_prefix = "temp_table_";

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        new TableKiller().deleteAll();
    }

    public void deleteAll() throws InterruptedException, ExecutionException {
        ArrayList<String> tableNames = new ArrayList<>();
        BigQuery bigQuery = BigQueryOptions.getDefaultInstance().getService();
        int i = 1;

        bigQuery.listTables(dataset, BigQuery.TableListOption.pageSize(1000))
                .iterateAll()
                .forEach(table -> {
                    String tableName = table.getTableId().getTable();
                    if (tableName.startsWith(table_prefix)) {
                        tableNames.add(tableName);
                        System.out.println("Added " + tableName + i);
                    }
                });

        ForkJoinPool forkJoinPool = new ForkJoinPool(200);
        forkJoinPool.submit(() -> tableNames
                .parallelStream()
                .forEach(this::deleteTable)).get();

    }

    private void deleteTable(String tableName) {
        BigQuery bigQuery = BigQueryOptions.getDefaultInstance().getService();
        bigQuery.delete(TableId.of(dataset, tableName));
        System.out.println("Deleted " + tableName);
    }
}

Upvotes: 0

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