BigQuery DDL

Overview

The BigQuery DDL generator produces native Google BigQuery CREATE TABLE statements from a LinkML schema. It extends the SQL DDL generator with BigQuery-specific types (ARRAY<T>, STRUCT<...>, TIMESTAMP) and supports BigQuery table options such as time/range partitioning, clustering, and table descriptions via LinkML annotations.

Note

This generator requires the sqlalchemy-bigquery optional dependency. Install it with: pip install 'linkml[bigquery]'

Example Output

Given a schema with a Person class, the generator produces DDL like:

CREATE TABLE `Person` (
  id STRING NOT NULL,
  name STRING,
  age INT64,
  aliases ARRAY<STRING>
);

BigQuery Annotations

You can control BigQuery-specific table options via slot/class annotations:

• bigquery_type — override the column type (e.g. TIMESTAMP)

• bigquery_partition_by — field name to use for time/range partitioning

• bigquery_partition_type — DAY, HOUR, MONTH, YEAR, or RANGE

• bigquery_cluster_by — comma-separated field names for clustering

• bigquery_description — table-level description string

Docs

Command Line

gen-bigquery

Generate BigQuery DDL representation

gen-bigquery [OPTIONS] YAMLFILE

Options

--dataset <dataset>

BigQuery dataset prefix

-V, --version

Show the version and exit.

-f, --format <format>

Output format

Default:

'bigquery'

Options:

bigquery

--metadata, --no-metadata

Include metadata in output

Default:

True

--useuris, --metauris

Use class and slot URIs over model uris

Default:

True

-im, --importmap <importmap>

Import mapping file

--log_level <log_level>

Logging level

Default:

'WARNING'

Options:

CRITICAL | ERROR | WARNING | INFO | DEBUG

-v, --verbose

Verbosity. Takes precedence over –log_level.

--mergeimports, --no-mergeimports

Merge imports into source file (default=mergeimports)

--stacktrace, --no-stacktrace

Print a stack trace when an error occurs

Default:

False

Arguments

YAMLFILE

Required argument

Code

class linkml.generators.bigquerygen.BigQueryGenerator(schema: str | ~typing.TextIO | ~linkml_runtime.linkml_model.meta.SchemaDefinition | Generator | ~pathlib.Path, schemaview: ~linkml_runtime.utils.schemaview.SchemaView | None = None, format: str | None = None, metadata: bool = True, useuris: bool | None = None, log_level: int | None = 30, mergeimports: bool | None = True, source_file_date: str | None = None, source_file_size: int | None = None, logger: ~logging.Logger | None = None, verbose: bool | None = None, output: str | None = None, namespaces: ~linkml_runtime.utils.namespaces.Namespaces | None = None, directory_output: bool = False, base_dir: str = None, metamodel_name_map: dict[str, str] = None, importmap: str | ~collections.abc.Mapping[str, str] | None = None, emit_prefixes: set[str] = <factory>, metamodel: ~linkml.utils.schemaloader.SchemaLoader = None, stacktrace: bool = False, include: str | ~pathlib.Path | ~linkml_runtime.linkml_model.meta.SchemaDefinition | None = None, use_inherits: bool = False, dialect: str = 'sqlite', inject_primary_keys: bool = False, use_foreign_keys: bool = False, rename_foreign_keys: bool = False, direct_mapping: bool = False, relative_slot_num: bool = False, default_length_oracle: int = 4096, generate_abstract_class_ddl: bool = True, autogenerate_index: bool = True, dataset: str | None = None)

A Generator for BigQuery CREATE TABLE DDL.

Produces native BigQuery DDL including ARRAY<T>, STRUCT<…>, PARTITION BY, CLUSTER BY, and OPTIONS clauses.

Usage:

gen = BigQueryGenerator("schema.yaml")
print(gen.serialize())

generate_ddl(**kwargs) → str

Generate BigQuery CREATE TABLE DDL for all non-abstract, non-mixin classes.

serialize(**kwargs) → str

Generate output in the required format

Parameters:

kwargs – Generator specific parameters

Returns:

Generated output