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Refs #28643 -- Added Repeat database function.
Thanks Tim Graham and Nick Pope for reviews.
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@ -4,6 +4,7 @@ SQLite3 backend for the sqlite3 module in the standard library.
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import datetime
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import decimal
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import math
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import operator
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import re
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import warnings
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from sqlite3 import dbapi2 as Database
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@ -170,6 +171,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
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conn.create_function("django_format_dtdelta", 3, _sqlite_format_dtdelta)
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conn.create_function("django_power", 2, _sqlite_power)
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conn.create_function('LPAD', 3, _sqlite_lpad)
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conn.create_function('REPEAT', 2, operator.mul)
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conn.create_function('RPAD', 3, _sqlite_rpad)
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conn.execute('PRAGMA foreign_keys = ON')
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return conn
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@ -6,8 +6,8 @@ from .datetime import (
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TruncQuarter, TruncSecond, TruncTime, TruncWeek, TruncYear,
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)
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from .text import (
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Chr, Concat, ConcatPair, Left, Length, Lower, LPad, LTrim, Ord, Replace,
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Right, RPad, RTrim, StrIndex, Substr, Trim, Upper,
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Chr, Concat, ConcatPair, Left, Length, Lower, LPad, LTrim, Ord, Repeat,
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Replace, Right, RPad, RTrim, StrIndex, Substr, Trim, Upper,
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)
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from .window import (
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CumeDist, DenseRank, FirstValue, Lag, LastValue, Lead, NthValue, Ntile,
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@ -25,8 +25,8 @@ __all__ = [
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'TruncWeek', 'TruncYear',
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# text
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'Chr', 'Concat', 'ConcatPair', 'Left', 'Length', 'Lower', 'LPad', 'LTrim',
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'Ord', 'Replace', 'Right', 'RPad', 'RTrim', 'StrIndex', 'Substr', 'Trim',
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'Upper',
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'Ord', 'Repeat', 'Replace', 'Right', 'RPad', 'RTrim', 'StrIndex', 'Substr',
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'Trim', 'Upper',
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# window
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'CumeDist', 'DenseRank', 'FirstValue', 'Lag', 'LastValue', 'Lead',
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'NthValue', 'Ntile', 'PercentRank', 'Rank', 'RowNumber',
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@ -152,6 +152,20 @@ class Ord(Transform):
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return super().as_sql(compiler, connection, function='UNICODE', **extra_context)
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class Repeat(BytesToCharFieldConversionMixin, Func):
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function = 'REPEAT'
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def __init__(self, expression, number, **extra):
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if not hasattr(number, 'resolve_expression') and number < 0:
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raise ValueError("'number' must be greater or equal to 0.")
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super().__init__(expression, number, **extra)
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def as_oracle(self, compiler, connection, **extra_context):
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expression, number = self.source_expressions
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rpad = RPad(expression, Length(expression) * number, expression)
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return rpad.as_sql(compiler, connection, **extra_context)
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class Replace(Func):
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function = 'REPLACE'
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@ -855,6 +855,25 @@ Usage example::
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>>> print(author.name_code_point)
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77
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``Repeat``
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----------
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.. class:: Repeat(expression, number, **extra)
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.. versionadded:: 2.1
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Returns the value of the given text field or expression repeated ``number``
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times.
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Usage example::
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>>> from django.db.models.functions import Repeat
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>>> Author.objects.create(name='John', alias='j')
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>>> Author.objects.update(name=Repeat('name', 3))
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1
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>>> print(Author.objects.get(alias='j').name)
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JohnJohnJohn
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``Replace``
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-----------
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@ -210,6 +210,7 @@ Models
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:class:`~django.db.models.functions.LPad`,
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:class:`~django.db.models.functions.LTrim`,
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:class:`~django.db.models.functions.Ord`,
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:class:`~django.db.models.functions.Repeat`,
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:class:`~django.db.models.functions.Replace`,
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:class:`~django.db.models.functions.Right`,
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:class:`~django.db.models.functions.RPad`,
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24
tests/db_functions/test_repeat.py
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24
tests/db_functions/test_repeat.py
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@ -0,0 +1,24 @@
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from django.db.models import CharField, Value
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from django.db.models.functions import Length, Repeat
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from django.test import TestCase
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from .models import Author
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class RepeatTests(TestCase):
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def test_basic(self):
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Author.objects.create(name='John', alias='xyz')
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tests = (
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(Repeat('name', 0), ''),
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(Repeat('name', 2), 'JohnJohn'),
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(Repeat('name', Length('alias'), output_field=CharField()), 'JohnJohnJohn'),
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(Repeat(Value('x'), 3, output_field=CharField()), 'xxx'),
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)
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for function, repeated_text in tests:
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with self.subTest(function=function):
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authors = Author.objects.annotate(repeated_text=function)
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self.assertQuerysetEqual(authors, [repeated_text], lambda a: a.repeated_text, ordered=False)
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def test_negative_number(self):
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with self.assertRaisesMessage(ValueError, "'number' must be greater or equal to 0."):
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Repeat('name', -1)
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