Validating Data

ZSchema can validate whether records confirm was a defined schema.

In a simple example:

r = Record({
	"field":String(),
})

# executes successfully
r.validate({"field":"hello world"})

# raise DataValidationException
r.validate({"field":False})

Validation Policies

Fields and types can specify one of several different validation poilcies (similar to how other field/type attributes are defined) by passing in one of the following values to validation_policy:

• error: raises DataValidationException the first time a validation error occurs. This is the default for the root record.

• warn: calls logging.warn on every validation error.

• ignore: does nothing on an a validation error

• inherit: uses the field's parent's validation level. This is the default for all types except the root record.

By default all types use the validation policy inherit, except for Record, which uses the default error. This means that without any additional confirmation, calling .validate with a record that doesn't conform will lead to a DataValidationException exception.

You can also define more complex validation patterns. For example:

Child = SubRecordType({
	"myField":String()
})

record = Record({
	"willError":Child(validation_policy="error"),
	"willWarn":Child(validation_policy="warn"),
	"willIgnore":Child(validation_policy="ignore"),
	# These two cases are identical, because by default types inherit
	"willInherit":Child(),
	"willInheritExplicitly":Child(validation_policy="inherit"),
})

When validating without any explicit policy specified, the record's policy will be used. For example:

# no errors
record.validate({"willIgnore":"garbage"})

# warnings provided
record.validate({"WillWarn":"garbage", "willIgnore":"garbage"})

# both will raise exceptions
record.validate({"willError":"garbage"})
record.validate({"willInherit":"garbage"})

However, it's possible to override as well, by specifiying a policy when calling validate:

# DataValidationException will be raised: 
record.validate({"willIgnore":"garbage"}, policy="error")