114 lines
3.0 KiB
Python
114 lines
3.0 KiB
Python
from .connection import _replace_char
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from .conditions import Condition
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class _updateField:
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__slots__ = ()
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_EMPTY = object() # Return value for `value` indicating no value should be added
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def key_field(self, key):
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raise NotImplementedError
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def value_field(self, key):
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raise NotImplementedError
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class UpdateValue(_updateField):
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__slots__ = ('key_str', 'value')
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def __init__(self, key_str, value=_updateField._EMPTY):
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self.key_str = key_str
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self.value = value
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def key_field(self, key):
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return self.key_str.format(key=key, value=_replace_char, replace=_replace_char)
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def value_field(self, key):
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return self.value
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class UpdateValueAdd(_updateField):
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__slots__ = ('value',)
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def __init__(self, value):
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self.value = value
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def key_field(self, key):
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return "{key} = {key} + {replace}".format(key=key, replace=_replace_char)
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def value_field(self, key):
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return self.value
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def _format_conditions(conditions):
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"""
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Formats a dictionary of conditions into a string suitable for 'WHERE' clauses.
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Supports `IN` type conditionals.
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"""
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if not conditions:
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return ("", tuple())
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values = []
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conditional_strings = []
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for key, item in conditions.items():
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if isinstance(item, (list, tuple)):
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conditional_strings.append("{} IN ({})".format(key, ", ".join([_replace_char] * len(item))))
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values.extend(item)
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elif isinstance(item, Condition):
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item.apply(key, values, conditional_strings)
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else:
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conditional_strings.append("{}={}".format(key, _replace_char))
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values.append(item)
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return (' AND '.join(conditional_strings), values)
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def _format_selectkeys(keys):
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"""
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Formats a list of keys into a string suitable for `SELECT`.
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"""
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if not keys:
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return "*"
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else:
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return ", ".join(keys)
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def _format_insertkeys(keys):
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"""
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Formats a list of keys into a string suitable for `INSERT`
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"""
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if not keys:
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return ""
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else:
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return "({})".format(", ".join(keys))
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def _format_insertvalues(values):
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"""
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Formats a list of values into a string suitable for `INSERT`
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"""
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value_str = "({})".format(", ".join(_replace_char for value in values))
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return (value_str, values)
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def _format_updatestr(valuedict):
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"""
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Formats a dictionary of keys and values into a string suitable for 'SET' clauses.
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"""
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if not valuedict:
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return ("", tuple())
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key_fields = []
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values = []
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for key, value in valuedict.items():
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if isinstance(value, _updateField):
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key_fields.append(value.key_field(key))
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v = value.value_field(key)
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if v is not _updateField._EMPTY:
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values.append(value.value_field(key))
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else:
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key_fields.append("{} = {}".format(key, _replace_char))
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values.append(value)
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return (', '.join(key_fields), values)
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