Schema

The schema APIs

Schema in RedisVL provides a structured format to define index settings and field configurations using the following three components:

IndexSchema

class IndexSchema(*, index, fields={}, version='0.1.0')

A schema definition for a search index in Redis, used in RedisVL for configuring index settings and organizing vector and metadata fields.

The class offers methods to create an index schema from a YAML file or a Python dictionary, supporting flexible schema definitions and easy integration into various workflows.

An example schema.yaml file might look like this:

version: '0.1.0'

index:
    name: user-index
    prefix: user
    key_separator: ":"
    storage_type: json

fields:
    - name: user
      type: tag
    - name: credit_score
      type: tag
    - name: embedding
      type: vector
      attrs:
        algorithm: flat
        dims: 3
        distance_metric: cosine
        datatype: float32

Loading the schema for RedisVL from yaml is as simple as:

from redisvl.schema import IndexSchema

schema = IndexSchema.from_yaml("schema.yaml")

Loading the schema for RedisVL from dict is as simple as:

from redisvl.schema import IndexSchema

schema = IndexSchema.from_dict({
    "index": {
        "name": "user-index",
        "prefix": "user",
        "key_separator": ":",
        "storage_type": "json",
    },
    "fields": [
        {"name": "user", "type": "tag"},
        {"name": "credit_score", "type": "tag"},
        {
            "name": "embedding",
            "type": "vector",
            "attrs": {
                "algorithm": "flat",
                "dims": 3,
                "distance_metric": "cosine",
                "datatype": "float32"
            }
        }
    ]
})

Create a new model by parsing and validating input data from keyword arguments.

Raises ValidationError if the input data cannot be parsed to form a valid model.

• Parameters:
  • index (IndexInfo) –
  • fields (Dict *[*str , BaseField ]) –
  • version (str) –

add_field(field_inputs)

Adds a single field to the index schema based on the specified field type and attributes.

This method allows for the addition of individual fields to the schema, providing flexibility in defining the structure of the index.

• Parameters: field_inputs (Dict *[*str , Any ]) – A field to add.
• Raises: ValueError – If the field name or type are not provided or if the name already exists within the schema.

# Add a tag field
schema.add_field({"name": "user", "type": "tag})

# Add a vector field
schema.add_field({
    "name": "user-embedding",
    "type": "vector",
    "attrs": {
        "dims": 1024,
        "algorithm": "flat",
        "datatype": "float32"
    }
})

add_fields(fields)

Extends the schema with additional fields.

This method allows dynamically adding new fields to the index schema. It processes a list of field definitions.

• Parameters: fields (List *[*Dict *[*str , Any ] ]) – A list of fields to add.
• Raises: ValueError – If a field with the same name already exists in the schema.

schema.add_fields([
    {"name": "user", "type": "tag"},
    {"name": "bio", "type": "text"},
    {
        "name": "user-embedding",
        "type": "vector",
        "attrs": {
            "dims": 1024,
            "algorithm": "flat",
            "datatype": "float32"
        }
    }
])

classmethod from_dict(data)

Create an IndexSchema from a dictionary.

• Parameters: data (Dict *[*str , Any ]) – The index schema data.
• Returns: The index schema.
• Return type: IndexSchema

from redisvl.schema import IndexSchema

schema = IndexSchema.from_dict({
    "index": {
        "name": "docs-index",
        "prefix": "docs",
        "storage_type": "hash",
    },
    "fields": [
        {
            "name": "doc-id",
            "type": "tag"
        },
        {
            "name": "doc-embedding",
            "type": "vector",
            "attrs": {
                "algorithm": "flat",
                "dims": 1536
            }
        }
    ]
})

classmethod from_yaml(file_path)

Create an IndexSchema from a YAML file.

• Parameters: file_path (str) – The path to the YAML file.
• Returns: The index schema.
• Return type: IndexSchema

from redisvl.schema import IndexSchema
schema = IndexSchema.from_yaml("schema.yaml")

remove_field(field_name)

Removes a field from the schema based on the specified name.

This method is useful for dynamically altering the schema by removing existing fields.

• Parameters: field_name (str) – The name of the field to be removed.

to_dict()

Convert the index schema to a dictionary.

• Returns: The index schema as a dictionary.
• Return type: Dict[str, Any]

to_yaml(file_path, overwrite=True)

Write the index schema to a YAML file.

• Parameters:
  • file_path (str) – The path to the YAML file.
  • overwrite (bool) – Whether to overwrite the file if it already exists.
• Raises: FileExistsError – If the file already exists and overwrite is False.
• Return type: None

property field_names : List[str]

A list of field names associated with the index schema.

• Returns: A list of field names from the schema.
• Return type: List[str]

fields : Dict[str, BaseField]

Fields associated with the search index and their properties

index : IndexInfo

Details of the basic index configurations.

version : str

Version of the underlying index schema.

Defining Fields

Fields in the schema can be defined in YAML format or as a Python dictionary, specifying a name, type, an optional path, and attributes for customization.

YAML Example:

- name: title
  type: text
  path: $.document.title
  attrs:
    weight: 1.0
    no_stem: false
    withsuffixtrie: true

Python Dictionary Example:

{
    "name": "location",
    "type": "geo",
    "attrs": {
        "sortable": true
    }
}

Supported Field Types and Attributes

Each field type supports specific attributes that customize its behavior. Below are the field types and their available attributes:

Text Field Attributes:

• weight: Importance of the field in result calculation.
• no_stem: Disables stemming during indexing.
• withsuffixtrie: Optimizes queries by maintaining a suffix trie.
• phonetic_matcher: Enables phonetic matching.
• sortable: Allows sorting on this field.

Tag Field Attributes:

• separator: Character for splitting text into individual tags.
• case_sensitive: Case sensitivity in tag matching.
• withsuffixtrie: Suffix trie optimization for queries.
• sortable: Enables sorting based on the tag field.

Numeric and Geo Field Attributes:

• Both numeric and geo fields support the sortable attribute, enabling sorting on these fields.

Common Vector Field Attributes:

• dims: Dimensionality of the vector.
• algorithm: Indexing algorithm (flat or hnsw).
• datatype: Float datatype of the vector (float32 or float64).
• distance_metric: Metric for measuring query relevance (COSINE, L2, IP).

HNSW Vector Field Specific Attributes:

• m: Max outgoing edges per node in each layer.
• ef_construction: Max edge candidates during build time.
• ef_runtime: Max top candidates during search.
• epsilon: Range search boundary factor.

Note:

See fully documented Redis-supported fields and options here: FT.CREATE.