71 lines
3 KiB
Python
71 lines
3 KiB
Python
import sqlglot
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from sqlglot.optimizer.annotate_types import annotate_types
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from sqlglot.optimizer.canonicalize import canonicalize
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from sqlglot.optimizer.eliminate_ctes import eliminate_ctes
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from sqlglot.optimizer.eliminate_joins import eliminate_joins
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from sqlglot.optimizer.eliminate_subqueries import eliminate_subqueries
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from sqlglot.optimizer.expand_multi_table_selects import expand_multi_table_selects
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from sqlglot.optimizer.isolate_table_selects import isolate_table_selects
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from sqlglot.optimizer.lower_identities import lower_identities
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from sqlglot.optimizer.merge_subqueries import merge_subqueries
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from sqlglot.optimizer.normalize import normalize
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from sqlglot.optimizer.optimize_joins import optimize_joins
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from sqlglot.optimizer.pushdown_predicates import pushdown_predicates
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from sqlglot.optimizer.pushdown_projections import pushdown_projections
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from sqlglot.optimizer.qualify_columns import qualify_columns
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from sqlglot.optimizer.qualify_tables import qualify_tables
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from sqlglot.optimizer.quote_identities import quote_identities
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from sqlglot.optimizer.unnest_subqueries import unnest_subqueries
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RULES = (
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lower_identities,
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qualify_tables,
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isolate_table_selects,
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qualify_columns,
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pushdown_projections,
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normalize,
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unnest_subqueries,
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expand_multi_table_selects,
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pushdown_predicates,
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optimize_joins,
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eliminate_subqueries,
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merge_subqueries,
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eliminate_joins,
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eliminate_ctes,
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annotate_types,
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canonicalize,
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quote_identities,
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)
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def optimize(expression, schema=None, db=None, catalog=None, rules=RULES, **kwargs):
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"""
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Rewrite a sqlglot AST into an optimized form.
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Args:
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expression (sqlglot.Expression): expression to optimize
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schema (dict|sqlglot.optimizer.Schema): database schema.
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This can either be an instance of `sqlglot.optimizer.Schema` or a mapping in one of
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the following forms:
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1. {table: {col: type}}
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2. {db: {table: {col: type}}}
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3. {catalog: {db: {table: {col: type}}}}
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If no schema is provided then the default schema defined at `sqlgot.schema` will be used
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db (str): specify the default database, as might be set by a `USE DATABASE db` statement
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catalog (str): specify the default catalog, as might be set by a `USE CATALOG c` statement
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rules (list): sequence of optimizer rules to use
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**kwargs: If a rule has a keyword argument with a same name in **kwargs, it will be passed in.
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Returns:
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sqlglot.Expression: optimized expression
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"""
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possible_kwargs = {"db": db, "catalog": catalog, "schema": schema or sqlglot.schema, **kwargs}
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expression = expression.copy()
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for rule in rules:
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# Find any additional rule parameters, beyond `expression`
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rule_params = rule.__code__.co_varnames
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rule_kwargs = {
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param: possible_kwargs[param] for param in rule_params if param in possible_kwargs
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}
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expression = rule(expression, **rule_kwargs)
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return expression
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