Update a row (Python)

Tables with the Data API are currently in public preview. Development is ongoing, and the features and functionality are subject to change. Hyper-Converged Database (HCD), and the use of such, is subject to the DataStax Preview Terms.

Updates a single row in a table.

If the row does not already exist and the update includes at least one non-null or non-empty value, creates a new row.

For general information about working with tables and rows, see About tables with the Data API (Python).

Ready to write code? See the examples for this method to get started. If you are new to the Data API, check out the quickstart.

Result

Updates the specified row.

If no row matches the specified primary key and the update includes at least one non-null or non-empty value, then a new row is created with the values specified $set values and primary key values. Any omitted or $unset columns are set to null in the new row.

Does not return anything.

A rare edge case, related to underlying Apache Cassandra® functionality, can cause a row to disappear altogether when all of its columns are set to null.

This happens if the row was previously created from an update operation that had no pre-existing row to modify.

Parameters

Use the update_one method, which belongs to the astrapy.Table class.

Method signature

update_one(
  filter: Dict[str, Any],
  update: Dict[str, Any],
  *,
  general_method_timeout_ms: int,
  request_timeout_ms: int,
  timeout_ms: int,
) -> None

Name Type Summary

Name	Type	Summary
`filter`	`Dict[str, Any]`	Describes the full primary key of the row to update. For this method, the filter can only use the `$eq` operator and columns in the primary key.
`update`	`Dict[str, Any]`	Defines the update using Data API operators. For a list of available operators and more examples, see Update operators for tables (Python). You cannot update primary key values. If you need to modify a row’s primary key, delete the row and then insert a new row with the desired primary key values.
`general_method_timeout_ms`	`int`	Optional. The maximum time, in milliseconds, that the client should wait for the underlying HTTP request. This parameter is aliased as `request_timeout_ms` and `timeout_ms` for convenience. Default: The default value for the table. This default is 30 seconds unless you specified a different default when you initialized the `Table` or `DataAPIClient` object. For more information, see Timeout options.

filter

Dict[str, Any]

Describes the full primary key of the row to update.

For this method, the filter can only use the $eq operator and columns in the primary key.

update

Dict[str, Any]

Defines the update using Data API operators.

For a list of available operators and more examples, see Update operators for tables (Python).

You cannot update primary key values. If you need to modify a row’s primary key, delete the row and then insert a new row with the desired primary key values.

general_method_timeout_ms

int

Optional. The maximum time, in milliseconds, that the client should wait for the underlying HTTP request.

This parameter is aliased as request_timeout_ms and timeout_ms for convenience.

Default: The default value for the table. This default is 30 seconds unless you specified a different default when you initialized the Table or DataAPIClient object. For more information, see Timeout options.

Examples

The following examples demonstrate how to update a row in a table.

Update multiple columns

You can combine multiple operators and properties in a single call. For the full list of operators, see Update operators for tables (Python).

If the row does not already exist and the update includes at least one non-null or non-empty value, creates a new row.

The following example uses untyped documents or rows, but you can define a client-side type for your collection to help statically catch errors. For examples, see Typing support.

from astrapy import DataAPIClient
from astrapy.authentication import UsernamePasswordTokenProvider
from astrapy.constants import Environment

# Get an existing table
client = DataAPIClient(environment=Environment.HCD)
database = client.get_database(
    "API_ENDPOINT",
    token=UsernamePasswordTokenProvider("USERNAME", "PASSWORD"),
    keyspace="KEYSPACE_NAME",
)
table = database.get_table("TABLE_NAME")

# Update a row
table.update_one(
    {"title": "Hidden Shadows of the Past", "author": "John Anthony"},
    {
        "$set": {"rating": 4.5, "genres": ["Fiction", "Drama"]},
        "$unset": {"borrower": ""},
    },
)

Unset columns

To unset a column, you can use the $unset operator, or you can use the $set operator and an empty value. Either operation will delete the value in the specified column.

Unsetting a column produces a tombstone. Excessive tombstones can impact query performance.

The following example uses untyped documents or rows, but you can define a client-side type for your collection to help statically catch errors. For examples, see Typing support.

from astrapy import DataAPIClient
from astrapy.authentication import UsernamePasswordTokenProvider
from astrapy.constants import Environment

# Get an existing table
client = DataAPIClient(environment=Environment.HCD)
database = client.get_database(
    "API_ENDPOINT",
    token=UsernamePasswordTokenProvider("USERNAME", "PASSWORD"),
    keyspace="KEYSPACE_NAME",
)
table = database.get_table("TABLE_NAME")

# Update a row
table.update_one(
    {"title": "Hidden Shadows of the Past", "author": "John Anthony"},
    {"$unset": {"genres": ""}},
)

Client reference

For more information, see the client reference.

Update a row (Python)

Result

Parameters

Examples

Update multiple columns

Unset columns

Client reference

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