Check dataset existence
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A function to check whether a dataset exists.
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For detailed documentation that includes this code sample, see the following:
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[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],[],[[["\u003cp\u003eThis content provides code samples in Java and Python for checking if a dataset exists in BigQuery.\u003c/p\u003e\n"],["\u003cp\u003eThe Java code sample uses the \u003ccode\u003eBigQuery\u003c/code\u003e client library to check for a dataset's existence by name and returns whether it was found or not.\u003c/p\u003e\n"],["\u003cp\u003eThe Python code sample uses the \u003ccode\u003ebigquery\u003c/code\u003e library and handles the \u003ccode\u003eNotFound\u003c/code\u003e exception to determine whether a specified dataset is present.\u003c/p\u003e\n"],["\u003cp\u003eBoth code samples direct the user to authentication documentation to ensure proper setup using Application Default Credentials.\u003c/p\u003e\n"],["\u003cp\u003eBoth code samples are based on user defined parameters that need to be correctly setup before running.\u003c/p\u003e\n"]]],[],null,["# Check dataset existence\n\nA function to check whether a dataset exists.\n\nExplore further\n---------------\n\n\nFor detailed documentation that includes this code sample, see the following:\n\n- [Listing datasets](/bigquery/docs/listing-datasets)\n\nCode sample\n-----------\n\n### Java\n\n\nBefore trying this sample, follow the Java setup instructions in the\n[BigQuery quickstart using\nclient libraries](/bigquery/docs/quickstarts/quickstart-client-libraries).\n\n\nFor more information, see the\n[BigQuery Java API\nreference documentation](/java/docs/reference/google-cloud-bigquery/latest/overview).\n\n\nTo authenticate to BigQuery, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for client libraries](/bigquery/docs/authentication#client-libs).\n\n import com.google.cloud.bigquery.https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html;\n import com.google.cloud.bigquery.https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryException.html;\n import com.google.cloud.bigquery.https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryOptions.html;\n import com.google.cloud.bigquery.https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.Dataset.html;\n import com.google.cloud.bigquery.https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.DatasetId.html;\n\n // Sample to check dataset exist\n public class DatasetExists {\n\n public static void main(String[] args) {\n // TODO(developer): Replace these variables before running the sample.\n String datasetName = \"MY_DATASET_NAME\";\n datasetExists(datasetName);\n }\n\n public static void datasetExists(String datasetName) {\n try {\n // Initialize client that will be used to send requests. This client only needs to be created\n // once, and can be reused for multiple requests.\n https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html bigquery = https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryOptions.html.getDefaultInstance().getService();\n\n https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.Dataset.html dataset = bigquery.https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html#com_google_cloud_bigquery_BigQuery_getDataset_com_google_cloud_bigquery_DatasetId_com_google_cloud_bigquery_BigQuery_DatasetOption____(DatasetId.of(datasetName));\n if (dataset != null) {\n System.out.println(\"Dataset already exists.\");\n } else {\n System.out.println(\"Dataset not found.\");\n }\n } catch (https://cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryException.html e) {\n System.out.println(\"Something went wrong. \\n\" + e.toString());\n }\n }\n }\n\n### Python\n\n\nBefore trying this sample, follow the Python setup instructions in the\n[BigQuery quickstart using\nclient libraries](/bigquery/docs/quickstarts/quickstart-client-libraries).\n\n\nFor more information, see the\n[BigQuery Python API\nreference documentation](/python/docs/reference/bigquery/latest).\n\n\nTo authenticate to BigQuery, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for client libraries](/bigquery/docs/authentication#client-libs).\n\n from google.cloud import https://cloud.google.com/python/docs/reference/bigquery/latest/\n from google.cloud.exceptions import NotFound\n\n client = https://cloud.google.com/python/docs/reference/bigquery/latest/.https://cloud.google.com/python/docs/reference/bigquery/latest/google.cloud.bigquery.client.Client.html()\n\n # TODO(developer): Set dataset_id to the ID of the dataset to determine existence.\n # dataset_id = \"your-project.your_dataset\"\n\n try:\n client.https://cloud.google.com/python/docs/reference/bigquery/latest/google.cloud.bigquery.client.Client.html#google_cloud_bigquery_client_Client_get_dataset(dataset_id) # Make an API request.\n print(\"Dataset {} already exists\".format(dataset_id))\n except NotFound:\n print(\"Dataset {} is not found\".format(dataset_id))\n\nWhat's next\n-----------\n\n\nTo search and filter code samples for other Google Cloud products, see the\n[Google Cloud sample browser](/docs/samples?product=bigquery)."]]
