sqlglot.optimizer.optimizer API documentation

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# sqlglot.optimizer.optimizer

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     1from __future__ import annotations
     2
     3import typing as t
     4
     5import sqlglot
     6from sqlglot import Schema, exp
     7from sqlglot.dialects.dialect import DialectType
     8from sqlglot.optimizer.annotate_types import annotate_types
     9from sqlglot.optimizer.canonicalize import canonicalize
    10from sqlglot.optimizer.eliminate_ctes import eliminate_ctes
    11from sqlglot.optimizer.eliminate_joins import eliminate_joins
    12from sqlglot.optimizer.eliminate_subqueries import eliminate_subqueries
    13from sqlglot.optimizer.isolate_table_selects import isolate_table_selects
    14from sqlglot.optimizer.lower_identities import lower_identities
    15from sqlglot.optimizer.merge_subqueries import merge_subqueries
    16from sqlglot.optimizer.normalize import normalize
    17from sqlglot.optimizer.optimize_joins import optimize_joins
    18from sqlglot.optimizer.pushdown_predicates import pushdown_predicates
    19from sqlglot.optimizer.pushdown_projections import pushdown_projections
    20from sqlglot.optimizer.qualify_columns import qualify_columns, validate_qualify_columns
    21from sqlglot.optimizer.qualify_tables import qualify_tables
    22from sqlglot.optimizer.simplify import simplify
    23from sqlglot.optimizer.unnest_subqueries import unnest_subqueries
    24from sqlglot.schema import ensure_schema
    25
    26RULES = (
    27    lower_identities,
    28    qualify_tables,
    29    isolate_table_selects,
    30    qualify_columns,
    31    pushdown_projections,
    32    validate_qualify_columns,
    33    normalize,
    34    unnest_subqueries,
    35    pushdown_predicates,
    36    optimize_joins,
    37    eliminate_subqueries,
    38    merge_subqueries,
    39    eliminate_joins,
    40    eliminate_ctes,
    41    annotate_types,
    42    canonicalize,
    43    simplify,
    44)
    45
    46
    47def optimize(
    48    expression: str | exp.Expression,
    49    schema: t.Optional[dict | Schema] = None,
    50    db: t.Optional[str] = None,
    51    catalog: t.Optional[str] = None,
    52    dialect: DialectType = None,
    53    rules: t.Sequence[t.Callable] = RULES,
    54    **kwargs,
    55):
    56    """
    57    Rewrite a sqlglot AST into an optimized form.
    58
    59    Args:
    60        expression: expression to optimize
    61        schema: database schema.
    62            This can either be an instance of `sqlglot.optimizer.Schema` or a mapping in one of
    63            the following forms:
    64                1. {table: {col: type}}
    65                2. {db: {table: {col: type}}}
    66                3. {catalog: {db: {table: {col: type}}}}
    67            If no schema is provided then the default schema defined at `sqlgot.schema` will be used
    68        db: specify the default database, as might be set by a `USE DATABASE db` statement
    69        catalog: specify the default catalog, as might be set by a `USE CATALOG c` statement
    70        dialect: The dialect to parse the sql string.
    71        rules: sequence of optimizer rules to use.
    72            Many of the rules require tables and columns to be qualified.
    73            Do not remove qualify_tables or qualify_columns from the sequence of rules unless you know
    74            what you're doing!
    75        **kwargs: If a rule has a keyword argument with a same name in **kwargs, it will be passed in.
    76    Returns:
    77        sqlglot.Expression: optimized expression
    78    """
    79    schema = ensure_schema(schema or sqlglot.schema, dialect=dialect)
    80    possible_kwargs = {"db": db, "catalog": catalog, "schema": schema, **kwargs}
    81    expression = exp.maybe_parse(expression, dialect=dialect, copy=True)
    82
    83    for rule in rules:
    84        # Find any additional rule parameters, beyond `expression`
    85        rule_params = rule.__code__.co_varnames
    86        rule_kwargs = {
    87            param: possible_kwargs[param] for param in rule_params if param in possible_kwargs
    88        }
    89        expression = rule(expression, **rule_kwargs)
    90
    91    return expression

def optimize( expression: str | sqlglot.expressions.Expression, schema: Union[dict, sqlglot.schema.Schema, NoneType] = None, db: Optional[str] = None, catalog: Optional[str] = None, dialect: Union[str, sqlglot.dialects.dialect.Dialect, Type[sqlglot.dialects.dialect.Dialect], NoneType] = None, rules: Sequence[Callable] = (<function lower_identities at 0x7f0af2fc76d0>, <function qualify_tables at 0x7f0af2fa1d80>, <function isolate_table_selects at 0x7f0af2fc7370>, <function qualify_columns at 0x7f0af2fa0c10>, <function pushdown_projections at 0x7f0af2fa1750>, <function validate_qualify_columns at 0x7f0af2fa0ca0>, <function normalize at 0x7f0af2fc5630>, <function unnest_subqueries at 0x7f0af2fa1e10>, <function pushdown_predicates at 0x7f0af2fa0700>, <function optimize_joins at 0x7f0af2fa03a0>, <function eliminate_subqueries at 0x7f0af2fc72e0>, <function merge_subqueries at 0x7f0af2fc79a0>, <function eliminate_joins at 0x7f0af2fc53f0>, <function eliminate_ctes at 0x7f0af2fc52d0>, <function annotate_types at 0x7f0af2ff9a20>, <function canonicalize at 0x7f0af2fc4d30>, <function simplify at 0x7f0af2fc57e0>), **kwargs): View Source

    48def optimize(
    49    expression: str | exp.Expression,
    50    schema: t.Optional[dict | Schema] = None,
    51    db: t.Optional[str] = None,
    52    catalog: t.Optional[str] = None,
    53    dialect: DialectType = None,
    54    rules: t.Sequence[t.Callable] = RULES,
    55    **kwargs,
    56):
    57    """
    58    Rewrite a sqlglot AST into an optimized form.
    59
    60    Args:
    61        expression: expression to optimize
    62        schema: database schema.
    63            This can either be an instance of `sqlglot.optimizer.Schema` or a mapping in one of
    64            the following forms:
    65                1. {table: {col: type}}
    66                2. {db: {table: {col: type}}}
    67                3. {catalog: {db: {table: {col: type}}}}
    68            If no schema is provided then the default schema defined at `sqlgot.schema` will be used
    69        db: specify the default database, as might be set by a `USE DATABASE db` statement
    70        catalog: specify the default catalog, as might be set by a `USE CATALOG c` statement
    71        dialect: The dialect to parse the sql string.
    72        rules: sequence of optimizer rules to use.
    73            Many of the rules require tables and columns to be qualified.
    74            Do not remove qualify_tables or qualify_columns from the sequence of rules unless you know
    75            what you're doing!
    76        **kwargs: If a rule has a keyword argument with a same name in **kwargs, it will be passed in.
    77    Returns:
    78        sqlglot.Expression: optimized expression
    79    """
    80    schema = ensure_schema(schema or sqlglot.schema, dialect=dialect)
    81    possible_kwargs = {"db": db, "catalog": catalog, "schema": schema, **kwargs}
    82    expression = exp.maybe_parse(expression, dialect=dialect, copy=True)
    83
    84    for rule in rules:
    85        # Find any additional rule parameters, beyond `expression`
    86        rule_params = rule.__code__.co_varnames
    87        rule_kwargs = {
    88            param: possible_kwargs[param] for param in rule_params if param in possible_kwargs
    89        }
    90        expression = rule(expression, **rule_kwargs)
    91
    92    return expression

Rewrite a sqlglot AST into an optimized form.

###### Arguments:

- expression: expression to optimize
- schema: database schema. This can either be an instance of `sqlglot.optimizer.Schema` or a mapping in one of the following forms: 1. {table: {col: type}} 2. {db: {table: {col: type}}} 3. {catalog: {db: {table: {col: type}}}} If no schema is provided then the default schema defined at `sqlgot.schema` will be used
- db: specify the default database, as might be set by a `USE DATABASE db` statement
- catalog: specify the default catalog, as might be set by a `USE CATALOG c` statement
- dialect: The dialect to parse the sql string.
- rules: sequence of optimizer rules to use. Many of the rules require tables and columns to be qualified. Do not remove qualify_tables or qualify_columns from the sequence of rules unless you know what you're doing!
- *kwargs: If a rule has a keyword argument with a same name in *kwargs, it will be passed in.

###### Returns:

> sqlglot.Expression: optimized expression