Module pyracmon.sql

This module provides the type for query generation from a template string containing unified marker.

"""
This module provides the type for query generation from a template string containing unified marker.
"""
from string import digits, Template
from typing import Any, Union
from .marker import Marker


class Sql:
    """
    Provides functionalities to render SQL string from the template containing placeholder markers.

    SQL rendering is conform to the way of `string.Template` which replaces `$` prefixed variables with parameters.
    """
    class Substitute:
        def __init__(self, marker: Marker):
            self.marker = marker

        def __getitem__(self, key):
            if key == "_":
                return self.marker()
            elif key[0] == "_" and all([c in digits for c in key[1:]]):
                return self.marker(int(key[1:]))
            else:
                return self.marker(key)

    def __init__(self, marker: Marker, template: str) -> None:
        #: Marker used in the template
        self.marker = marker
        #: SQL template.
        self.template = template

    def render(self, *args: Any, **kwargs: Any) -> tuple[str, Union[list[Any], dict[str, Any]]]:
        """
        Renders SQL and converts parameters into the form available for current database driver.

        Arguments type should be consistent to marker paramstyle, otherwise exception is raised.

        Args:
            args: Positional parameters.
            kwargs: Keyed parameters.
        Returns:
            SQL and parameters available in it.
        """
        self.marker.reset()

        sub = Sql.Substitute(self.marker)

        return Template(self.template).substitute(sub), self.marker.params(*args, **kwargs) # type: ignore

Classes

class Sql (marker: Marker, template: str)

Provides functionalities to render SQL string from the template containing placeholder markers.

SQL rendering is conform to the way of string.Template which replaces $ prefixed variables with parameters.

Expand source code

class Sql:
    """
    Provides functionalities to render SQL string from the template containing placeholder markers.

    SQL rendering is conform to the way of `string.Template` which replaces `$` prefixed variables with parameters.
    """
    class Substitute:
        def __init__(self, marker: Marker):
            self.marker = marker

        def __getitem__(self, key):
            if key == "_":
                return self.marker()
            elif key[0] == "_" and all([c in digits for c in key[1:]]):
                return self.marker(int(key[1:]))
            else:
                return self.marker(key)

    def __init__(self, marker: Marker, template: str) -> None:
        #: Marker used in the template
        self.marker = marker
        #: SQL template.
        self.template = template

    def render(self, *args: Any, **kwargs: Any) -> tuple[str, Union[list[Any], dict[str, Any]]]:
        """
        Renders SQL and converts parameters into the form available for current database driver.

        Arguments type should be consistent to marker paramstyle, otherwise exception is raised.

        Args:
            args: Positional parameters.
            kwargs: Keyed parameters.
        Returns:
            SQL and parameters available in it.
        """
        self.marker.reset()

        sub = Sql.Substitute(self.marker)

        return Template(self.template).substitute(sub), self.marker.params(*args, **kwargs) # type: ignore

Class variables

var Substitute

Instance variables

var marker

Marker used in the template

var template

SQL template.

Methods

def render(self, *args: Any, **kwargs: Any) ‑> tuple[str, typing.Union[list[typing.Any], dict[str, typing.Any]]]

Renders SQL and converts parameters into the form available for current database driver.

Arguments type should be consistent to marker paramstyle, otherwise exception is raised.

Args

args

Positional parameters.

kwargs

Keyed parameters.

Returns

SQL and parameters available in it.

Expand source code

def render(self, *args: Any, **kwargs: Any) -> tuple[str, Union[list[Any], dict[str, Any]]]:
    """
    Renders SQL and converts parameters into the form available for current database driver.

    Arguments type should be consistent to marker paramstyle, otherwise exception is raised.

    Args:
        args: Positional parameters.
        kwargs: Keyed parameters.
    Returns:
        SQL and parameters available in it.
    """
    self.marker.reset()

    sub = Sql.Substitute(self.marker)

    return Template(self.template).substitute(sub), self.marker.params(*args, **kwargs) # type: ignore