Databricks SQL Connector for Python

The Databricks SQL Connector for Python is a Python library that allows you to use Python code to run SQL commands on Databricks clusters and Databricks SQL warehouses. The Databricks SQL Connector for Python is easier to set up and use than similar Python libraries such as pyodbc. This library follows PEP 249 – Python Database API Specification v2.0.

Note

The Databricks SQL Connector for Python also includes a SQLAlchemy dialect for Databricks. See Use SQLAlchemy with Databricks.

Requirements

  • A development machine running Python >=3.8 and <=3.11.

  • Databricks recommends that you use Python virtual environments, such as those provided by venv that are included with Python. Virtual environments help to ensure that you are using the correct versions of Python and the Databricks SQL Connector for Python together. Setting up and using virtual environments is outside of the scope of this article. For more information, see Creating virtual environments.

  • An existing cluster or SQL warehouse.

Get started

  • Install the Databricks SQL Connector for Python library on your development machine by running pip install databricks-sql-connector or python -m pip install databricks-sql-connector.

  • Gather the following information for the cluster or SQL warehouse that you want to use:

    • The server hostname of the SQL warehouse. You can get this from the Server Hostname value in the Connection Details tab for your SQL warehouse.

    • The HTTP path of the SQL warehouse. You can get this from the HTTP Path value in the Connection Details tab for your SQL warehouse.

Authentication

The Databricks SQL Connector for Python supports the following Databricks authentication types:

The Databricks SQL Connector for Python does not yet support the following Databricks authentication types:

Databricks personal access token authentication

To use the Databricks SQL Connector for Python with Databricks personal access token authentication, you must first create a Databricks personal access token, as follows:

  1. In your Databricks workspace, click your Databricks username in the top bar, and then select User Settings from the drop down.

  2. Click Developer.

  3. Next to Access tokens, click Manage.

  4. Click Generate new token.

  5. (Optional) Enter a comment that helps you to identify this token in the future, and change the token’s default lifetime of 90 days. To create a token with no lifetime (not recommended), leave the Lifetime (days) box empty (blank).

  6. Click Generate.

  7. Copy the displayed token to a secure location, and then click Done.

Note

Be sure to save the copied token in a secure location. Do not share your copied token with others. If you lose the copied token, you cannot regenerate that exact same token. Instead, you must repeat this procedure to create a new token. If you lose the copied token, or you believe that the token has been compromised, Databricks strongly recommends that you immediately delete that token from your workspace by clicking the trash can (Revoke) icon next to the token on the Access tokens page.

If you are not able to create or use tokens in your workspace, this might be because your workspace administrator has disabled tokens or has not given you permission to create or use tokens. See your workspace administrator or the following:

To authenticate the Databricks SQL Connector for Python, use the following code snippet. This snippet assumes that you have set the following environment variables:

  • DATABRICKS_SERVER_HOSTNAMEset to the Server Hostname value for your cluster or SQL warehouse.

  • DATABRICKS_HTTP_PATH, set to HTTP Path value for your cluster or SQL warehouse.

  • DATABRICKS_TOKEN, set to the Databricks personal access token.

To set environment variables, see your operating system’s documentation.

from databricks import sql
import os

with sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                 http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                 access_token    = os.getenv("DATABRICKS_TOKEN")) as connection:
# ...

OAuth machine-to-machine (M2M) authentication

Databricks SQL Connector for Python versions 2.7.0 and above support OAuth machine-to-machine (M2M) authentication. You must also install the Databricks SDK for Python 0.18.0 or above (for example by running pip install databricks-sdk or python -m pip install databricks-sdk).

To use the Databricks SQL Connector for Python with OAuth M2M authentication, you must do the following:

  1. Create a Databricks service principal in your Databricks workspace, and create an OAuth secret for that service principal.

    To create the service principal and its OAuth secret, see OAuth machine-to-machine (M2M) authentication. Make a note of the service principal’s UUID or Application ID value, and the Secret value for the service principal’s OAuth secret.

  2. Give that service principal access to your cluster or warehouse.

    To give the service principal access to your cluster or warehouse, see Compute permissions or Manage a SQL warehouse.

To authenticate the Databricks SQL Connector for Python, use the following code snippet. This snippet assumes that you have set the following environment variables:

  • DATABRICKS_SERVER_HOSTNAME set to the Server Hostname value for your cluster or SQL warehouse.

  • DATABRICKS_HTTP_PATH, set to HTTP Path value for your cluster or SQL warehouse.

  • DATABRICKS_CLIENT_ID, set to the service principal’s UUID or Application ID value.

  • DATABRICKS_CLIENT_SECRET, set to the Secret value for the service principal’s OAuth secret.

To set environment variables, see your operating system’s documentation.

from databricks.sdk.core import Config, oauth_service_principal
from databricks import sql
import os

server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME")

def credential_provider():
  config = Config(
    host          = f"https://{server_hostname}",
    client_id     = os.getenv("DATABRICKS_CLIENT_ID"),
    client_secret = os.getenv("DATABRICKS_CLIENT_SECRET"))
  return oauth_service_principal(config)

with sql.connect(server_hostname      = server_hostname,
                 http_path            = os.getenv("DATABRICKS_HTTP_PATH"),
                 credentials_provider = credential_provider) as connection:
# ...

OAuth user-to-machine (U2M) authentication

Databricks SQL Connector for Python versions 3.0.3 and above support OAuth user-to-machine (U2M) authentication. You must also install the Databricks SDK for Python 0.19.0 or above (for example by running pip install databricks-sdk or python -m pip install databricks-sdk).

To authenticate the Databricks SQL Connector for Python with OAuth U2M authentication, use the following code snippet. OAuth U2M authentication uses real-time human sign-in and consent to authenticate the target Databricks user account. This snippet assumes that you have set the following environment variables:

  • Set DATABRICKS_SERVER_HOSTNAME to the Server Hostname value for your cluster or SQL warehouse.

  • Set DATABRICKS_HTTP_PATH to HTTP Path value for your cluster or SQL warehouse.

To set environment variables, see your operating system’s documentation.

from databricks import sql
import os

with sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                 http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                 auth_type       = "databricks-oauth") as connection:
# ...

Examples

The following code examples demonstrate how to use the Databricks SQL Connector for Python to query and insert data, query metadata, manage cursors and connections, and configure logging.

Note

The following code examples demonstrate how to use a Databricks personal access token for authentication. To use other available Databricks authentication types instead, see Authentication.

These code example retrieve their server_hostname, http_path, and access_token connection variable values from these environment variables:

  • DATABRICKS_SERVER_HOSTNAME, which represents the Server Hostname value from the requirements.

  • DATABRICKS_HTTP_PATH, which represents the HTTP Path value from the requirements.

  • DATABRICKS_TOKEN, which represents your access token from the requirements.

You can use other approaches to retrieving these connection variable values. Using environment variables is just one approach among many.

Query data

The following code example demonstrates how to call the Databricks SQL Connector for Python to run a basic SQL command on a cluster or SQL warehouse. This command returns the first two rows from the trips table in the samples catalog’s nyctaxi schema.

from databricks import sql
import os

with sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                 http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                 access_token    = os.getenv("DATABRICKS_TOKEN")) as connection:

  with connection.cursor() as cursor:
    cursor.execute("SELECT * FROM samples.nyctaxi.trips LIMIT 2")
    result = cursor.fetchall()

    for row in result:
      print(row)

Insert data

The following example demonstrate how to insert small amounts of data (thousands of rows):

from databricks import sql
import os

with sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                 http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                 access_token    = os.getenv("DATABRICKS_TOKEN")) as connection:

  with connection.cursor() as cursor:
    cursor.execute("CREATE TABLE IF NOT EXISTS squares (x int, x_squared int)")

    squares = [(i, i * i) for i in range(100)]
    values = ",".join([f"({x}, {y})" for (x, y) in squares])

    cursor.execute(f"INSERT INTO squares VALUES {values}")

    cursor.execute("SELECT * FROM squares LIMIT 10")

    result = cursor.fetchall()

    for row in result:
      print(row)

For large amounts of data, you should first upload the data to cloud storage and then execute the COPY INTO command.

Query metadata

There are dedicated methods for retrieving metadata. The following example retrieves metadata about columns in a sample table:

from databricks import sql
import os

with sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                 http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                 access_token    = os.getenv("DATABRICKS_TOKEN")) as connection:

  with connection.cursor() as cursor:
    cursor.columns(schema_name="default", table_name="squares")
    print(cursor.fetchall())

Manage cursors and connections

It is a best practice to close any connections and cursors that are no longer in use. This frees resources on Databricks clusters and Databricks SQL warehouses.

You can use a context manager (the with syntax used in previous examples) to manage the resources, or explicitly call close:

from databricks import sql
import os

connection = sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                         http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                         access_token    = os.getenv("DATABRICKS_TOKEN"))

cursor = connection.cursor()

cursor.execute("SELECT * from range(10)")
print(cursor.fetchall())

cursor.close()
connection.close()

Configure logging

The Databricks SQL Connector uses Python’s standard logging module. You can configure the logging level similar to the following:

from databricks import sql
import os, logging

logging.getLogger("databricks.sql").setLevel(logging.DEBUG)
logging.basicConfig(filename = "results.log",
                    level    = logging.DEBUG)

connection = sql.connect(server_hostname = os.getenv("DATABRICKS_SERVER_HOSTNAME"),
                         http_path       = os.getenv("DATABRICKS_HTTP_PATH"),
                         access_token    = os.getenv("DATABRICKS_TOKEN"))

cursor = connection.cursor()

cursor.execute("SELECT * from range(10)")

result = cursor.fetchall()

for row in result:
   logging.debug(row)

cursor.close()
connection.close()

API reference

Package

databricks-sql-connector

Usage: pip install databricks-sql-connector

See also databricks-sql-connector in the Python Package Index (PyPI).

Module

databricks.sql

Usage: from databricks import sql

Methods

connect method

Creates a connection to a database.

Returns a Connection object.

Parameters

server_hostname

Type: str

The server hostname for the cluster. To get the server hostname, see the instructions earlier in this article.

This parameter is required.

Example: 1234567890123456.7.gcp.databricks.com

http_path

Type: str

The HTTP path of the cluster. To get the HTTP path, see the instructions earlier in this article.

This parameter is required.

sql/protocolv1/o/1234567890123456/1234-567890-test123 for a cluster. /sql/1.0/warehouses/a1b234c567d8e9fa for a SQL warehouse.

access_token

Type: str

Your Databricks personal access token for the workspace for the cluster. To create a token, see the instructions earlier in this article.

This parameter is required.

Example: dapi...<the-remaining-portion-of-your-token>

session_configuration

Type: dict[str, Any]

A dictionary of Spark session configuration parameters. Setting a configuration is equivalent to using the SET key=val SQL command. Run the SQL command SET -v to get a full list of available configurations.

Defaults to None.

This parameter is optional.

Example: {"spark.sql.variable.substitute": True}

http_headers

Type: List[Tuple[str, str]]]

Additional (key, value) pairs to set in HTTP headers on every RPC request the client makes. Typical usage will not set any extra HTTP headers. Defaults to None.

This parameter is optional.

Since version 2.0

catalog

Type: str

Initial catalog to use for the connection. Defaults to None (in which case the default catalog, typically hive_metastore will be used).

This parameter is optional.

Since version 2.0

schema

Type: str

Initial schema to use for the connection. Defaults to None (in which case the default schema default will be used).

This parameter is optional.

Since version 2.0

use_cloud_fetch

Type: bool

True to send fetch requests directly to the cloud object store to download chunks of data. False (the default) to send fetch requests directly to Databricks.

If use_cloud_fetch is set to True but network access is blocked, then the fetch requests will fail.

Since version 2.8

Classes

Connection class

Represents a connection to a database.

Methods
close method

Closes the connection to the database and releases all associated resources on the server. Any additional calls to this connection will throw an Error.

No parameters.

No return value.

cursor method

Returns a mechanism that enables traversal over the records in a database.

No parameters.

Returns a Cursor object.

Cursor class

Attributes
arraysize attribute

Used with the fetchmany method, specifies the internal buffer size, which is also how many rows are actually fetched from the server at a time. The default value is 10000. For narrow results (results in which each row does not contain a lot of data), you should increase this value for better performance.

Read-write access.

description attribute

Contains a Python list of tuple objects. Each of these tuple objects contains 7 values, with the first 2 items of each tuple object containing information describing a single result column as follows:

  • name: The name of the column.

  • type_code: A string representing the type of the column. For example, an integer column will have a type code of int.

The remaining 5 items of each 7-item tuple object are not implemented, and their values are not defined. They will typically be returned as 4 None values followed by a single True value.

Read-only access.

Methods
cancel method

Interrupts the running of any database query or command that the cursor has started. To release the associated resources on the server, call the close method after calling the cancel method.

No parameters.

No return value.

close method

Closes the cursor and releases the associated resources on the server. Closing an already closed cursor might throw an error.

No parameters.

No return value.

execute method

Prepares and then runs a database query or command.

No return value.

Parameters

operation

Type: str

The query or command to prepare and then run.

This parameter is required.

Example without the parameters parameter:

cursor.execute(
 'SELECT * FROM samples.nyctaxi.trips WHERE pickup_zip="10019" LIMIT 2'
)

Example with the parameters parameter:

cursor.execute(
 'SELECT * FROM samples.nyctaxi.trips WHERE zip=%(pickup_zip)s LIMIT 2',
 { 'pickup_zip': '10019' }
)

parameters

Type: dictionary

A sequence of parameters to use with the operation parameter.

This parameter is optional. The default is None.

executemany method

Prepares and then runs a database query or command using all parameter sequences in the seq_of_parameters argument. Only the final result set is retained.

No return value.

Parameters

operation

Type: str

The query or command to prepare and then run.

This parameter is required.

seq_of_parameters

Type: list of dict

A sequence of many sets of parameter values to use with the operation parameter.

This parameter is required.

catalogs method

Execute a metadata query about the catalogs. Actual results should then be fetched using fetchmany or fetchall. Important fields in the result set include:

  • Field name: TABLE_CAT. Type: str. The name of the catalog.

No parameters.

No return value.

Since version 1.0

schemas method

Execute a metadata query about the schemas. Actual results should then be fetched using fetchmany or fetchall. Important fields in the result set include:

  • Field name: TABLE_SCHEM. Type: str. The name of the schema.

  • Field name: TABLE_CATALOG. Type: str. The catalog to which the schema belongs.

No return value.

Since version 1.0

Parameters

catalog_name

Type: str

A catalog name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

schema_name

Type: str

A schema name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

tables method

Execute a metadata query about tables and views. Actual results should then be fetched using fetchmany or fetchall. Important fields in the result set include:

  • Field name: TABLE_CAT. Type: str. The catalog to which the table belongs.

  • Field name: TABLE_SCHEM. Type: str. The schema to which the table belongs.

  • Field name: TABLE_NAME. Type: str. The name of the table.

  • Field name: TABLE_TYPE. Type: str. The kind of relation, for example VIEW or TABLE (applies to Databricks Runtime 10.2 and above; prior versions of the Databricks Runtime return an empty string).

No return value.

Since version 1.0

Parameters

catalog_name

Type: str

A catalog name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

schema_name

Type: str

A schema name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

table_name

Type: str

A table name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

table_types

Type: List[str]

A list of table types to match, for example TABLE or VIEW.

This parameter is optional.

columns method

Execute a metadata query about the columns. Actual results should then be fetched using fetchmany or fetchall. Important fields in the result set include:

  • Field name: TABLE_CAT. Type: str. The catalog to which the column belongs.

  • Field name: TABLE_SCHEM. Type: str. The schema to which the column belongs.

  • Field name: TABLE_NAME. Type: str. The name of the table to which the column belongs.

  • Field name: COLUMN_NAME. Type: str. The name of the column.

No return value.

Since version 1.0

Parameters

catalog_name

Type: str

A catalog name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

schema_name

Type: str

A schema name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

table_name

Type: str

A table name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

column_name

Type: str

A column name to retrieve information about. The % character is interpreted as a wildcard.

This parameter is optional.

fetchall method

Gets all (or all remaining) rows of a query.

No parameters.

Returns all (or all remaining) rows of the query as a Python list of Row objects.

Throws an Error if the previous call to the execute method did not return any data or no execute call has yet been made.

fetchmany method

Gets the next rows of a query.

Returns up to size (or the arraysize attribute if size is not specified) of the next rows of a query as a Python list of Row objects. If there are fewer than size rows left to be fetched, all remaining rows will be returned.

Throws an Error if the previous call to the execute method did not return any data or no execute call has yet been made.

Parameters

size

Type: int

The number of next rows to get.

This parameter is optional. If not specified, the value of the arraysize attribute is used.

Example: cursor.fetchmany(10)

fetchone method

Gets the next row of the dataset.

No parameters.

Returns the next row of the dataset as a single sequence as a Python tuple object, or returns None if there is no more available data.

Throws an Error if the previous call to the execute method did not return any data or no execute call has yet been made.

fetchall_arrow method

Gets all (or all remaining) rows of a query, as a PyArrow Table object. Queries returning very large amounts of data should use fetchmany_arrow instead to reduce memory consumption.

No parameters.

Returns all (or all remaining) rows of the query as a PyArrow table.

Throws an Error if the previous call to the execute method did not return any data or no execute call has yet been made.

Since version 2.0

fetchmany_arrow method

Gets the next rows of a query as a PyArrow Table object.

Returns up to the size argument (or the arraysize attribute if size is not specified) of the next rows of a query as a Python PyArrow Table object.

Throws an Error if the previous call to the execute method did not return any data or no execute call has yet been made.

Since version 2.0

Parameters

size

Type: int

The number of next rows to get.

This parameter is optional. If not specified, the value of the arraysize attribute is used.

Example: cursor.fetchmany_arrow(10)

Row class

The row class is a tuple-like data structure that represents an individual result row. If the row contains a column with the name "my_column", you can access the "my_column" field of row via row.my_column. You can also use numeric indicies to access fields, for example row[0]. If the column name is not allowed as an attribute method name (for example, it begins with a digit), then you can access the field as row["1_my_column"].

Since version 1.0

Methods
asDict method

Return a dictionary representation of the row, which is indexed by field names. If there are duplicate field names, one of the duplicate fields (but only one) will be returned in the dictionary. Which duplicate field is returned is not defined.

No parameters.

Returns a dict of fields.

Type conversions

The following table maps Apache Spark SQL data types to their Python data type equivalents.

Apache Spark SQL data type

Python data type

array

numpy.ndarray

bigint

int

binary

bytearray

boolean

bool

date

datetime.date

decimal

decimal.Decimal

double

float

int

int

map

str

null

NoneType

smallint

int

string

str

struct

str

timestamp

datetime.datetime

tinyint

int

Troubleshooting

tokenAuthWrapperInvalidAccessToken: Invalid access token message

Issue: When you run your code, you see a message similar to Error during request to server: tokenAuthWrapperInvalidAccessToken: Invalid access token.

Possible cause: The value passed to access_token is not a valid Databricks personal access token.

Recommended fix: Check that the value passed to access_token is correct and try again.

gaierror(8, 'nodename nor servname provided, or not known') message

Issue: When you run your code, you see a message similar to Error during request to server: gaierror(8, 'nodename nor servname provided, or not known').

Possible cause: The value passed to server_hostname is not the correct host name.

Recommended fix: Check that the value passed to server_hostname is correct and try again.

For more information on finding the server hostname, see Get connection details for a Databricks compute resource.

IpAclError message

Issue: When you run your code, you see the message Error during request to server: IpAclValidation when you try to use the connector on a Databricks notebook.

Possible cause: You may have IP allow listing enabled for the Databricks workspace. With IP allow listing, connections from Spark clusters back to the control plane are not allowed by default.

Recommended fix: Ask your administrator to add the compute plane subnet to the IP allow list.

Additional resources

For more information, see: