Python django.db.models.aggregates.StdDev() Examples

The following are 12 code examples of django.db.models.aggregates.StdDev(). You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may also want to check out all available functions/classes of the module django.db.models.aggregates , or try the search function .
Example #1
Source File: operations.py    From python with Apache License 2.0 6 votes vote down vote up 
def check_expression_support(self, expression):
        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
        bad_aggregates = (aggregates.Sum, aggregates.Avg, aggregates.Variance, aggregates.StdDev)
        if isinstance(expression, bad_aggregates):
            for expr in expression.get_source_expressions():
                try:
                    output_field = expr.output_field
                    if isinstance(output_field, bad_fields):
                        raise NotImplementedError(
                            'You cannot use Sum, Avg, StdDev, and Variance '
                            'aggregations on date/time fields in sqlite3 '
                            'since date/time is saved as text.'
                        )
                except FieldError:
                    # Not every subexpression has an output_field which is fine
                    # to ignore.
                    pass
Example #2
Source File: operations.py    From openhgsenti with Apache License 2.0 6 votes vote down vote up 
def check_expression_support(self, expression):
        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
        bad_aggregates = (aggregates.Sum, aggregates.Avg, aggregates.Variance, aggregates.StdDev)
        if isinstance(expression, bad_aggregates):
            for expr in expression.get_source_expressions():
                try:
                    output_field = expr.output_field
                    if isinstance(output_field, bad_fields):
                        raise NotImplementedError(
                            'You cannot use Sum, Avg, StdDev, and Variance '
                            'aggregations on date/time fields in sqlite3 '
                            'since date/time is saved as text.'
                        )
                except FieldError:
                    # Not every subexpression has an output_field which is fine
                    # to ignore.
                    pass
Example #3
Source File: operations.py    From python2017 with MIT License 6 votes vote down vote up 
def check_expression_support(self, expression):
        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
        bad_aggregates = (aggregates.Sum, aggregates.Avg, aggregates.Variance, aggregates.StdDev)
        if isinstance(expression, bad_aggregates):
            for expr in expression.get_source_expressions():
                try:
                    output_field = expr.output_field
                    if isinstance(output_field, bad_fields):
                        raise NotImplementedError(
                            'You cannot use Sum, Avg, StdDev, and Variance '
                            'aggregations on date/time fields in sqlite3 '
                            'since date/time is saved as text.'
                        )
                except FieldError:
                    # Not every subexpression has an output_field which is fine
                    # to ignore.
                    pass
Example #4
Source File: features.py    From GTDWeb with GNU General Public License v2.0 5 votes vote down vote up 
def supports_stddev(self):
        """Confirm support for STDDEV and related stats functions."""
        try:
            self.connection.ops.check_expression_support(StdDev(1))
            return True
        except NotImplementedError:
            return False
Example #5
Source File: operations.py    From GTDWeb with GNU General Public License v2.0 5 votes vote down vote up 
def check_expression_support(self, expression):
        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
        bad_aggregates = (aggregates.Sum, aggregates.Avg, aggregates.Variance, aggregates.StdDev)
        if isinstance(expression, bad_aggregates):
            try:
                output_field = expression.input_field.output_field
                if isinstance(output_field, bad_fields):
                    raise NotImplementedError(
                        'You cannot use Sum, Avg, StdDev and Variance aggregations '
                        'on date/time fields in sqlite3 '
                        'since date/time is saved as text.')
            except FieldError:
                # not every sub-expression has an output_field which is fine to
                # ignore
                pass
Example #6
Source File: features.py    From bioforum with MIT License 5 votes vote down vote up 
def supports_stddev(self):
        """Confirm support for STDDEV and related stats functions."""
        try:
            self.connection.ops.check_expression_support(StdDev(1))
            return True
        except NotImplementedError:
            return False
Example #7
Source File: operations.py    From bioforum with MIT License 5 votes vote down vote up 
def check_expression_support(self, expression):
        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
        bad_aggregates = (aggregates.Sum, aggregates.Avg, aggregates.Variance, aggregates.StdDev)
        if isinstance(expression, bad_aggregates):
            for expr in expression.get_source_expressions():
                try:
                    output_field = expr.output_field
                except FieldError:
                    # Not every subexpression has an output_field which is fine
                    # to ignore.
                    pass
                else:
                    if isinstance(output_field, bad_fields):
                        raise NotImplementedError(
                            'You cannot use Sum, Avg, StdDev, and Variance '
                            'aggregations on date/time fields in sqlite3 '
                            'since date/time is saved as text.'
                        )
Example #8
Source File: features.py    From Hands-On-Application-Development-with-PyCharm with MIT License 5 votes vote down vote up 
def supports_stddev(self):
        """Confirm support for STDDEV and related stats functions."""
        try:
            self.connection.ops.check_expression_support(StdDev(1))
        except NotSupportedError:
            return False
        return True
Example #9
Source File: operations.py    From Hands-On-Application-Development-with-PyCharm with MIT License 5 votes vote down vote up 
def check_expression_support(self, expression):
        bad_fields = (fields.DateField, fields.DateTimeField, fields.TimeField)
        bad_aggregates = (aggregates.Sum, aggregates.Avg, aggregates.Variance, aggregates.StdDev)
        if isinstance(expression, bad_aggregates):
            for expr in expression.get_source_expressions():
                try:
                    output_field = expr.output_field
                except FieldError:
                    # Not every subexpression has an output_field which is fine
                    # to ignore.
                    pass
                else:
                    if isinstance(output_field, bad_fields):
                        raise utils.NotSupportedError(
                            'You cannot use Sum, Avg, StdDev, and Variance '
                            'aggregations on date/time fields in sqlite3 '
                            'since date/time is saved as text.'
                        )
Example #10
Source File: features.py    From python with Apache License 2.0 5 votes vote down vote up 
def supports_stddev(self):
        """Confirm support for STDDEV and related stats functions."""
        try:
            self.connection.ops.check_expression_support(StdDev(1))
            return True
        except NotImplementedError:
            return False
Example #11
Source File: features.py    From openhgsenti with Apache License 2.0 5 votes vote down vote up 
def supports_stddev(self):
        """Confirm support for STDDEV and related stats functions."""
        try:
            self.connection.ops.check_expression_support(StdDev(1))
            return True
        except NotImplementedError:
            return False
Example #12
Source File: features.py    From python2017 with MIT License 5 votes vote down vote up 
def supports_stddev(self):
        """Confirm support for STDDEV and related stats functions."""
        try:
            self.connection.ops.check_expression_support(StdDev(1))
            return True
        except NotImplementedError:
            return False