LanceDB · Schema

LanceDB Table

A Lance table inside a LanceDB namespace. Tables are columnar (Lance format), versioned, and may carry vector, full-text, and scalar indexes.

Vector DatabaseMultimodalLance FormatLakehouseRAGAgent MemoryOpen SourceEmbeddingsFull-Text SearchHybrid SearchColumnar StorageArrowAI Infrastructure

Properties

Name	Type	Description
name	string	Table identifier within its namespace.
namespace	array	Hierarchical namespace path (e.g. ['warehouse', 'project']).
location	string	Object-store URI where the table is materialized (s3://, gs://, az://, file://).
schema	object	Arrow schema for the table.
version	integer	Monotonic version number of the table state.
properties	object	Free-form key/value table properties (e.g. retention, owner, description).
indexes	array	Indexes attached to this table.
tags	array	Named tags pointing at specific versions of the table.
stats	object

View JSON Schema on GitHub

JSON Schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/lancedb/main/json-schema/lancedb-table-schema.json",
  "title": "LanceDB Table",
  "description": "A Lance table inside a LanceDB namespace. Tables are columnar (Lance format), versioned, and may carry vector, full-text, and scalar indexes.",
  "type": "object",
  "required": ["name", "namespace", "schema"],
  "properties": {
    "name": {
      "type": "string",
      "description": "Table identifier within its namespace.",
      "pattern": "^[A-Za-z_][A-Za-z0-9_]*$"
    },
    "namespace": {
      "type": "array",
      "description": "Hierarchical namespace path (e.g. ['warehouse', 'project']).",
      "items": { "type": "string" }
    },
    "location": {
      "type": "string",
      "format": "uri",
      "description": "Object-store URI where the table is materialized (s3://, gs://, az://, file://)."
    },
    "schema": {
      "type": "object",
      "description": "Arrow schema for the table.",
      "required": ["fields"],
      "properties": {
        "fields": {
          "type": "array",
          "items": { "$ref": "#/$defs/Field" }
        },
        "metadata": {
          "type": "object",
          "additionalProperties": { "type": "string" }
        }
      }
    },
    "version": {
      "type": "integer",
      "minimum": 0,
      "description": "Monotonic version number of the table state."
    },
    "properties": {
      "type": "object",
      "description": "Free-form key/value table properties (e.g. retention, owner, description).",
      "additionalProperties": { "type": "string" }
    },
    "indexes": {
      "type": "array",
      "description": "Indexes attached to this table.",
      "items": { "$ref": "#/$defs/Index" }
    },
    "tags": {
      "type": "array",
      "description": "Named tags pointing at specific versions of the table.",
      "items": { "$ref": "#/$defs/Tag" }
    },
    "stats": {
      "type": "object",
      "properties": {
        "numRows": { "type": "integer", "minimum": 0 },
        "numFragments": { "type": "integer", "minimum": 0 },
        "sizeBytes": { "type": "integer", "minimum": 0 }
      }
    }
  },
  "$defs": {
    "Field": {
      "type": "object",
      "required": ["name", "type"],
      "properties": {
        "name": { "type": "string" },
        "type": {
          "description": "Arrow logical type identifier (e.g. utf8, int64, float32, fixed_size_list).",
          "type": "string"
        },
        "nullable": { "type": "boolean", "default": true },
        "metadata": {
          "type": "object",
          "additionalProperties": { "type": "string" }
        },
        "vectorDimension": {
          "type": "integer",
          "minimum": 1,
          "description": "When the field is a fixed-size embedding vector, its dimensionality."
        }
      }
    },
    "Index": {
      "type": "object",
      "required": ["name", "column", "indexType"],
      "properties": {
        "name": { "type": "string" },
        "column": { "type": "string" },
        "indexType": {
          "type": "string",
          "enum": [
            "BTREE", "BITMAP", "LABEL_LIST", "FTS",
            "IVF_FLAT", "IVF_PQ", "IVF_HNSW_SQ", "IVF_HNSW_PQ"
          ]
        },
        "metric": {
          "type": "string",
          "enum": ["l2", "cosine", "dot"],
          "description": "Distance metric for vector indexes."
        },
        "numPartitions": { "type": "integer", "minimum": 1 },
        "numSubVectors": { "type": "integer", "minimum": 1 },
        "status": {
          "type": "string",
          "enum": ["PENDING", "BUILDING", "READY", "FAILED"]
        }
      }
    },
    "Tag": {
      "type": "object",
      "required": ["name", "version"],
      "properties": {
        "name": { "type": "string" },
        "version": { "type": "integer", "minimum": 0 }
      }
    }
  }
}