def checkType(self, meta_attribute_definition:dict, meta_attribute_key:str, value:str, primary_key_value:str):
# field type check
is_valid_type = True
if (MetaUtils.exists(meta_attribute_definition, "Type")):
# if a default value has been specified then ignore the type check if the value matches the default
if (MetaUtils.exists(meta_attribute_definition, "Default")):
if (value==meta_attribute_definition["Default"]):
is_valid_type = False
if (meta_attribute_definition["Type"] in ["int","integer"]):
if ( (MetaUtils.isBlankOrNull(value)) or (not MetaUtils.isInt(value)) ):
if (not MetaUtils.isAllowBlank(meta_attribute_definition)):
self.addDataQualityError(DataQualityError(meta_attribute_key,error_dimension=DataQualityDimension.METADATACOMPLIANCE.value, description="Error: Value '" + value + "' is not an int. An int was expected",primary_key_value=primary_key_value))
is_valid_type = False
elif (meta_attribute_definition["Type"] in ["float","number"]):
if ( (MetaUtils.isBlankOrNull(value)) or (not MetaUtils.isFloat(value)) ):
if (not MetaUtils.isAllowBlank(meta_attribute_definition)):
self.addDataQualityError(DataQualityError(meta_attribute_key,error_dimension=DataQualityDimension.METADATACOMPLIANCE.value, description="Error: Value '" + value + "' is not a float. A float was expected",primary_key_value=primary_key_value))
is_valid_type = False
elif (meta_attribute_definition["Type"] in ["bool","boolean"]):
if ( (MetaUtils.isBlankOrNull(value)) or (not value.lower() in ["false", "true", "f", "t", "n", "y", "no", "yes", "0", "1"]) ):
if (not MetaUtils.isAllowBlank(meta_attribute_definition)):
self.addDataQualityError(DataQualityError(meta_attribute_key,error_dimension=DataQualityDimension.METADATACOMPLIANCE.value, description="Error: Value '" + value + "' is not a boolean. A boolean was expected",primary_key_value=primary_key_value))
is_valid_type = False
# given that min and max checks only apply to int and float values we may as well test for them now
if (is_valid_type):
self.checkMinMax(meta_attribute_definition, meta_attribute_key, value, primary_key_value)
def checkMandatory(self, meta_attribute_definition: dict,
meta_attribute_key: str, value: str,
primary_key_value: str):
# mandatory field check
if (MetaUtils.isTrue(meta_attribute_definition, "Mandatory")):
if ((MetaUtils.isBlankOrNull(value)) and
(not MetaUtils.isAllowBlank(meta_attribute_definition))):
self.addDataQualityError(
DataQualityError(
meta_attribute_key,
error_dimension=DataQualityDimension.
COMPLETENESSMANDATORY.value,
description=
"Error: Mandatory field is BLANK or NULL. A value is required.",
primary_key_value=primary_key_value))
else:
# optional field check. According to LANG optional fields shpuld contain some sort of default value
# i.e. no field shpould ever be blank or NULL.
if ((MetaUtils.isBlankOrNull(value)) and
(not MetaUtils.isAllowBlank(meta_attribute_definition))):
self.addDataQualityError(
DataQualityError(
meta_attribute_key,
error_dimension=DataQualityDimension.
COMPLETENESSOPTIONAL.value,
description=
"Error: Optional field is BLANK or NULL. A default value is required.",
primary_key_value=primary_key_value))
def evaluateExpression(self, meta_attribute_definition: dict,
meta_attribute_key: str):
# evaluate any custom expressions
if (MetaUtils.exists(meta_attribute_definition, "Expression")):
expr = meta_attribute_definition["Expression"]
# %1 is a placeholder for whatever the column name is owning the expression (it's just a shortcut)
expr = expr.replace("%1", "[" + meta_attribute_key + "]")
exp = ExpressionBuilder()
fields = exp.parseExpr(expr)
colData = dict()
# grab all of the columns that we need and store in a local dict
for field in fields:
# grab the column data out of the resultset
values = SQLTools.getCol(self.dataset, field)
# if the column couldn't be found then we have a configuration issue so raise an exception
if (values is None):
raise ValidationError(
"Error evaluating expression: '" + expr +
"'. Unable to find column '" + field +
"' in the resultset", None)
colData.update(values)
# convert the seperate columns into an array of name,value pairs
pairs = [dict(zip(colData, col)) for col in zip(*colData.values())]
for pair in pairs:
result = None
ev = exp.merge(expr, pair)
try:
result = eval(ev)
except Exception as e:
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
BUSINESSRULECOMPLIANCE.value,
description="Error: Expression '" +
ev + "' returned an error '" +
str(e) + "'"))
result = None
if ((not result is None) and (result == False)):
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
BUSINESSRULECOMPLIANCE.value,
description="Error: Expression '" +
ev + "' returned FALSE"))
def checkMinMax(self, meta_attribute_definition: dict,
meta_attribute_key: str, value: str,
primary_key_value: str):
# field value range check (int and float only although in theory we could specify min and max ranges for other attributes)
min = -1
max = -1
val = -1
default = -1
if (MetaUtils.exists(meta_attribute_definition, "Min")):
try:
min = float(meta_attribute_definition["Min"])
except Exception as e:
pass
if (MetaUtils.exists(meta_attribute_definition, "Max")):
try:
max = float(meta_attribute_definition["Max"])
except Exception as e:
pass
if (MetaUtils.exists(meta_attribute_definition, "Default")):
try:
default = float(meta_attribute_definition["Default"])
except Exception as e:
pass
try:
val = float(value)
except Exception as e:
pass
if (min != -1):
if (val != -1 and val < min and val != default):
# error
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
METADATACOMPLIANCE.value,
description="Error: Value '" + value +
"' must be >= " + str(min),
primary_key_value=primary_key_value))
if (max != -1):
if (val != -1 and val > max and val != default):
# error
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
METADATACOMPLIANCE.value,
description="Error: Value '" + value +
"' must be <= " + str(max),
primary_key_value=primary_key_value))
def checkComposite(self, meta_attribute_definition:dict, meta_attribute_key:str):
# unique field check
if (MetaUtils.exists(meta_attribute_definition, "Composite")):
# sum the number of times value appears in the row. this is faster than using list.count(value)
list_of_attribute_keys = meta_attribute_definition["Composite"]
attribute_keys = '+'.join(map(str, list_of_attribute_keys))
attribute_keys = attribute_keys.replace("%1", meta_attribute_key)
# populate a dictionary of just the values that are required to create the composite meta_attribute_key
attribute_data={}
for col in list_of_attribute_keys:
col = col.replace("%1", meta_attribute_key)
attribute_data[col]=SQLTools.getColValues(self.dataset, col)
seen=set()
rowindex=0
# convert the dictionary of columns into a list of tuples
fields=[dict(zip(attribute_data, col)) for col in zip(*attribute_data.values())]
# check to see if there is are any duplicates in the order of attribute_keys provided
for row in fields:
# join the values from the columns that make up the composite meta_attribute_key to form a single value
composite_key = '|'.join(map(str, row.values()))
if (composite_key in seen):
self.addDataQualityError(DataQualityError(meta_attribute_key,error_dimension=DataQualityDimension.UNIQUENESS.value, description="Error: Duplicate composite meta_attribute_key: '" + attribute_keys + "', values: '" + composite_key + "'", primary_key_value=composite_key))
else:
seen.add(composite_key)
def checkStartsWith(self, meta_attribute_definition: dict,
meta_attribute_key: str, value: str,
primary_key_value: str):
# enumerated field check
if (MetaUtils.exists(meta_attribute_definition, "StartsWith")):
# startsWith is expected to be a list
startsWith = meta_attribute_definition["StartsWith"]
# check that the value exists within the provided list. If the value is blank then ignore it
# as we should have picked it up in the mandatory/optional test anyway
# (i.e. if the field is optional but a value has been provided then we check it against the supplied list)
if ((len(value) > 0) and (value != "(Null)")):
found = False
for s in startsWith:
if value.startswith(s):
found = True
break
if (not found):
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
FORMATCONSISTENCY.value,
description="Error: Value '" + value +
"' does not begin with any of: '" +
str(startsWith) + "'",
primary_key_value=primary_key_value))
def checkEnum(self, meta_attribute_definition: dict,
meta_attribute_key: str, value: str, primary_key_value: str):
# enumerated field check
if (MetaUtils.exists(meta_attribute_definition, "Enum")):
# enum is expected to be a list
enum = meta_attribute_definition["Enum"]
if (MetaUtils.exists(meta_attribute_definition, "Default")):
if (value == meta_attribute_definition["Default"]):
# if trhe value equals the default then do nothing
return
# check that the value exists within the provided list. If the value is blank then ignore it
# as we should have picked it up in the mandatory/optional test anyway
# (i.e. if the field is optional but a value has been provided then we check it against the supplied list)
if ((len(value) > 0) and (value not in enum)
and (value != "(Null)")):
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
METADATACOMPLIANCE.value,
description="Error: Value '" + value +
"' is outside the enumeration set '" +
str(enum) + "'",
primary_key_value=primary_key_value))
def addDataQualityError(self: object,
data_quality_error: DataQualityError):
"""
Add a new dimension.
"""
if (data_quality_error is None):
raise ValidationError(
"LANG Exception: DataQualityError has not been set", None)
self.validation_errors.append(data_quality_error.to_dict())
def checkSize(self, meta_attribute_definition: dict,
meta_attribute_key: str, value: str, primary_key_value: str):
# field length check
if (MetaUtils.exists(meta_attribute_definition, "Size")):
if ((len(value) > int(meta_attribute_definition["Size"]))
and (not MetaUtils.isBlankOrNull(value))):
self.addDataQualityError(
DataQualityError(meta_attribute_key,
error_dimension=DataQualityDimension.
METADATACOMPLIANCE.value,
description="Error: Value '" + value +
"' is longer than size '" +
str(meta_attribute_definition["Size"]) +
"'",
primary_key_value=primary_key_value))
def validate(self:object, customValidator:str=None):
"""
Validate a resultset against predefined metadata based on the LANG rules of data quality.
"""
if (self.metadata is None):
raise ValidationError("LANG Exception: meta-data has not been set", None)
elif (self.dataset is None):
raise ValidationError("LANG Exception: resultset has not been set", None)
"""
Change request: find and output the primary key in the error report file if specified
"""
primary_key = ""
primary_key_values = None
for key, item in self.metadata.items():
if (MetaUtils.isTrue(item, "PrimaryKey")):
primary_key = key
primary_key_values = self.dataset[primary_key]
break
"""
Execute a series of validations against the supplied column of data and the metadata for the column.
Which validation is run is determined by entries in the metadata.
"""
for meta_attribute_key, meta_attribute_definition in self.metadata.items():
if (meta_attribute_key in self.dataset):
print("Validating attribute \t'" + meta_attribute_key + "'...", end='\r')
attribute = self.dataset[meta_attribute_key]
for row_count in range(len(attribute)):
value = attribute[row_count]
"""
If a primarykey tag has been found then output the value so that the user
has a reference to search for the record in the source system.
If there is no primary key attribute set then output the row count
"""
if (not primary_key_values is None):
primary_key_value = primary_key_values[row_count]
else:
primary_key_value = "Row: " + str(row_count+1)
self.checkMandatory(meta_attribute_definition, meta_attribute_key, value, primary_key_value)
self.checkSize(meta_attribute_definition, meta_attribute_key, value, primary_key_value)
self.checkType(meta_attribute_definition, meta_attribute_key, value, primary_key_value)
self.checkEnum(meta_attribute_definition, meta_attribute_key, value, primary_key_value)
self.checkStartsWith(meta_attribute_definition, meta_attribute_key, value, primary_key_value)
# format check (must provide a regex)
if (MetaUtils.exists(meta_attribute_definition, "Format")):
re.purge()
regex=re.compile(meta_attribute_definition["Format"])
for row_count in range(len(attribute)):
primary_key_value = primary_key_values[row_count]
value = attribute[row_count]
isMatch = (not regex.match(value) is None)
if ( (not isMatch) and (not MetaUtils.isAllowBlank(meta_attribute_definition)) ):
self.addDataQualityError(DataQualityError(meta_attribute_key,error_dimension=DataQualityDimension.FORMATCONSISTENCY.value, description="Error: Value '" + value + "' does not match regex #'" + meta_attribute_definition["Format"] + "'"))
# unique field check
if (MetaUtils.isTrue(meta_attribute_definition, "Unique") ):
# quick count the number of times values occurs in the column. Assumes possibly sorted so breaks the loop if >1 occurences to save time0
seen = set()
for row_count in range(len(attribute)):
primary_key_value = primary_key_values[row_count]
value = attribute[row_count]
if (not value in seen):
seen.add(value) #only process a value once
else:
self.addDataQualityError(DataQualityError(meta_attribute_key,error_dimension=DataQualityDimension.UNIQUENESS.value, description="Error: Value '" + value + "' is not UNIQUE. A unique value was expected."))
self.checkComposite(meta_attribute_definition, meta_attribute_key)
# expression evaluation is different to processing field specific validations as it could link in other columns from the resultset
self.evaluateExpression(meta_attribute_definition, meta_attribute_key)
print("Validating attribute \t'" + meta_attribute_key + "'...\t\t..Complete.")
else:
self.addDataQualityError(DataQualityError(meta_attribute_key, error_dimension=DataQualityDimension.METADATACOMPLIANCE.value, description="Error: Attribute '" + meta_attribute_key + "' was not found in the dataset."))
# only invoke the custom validator if one has been provoded
if (not customValidator is None and len(customValidator) > 0):
self.customValidator(customValidator)
