Managing Snowflake databases, schemas, tables, and views with Python¶
You can use Python to manage Snowflake databases, schemas, tables, and views. For more information about managing and working with data in Snowflake, see Databases, Tables and Views - Overview.
Prerequisites¶
The examples in this topic assume that you’ve added code to connect with Snowflake and to create a Root
object from which to use the
Snowflake Python APIs.
For example, the following code uses connection parameters defined in a configuration file to create a connection to Snowflake:
from snowflake.core import Root
from snowflake.snowpark import Session
session = Session.builder.config("connection_name", "myconnection").create()
root = Root(session)
Using the resulting Session
object, the code creates a Root
object to use the API’s types and methods. For more information,
see Connect to Snowflake with the Snowflake Python APIs.
Managing databases¶
You can manage databases in Snowflake. The Snowflake Python APIs represents databases with two separate types:
Database
: Exposes a database’s properties, such as its name.DatabaseResource
: Exposes methods you can use to fetch a correspondingDatabase
object and to drop the database.
Topics
Creating a database¶
You can create a database by calling the DatabaseCollection.create
method and passing a Database
object that represents the
database you want to create. To create a database, first create a Database
object that specifies the database name.
Code in the following example creates a Database
object representing a database named my_db
and then creates the
database by passing the Database
object to the DatabaseCollection.create
method:
from snowflake.core.database import Database
my_db = Database(name="my_db")
root.databases.create(my_db)
Getting database details¶
You can get information about a database by calling the DatabaseResource.fetch
method, which returns a Database
object.
Code in the following example gets information about a database named my_db
:
my_db = root.databases["my_db"].fetch()
print(my_db.to_dict())
Listing databases¶
You can list databases using the iter
method, which returns a PagedIter
iterator.
Code in the following example lists databases whose name begins with my
:
databases = root.databases.iter(like="my%")
for database in databases:
print(database.name)
Dropping a database¶
You can drop a database using the DatabaseResource.drop
method.
Code in the following example drops the my_db
database:
my_db_res = root.databases["my_db"]
my_db_res.drop()
Managing schemas¶
You can manage schemas in Snowflake. A schema is a database-level object. When you create or reference a schema, you do so in the context of its database.
The Snowflake Python APIs represents schemas with two separate types:
Schema
: Exposes a schema’s properties, such as its name.SchemaResource
: Exposes methods you can use to fetch a correspondingSchema
object and to drop the schema.
Topics
Creating a schema¶
To create a schema, first create a Schema
object that specifies the schema name.
Code in the following example creates a Schema
object representing a schema named my_schema
:
from snowflake.core.schema import Schema
my_schema = Schema(name="my_schema")
root.databases["my_db"].schemas.create(my_schema)
The code then creates the schema in the my_db
database by passing the Schema
object to the SchemaCollection.create
method.
Getting schema details¶
You can get information about a schema by calling the SchemaResource.fetch
method, which returns a Schema
object.
Code in the following example gets a Schema
object that represents the my_schema
schema:
my_schema = root.databases["my_db"].schemas["my_schema"].fetch()
print(my_schema.to_dict())
Listing schemas¶
You can list the schemas in a specified database using the iter
method. The method returns a PagedIter
iterator of
Schema
objects.
Code in the following example lists schema names in the my_db
database:
schema_list = root.databases["my_db"].schemas.iter()
for schema_obj in schema_list:
print(schema_obj.name)
Dropping a schema¶
You can drop a schema using the SchemaResource.drop
method.
Code in the following example drops the my_schema
schema:
my_schema_res = root.databases["my_db"].schemas["my_schema"]
my_schema_res.drop()
Managing standard tables¶
You can manage standard tables in Snowflake. A table is a schema-level object. When you create or reference a table, you do so in the context of its schema.
The Snowflake Python APIs represents tables with two separate types:
Table
: Exposes a table’s properties, such as its name and columns.TableResource
: Exposes methods you can use to fetch a correspondingTable
object, update the properties of the table, and drop the table.
Topics
Creating a table¶
To create a table, first create a Table
object that specifies the table name, column names, and column data types.
Code in the following example creates a Table
object representing a table named my_table
with the specified columns:
from snowflake.core.table import Table, TableColumn
my_table = Table(
name="my_table",
columns=[TableColumn(name="c1", datatype="int", nullable=False),
TableColumn(name="c2", datatype="string")]
)
root.databases["my_db"].schemas["my_schema"].tables.create(my_table)
The code then creates the table in the my_db
database and my_schema
schema by passing the Table
object to the
TableCollection.create
method.
Getting table details¶
You can get information about a table by calling the TableResource.fetch
method, which returns a Table
object.
Code in the following example gets information about a table named my_table
:
my_table = root.databases["my_db"].schemas["my_schema"].tables["my_table"].fetch()
print(my_table.to_dict())
Creating or altering a table¶
You can set properties of a Table
object and pass it to the TableResource.create_or_alter
method to create a table if it
doesn’t exist, or alter it according to the table definition if it does exist. The behavior of create_or_alter
is intended to be
idempotent, which means that the resulting table object will be the same regardless of whether the table exists before you run the method.
Note
The create_or_alter
method uses default values for any Table
properties that you don’t explicitly define. For example, if you don’t set data_retention_time_in_days
, its value defaults to
None
even if the table previously existed with a different value.
Code in the following example appends a new column named c3
of datatype int
to the my_table
table, and then alters the
table in Snowflake:
from snowflake.core.table import PrimaryKey, TableColumn
my_table = root.databases["my_db"].schemas["my_schema"].tables["my_table"].fetch()
my_table.columns.append(TableColumn(name="c3", datatype="int", nullable=False, constraints=[PrimaryKey()]))
my_table_res = root.databases["my_db"].schemas["my_schema"].tables["my_table"]
my_table_res.create_or_alter(my_table)
Listing tables¶
You can list the tables in a specified schema using the iter
method, which returns a PagedIter
iterator of
Table
objects.
Code in the following example lists tables whose name begins with my
:
tables = root.databases["my_db"].schemas["my_schema"].tables.iter(like="my%")
for table_obj in tables:
print(table_obj.name)
Dropping a table¶
You can drop a table using the TableResource.drop
method.
Code in the following example drops the my_table
table:
my_table_res = root.databases["my_db"].schemas["my_schema"].tables["my_table"]
my_table_res.drop()
Managing event tables¶
You can manage Snowflake event tables, which are a special kind of database table with a predefined set of columns where Snowflake can collect telemetry data. For more information, see Event table overview.
The Snowflake Python APIs represents event tables with two separate types:
EventTable
: Exposes an event table’s properties such as its name, data retention time, max data extension time, and change tracking option.EventTableResource
: Exposes methods you can use to fetch a correspondingEventTable
object, rename the event table, and drop the event table.
Topics
Creating an event table¶
To create an event table, first create a EventTable
object, and then create a EventTableCollection
object from the API
Root
object. Using EventTableCollection.create
, add the new event table to Snowflake.
Code in the following example creates a EventTable
object that represents an event table named my_event_table
with the
specified parameters:
from snowflake.core.event_table import EventTable
event_table = EventTable(
name="my_event_table",
data_retention_time_in_days = 3,
max_data_extension_time_in_days = 5,
change_tracking = True,
default_ddl_collation = 'EN-CI',
comment = 'CREATE EVENT TABLE'
)
event_tables = root.databases["my_db"].schemas["my_schema"].event_tables
event_tables.create(my_event_table)
The code creates a EventTableCollection
variable event_tables
and uses EventTableCollection.create
to create a new
event table in Snowflake.
Getting event table details¶
You can get information about an event table by calling the EventTableResource.fetch
method, which returns a EventTable
object.
Code in the following example gets information about an event table named my_event_table
:
my_event_table = root.databases["my_db"].schemas["my_schema"].event_tables["my_event_table"].fetch()
print(my_event_table.to_dict())
Listing event tables¶
You can list event tables using the EventTableCollection.iter
method, which returns a PagedIter
iterator of
EventTable
objects.
Code in the following example lists event tables whose name starts with my
in the my_db
database and my_schema
schema, and
prints the name of each:
from snowflake.core.event_table import EventTableCollection
event_tables: EventTableCollection = root.databases["my_db"].schemas["my_schema"].event_tables
event_table_iter = event_tables.iter(like="my%") # returns a PagedIter[EventTable]
for event_table_obj in event_table_iter:
print(event_table_obj.name)
Code in the following example also lists event tables whose name begins with my
, but it uses the starts_with
parameter instead
of like
. This example also sets the optional parameter show_limit=10
to limit the number of results to 10
:
event_tables: EventTableCollection = root.databases["my_db"].schemas["my_schema"].event_tables
event_table_iter = event_tables.iter(starts_with="my", show_limit=10)
for event_table_obj in event_table_iter:
print(event_table_obj.name)
Performing event table operations¶
You can perform common event table operations—such as renaming an event table and dropping an event table—with a
EventTableResource
object.
Note
Only the RENAME functionality of ALTER TABLE (event tables) is currently supported.
RENAME is not supported on the default event table, SNOWFLAKE.TELEMETRY.EVENTS.
To demonstrate operations you can do with an event table resource, code in the following example does the following:
Fetches the
my_event_table
event table resource object.Renames the event table.
Drops the event table.
my_event_table_res = root.databases["my_db"].schemas["my_schema"].event_tables["my_event_table"]
my_event_table_res.rename("my_other_event_table")
my_event_table_res.drop()
Managing views¶
You can manage views in Snowflake. A view is a schema-level object and allows the result of a query to be accessed as if it were a table. When you create or reference a view, you do so in the context of its schema.
Note
ALTER VIEW is currently not supported.
The Snowflake Python APIs represents views with two separate types:
View
: Exposes a view’s properties, such as its name, columns, and SQL query statement.ViewResource
: Exposes methods you can use to fetch a correspondingView
object and to drop the view.
Topics
Creating a view¶
To create a view, first create a View
object that specifies the view name, columns, and SQL query statement.
Code in the following example creates a View
object representing a view named my_view
with the specified columns and SQL
query:
from snowflake.core.view import View, ViewColumn
my_view = View(
name="my_view",
columns=[
ViewColumn(name="c1"), ViewColumn(name="c2"), ViewColumn(name="c3"),
],
query="SELECT * FROM my_table",
)
root.databases["my_db"].schemas["my_schema"].views.create(my_view)
The code then creates the view in the my_db
database and my_schema
schema by passing the View
object to the
ViewCollection.create
method.
Getting view details¶
You can get information about a view by calling the ViewResource.fetch
method, which returns a View
object.
Code in the following example gets a View
object that represents the my_view
view:
my_view = root.databases["my_db"].schemas["my_schema"].views["my_view"].fetch()
print(my_view.to_dict())
Listing views¶
You can list the views in a specified database using the iter
method. The method returns a PagedIter
iterator of
View
objects.
Code in the following example lists views whose name begins with my
in the my_db
database and my_schema
schema:
view_list = root.databases["my_db"].schemas["my_schema"].views.iter(like="my%")
for view_obj in view_list:
print(view_obj.name)
Code in the following example also lists views whose name begins with my
, but it uses the starts_with
parameter instead of
like
. This example also sets the optional parameter show_limit=10
to limit the number of results to 10
:
view_list = root.databases["my_db"].schemas["my_schema"].views.iter(starts_with="my", show_limit=10)
for view_obj in view_list:
print(view_obj.name)
Dropping a view¶
You can drop a view using the ViewResource.drop
method.
Code in the following example drops the my_view
view:
my_view_res = root.databases["my_db"].schemas["my_schema"].views["my_view"]
my_view_res.drop()