Writing to MongoDB using `DBWriter`¶

For writing data to MongoDB, use DBWriter.

Warning

Please take into account MongoDB types

Examples¶

from onetl.connection import MongoDB
from onetl.db import DBWriter

mongodb = MongoDB(...)

df = ...  # data is here

writer = DBWriter(
    connection=mongodb,
    target="schema.table",
    options=MongoDB.WriteOptions(
        if_exists="append",
    ),
)

writer.run(df)

Write options¶

Method above accepts MongoDB.WriteOptions

`MongoDBWriteOptions` ¶

Bases: GenericOptions

Writing options for MongoDB connector.

Warning

Options uri, database, collection are populated from connection attributes, and cannot be overridden by the user in WriteOptions to avoid issues.

Added in 0.7.0

Examples:

Note

You can pass any value supported by connector, even if it is not mentioned in this documentation. Option names should be in camelCase!

The set of supported options depends on connector version.

from onetl.connection import MongoDB

options = MongoDB.WriteOptions(
    if_exists="append",
    sampleSize=500,
    localThreshold=20,
)

`if_exists = Field(default=(MongoDBCollectionExistBehavior.APPEND), alias=(avoid_alias('mode')))` `class-attribute` `instance-attribute` ¶

Behavior of writing data into existing collection.

Possible values:

append (default) Adds new objects into existing collection.
Behavior in details
- Collection does not exist Collection is created using options provided by user (shardkey and others).
- Collection exists Data is appended to a collection.
  
  Warning
  
  This mode does not check whether collection already contains objects from dataframe, so duplicated objects can be created.
replace_entire_collection Collection is deleted and then created.
Behavior in details
- Collection does not exist Collection is created using options provided by user (shardkey and others).
- Collection exists Collection content is replaced with dataframe content.
ignore Ignores the write operation if the collection already exists.
Behavior in details
- Collection does not exist Collection is created using options provided by user
- Collection exists The write operation is ignored, and no data is written to the collection.
error Raises an error if the collection already exists.
Behavior in details
- Collection does not exist Collection is created using options provided by user
- Collection exists An error is raised, and no data is written to the collection.

Changed in 0.9.0

Renamed mode → if_exists

Writing to MongoDB using DBWriter¶