Mapper | ScyllaDB Docs

Mapper¶

mapping~Mapper(client, optionsopt)

Represents an object mapper for Apache Cassandra and DataStax Enterprise.

Constructor¶

new Mapper(client, optionsopt)

Creates a new instance of Mapper.

Parameters:

Name	Type	Attributes	Description
`client`	Client		The Client instance to use to execute the queries and fetch the metadata.
`options`	MappingOptions	<optional>	The MappingOptions containing the information of the models and table mappings.

Source

mapping/mapper.js, line 44

Examples

Creating a Mapper instance with some options for the model 'User'

const mappingOptions = {
  models: {
    'User': {
      tables: ['users'],
      mappings: new UnderscoreCqlToCamelCaseMappings(),
      columnNames: {
        'userid': 'id'
      }
    }
  }
};
const mapper = new Mapper(client, mappingOptions);

Creating a Mapper instance with other possible options for a model

const mappingOptions = {
  models: {
    'Video': {
      tables: ['videos', 'user_videos', 'latest_videos', { name: 'my_videos_view', isView: true }],
      mappings: new UnderscoreCqlToCamelCaseMappings(),
      columnNames: {
        'videoid': 'id'
      },
      keyspace: 'ks1'
    }
  }
};
const mapper = new Mapper(client, mappingOptions);

Members¶

client :Client

The Client instance used to create this Mapper instance.

Type:

Client

Source

mapping/mapper.js, line 60

Methods¶

batch(items, executionOptionsopt) → {Promise:.<Result:>}

Executes a batch of queries represented in the items.

Parameters:

Name Type Attributes Description

items Array:.<ModelBatchItem:>

executionOptions

Object | String

An object containing the options to be used for the requests execution or a string representing the name of the execution profile.

Properties

Name	Type	Attributes	Default	Description
`executionProfile`	String	<optional>		The name of the execution profile.
`isIdempotent`	Boolean	<optional>		Defines whether the query can be applied multiple times without changing the result beyond the initial application. The mapper uses the generated queries to determine the default value. When an UPDATE is generated with a counter column or appending/prepending to a list column, the execution is marked as not idempotent. Additionally, the mapper uses the safest approach for queries with lightweight transactions (Compare and Set) by considering them as non-idempotent. Lightweight transactions at client level with transparent retries can break linearizability. If that is not an issue for your application, you can manually set this field to true.
`logged`	Boolean	<optional>	true	Determines whether the batch should be written to the batchlog.
`timestamp`	Number \| Long	<optional>		The default timestamp for the query in microseconds from the unix epoch (00:00:00, January 1st, 1970).

Source

mapping/mapper.js, line 139

Returns:

A Promise that resolves to a Result.

Type: Promise:.<Result:>

forModel(name) → {ModelMapper}

Gets a ModelMapper that is able to map documents of a certain model into CQL rows.

Parameters:

Name	Type	Description
`name`	String	The name to identify the model. Note that the name is case-sensitive.

Source

mapping/mapper.js, line 75

Returns:

A ModelMapper instance.

Type: ModelMapper

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