mirror of
https://github.com/simonw/sqlite-utils.git
synced 2026-07-23 09:24:31 +02:00
60 lines
2 KiB
Python
60 lines
2 KiB
Python
try:
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import pysqlite3 as sqlite3
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import pysqlite3.dbapi2
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OperationalError = pysqlite3.dbapi2.OperationalError
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except ImportError:
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import sqlite3
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OperationalError = sqlite3.OperationalError
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def suggest_column_types(records):
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all_column_types = {}
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for record in records:
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for key, value in record.items():
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all_column_types.setdefault(key, set()).add(type(value))
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column_types = {}
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for key, types in all_column_types.items():
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# Ignore null values if at least one other type present:
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if len(types) > 1:
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types.discard(None.__class__)
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if {None.__class__} == types:
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t = str
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elif len(types) == 1:
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t = list(types)[0]
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# But if it's a subclass of list / tuple / dict, use str
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# instead as we will be storing it as JSON in the table
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for superclass in (list, tuple, dict):
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if issubclass(t, superclass):
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t = str
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elif {int, bool}.issuperset(types):
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t = int
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elif {int, float, bool}.issuperset(types):
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t = float
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elif {bytes, str}.issuperset(types):
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t = bytes
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else:
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t = str
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column_types[key] = t
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return column_types
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def column_affinity(column_type):
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# Implementation of SQLite affinity rules from
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# https://www.sqlite.org/datatype3.html#determination_of_column_affinity
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assert isinstance(column_type, str)
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column_type = column_type.upper().strip()
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if column_type == "":
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return str # We differ from spec, which says it should be BLOB
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if "INT" in column_type:
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return int
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if "CHAR" in column_type or "CLOB" in column_type or "TEXT" in column_type:
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return str
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if "BLOB" in column_type:
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return bytes
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if "REAL" in column_type or "FLOA" in column_type or "DOUB" in column_type:
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return float
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# Default is 'NUMERIC', which we currently also treat as float
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return float
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