Validating an Instance in Biztalk

How can one validate an instance of the input file and ensure that the required fields needed for business process are present, data type is correct and min/max lengths are conformed with. This is done to filter “junk” data going into Business Database and to maintain Database Integrity. Further if one needs to catch the errors and populate a database it becomes even more complicated. So what can be done?

Biztalk 2004 has no ability to validate instance on the fly and accumulate errors at once. But, Dot Net offers “SchemaValidation” class to validate the input instance and errors that are trapped can be accumulated and passed as a string through a stored procedure to a SQL/Oracle database. This is how it works.

1. Pass “Instance” and the “Schema” to the schema validation class.
a. Instance is the sample XML message that is to be validated.
b. Schema is the xsd schema that will contain all the information about the required fields, data types, lengths etc.

2. Creating the “tight” schema is a tedious process especially if the file is long. Each field has to be selected and the properties set.

a. For required fields.

i. String type: Set following properties in schema

1. Base Data Type : string
2. Derived by: Restriction
3. Nillable : False
4. Min Occurs: 1 (empty is 1 too)
5. Max length = as required
6. Min length = 1
ii. Date type:

1. Base Data Type : Date
2. Derived by: Restriction
3. Nillable : False
4. Min Occurs: 1 (empty is 1 too)

iii. Integer type

1. Base Data Type : Integer
2. Derived by: Restriction
3. Nillable : False
4. Min Occurs: 1 (empty is 1 too)
5. Max Facet value = as required
6. Min Facet value = as required

b. For optional fields

i. String:

1. Base Data Type : string
2. Derived by: Restriction
3. Nillable : True
4. Min Occurs: 0 (empty is 1 too)
5. Max length = as required
6. Min length = 0

ii. Date Type:

1. Base Data Type : date
2. Derived by: List
3. Nillable : True
4. Min Occurs: 1 (empty is 1 too)

iii. Integer type

1. Base Data Type : Integer
2. Derived by: List
3. Nillable : True
4. Min Occurs: 1 (empty is 1 too)

Note: Decimal Types follow same rules as Integer types. It is not possible to control the lengths for Decimal and Integer OPTIONAL fields from Biztalk schemas. To do this use .Net class that can read the length and validate it in next stage and reject or accept depending on the results.

3. After this “tight” schema is created put this in a folder. Do NOT forget to append a namespace to this schema before passing it in the .Net class. The .Net Class will not work without namespace.