Whatever means for setting dataset's schema, when it comes time to load XML into dataset following rules are used:

1) Elements with a certain name are mapped into dataset of same table name.

2) Attributes and scalar-valued sub-elements are mapped into columns of that table.

3) The schema of table is expanded as appropriate if columns are not already in dataset or if dataset does not already contain a table by same name.

When loading an XML schema into dataset, a table is created for each complex type in schema, and containment is expressed using primary/foreign key relationships. The key columns are automatically inserted into schema, and a Data relation is added for each pair of related tables.

Therefore, when loading data that resides in multiple tables from SQL server or any other database that supports XML, it is in some ways more expedient to use XML loading facilities rather than DataSet command. The former enables loading all data in one step, whereas latter requires a dataset command per table, and also involves setting up relationships between tables manually.

An XML DSIG may contain multiple reference elements in same document

DSIG signatures may contain either signed XML object contained in XML object, or detached from signed object or document. When signed XML object envelops signature, enveloped signature value itself is not included in signature calculation and validation computation. For this you use enveloped-signature transform, removing whole signature element in which it is contained from digest calculation.

Public key digital signatures that provide nonrepudiation, such as RSA, are computationally intensive operations; therefore, DSIG also allows shared-key authentication that provides authentication but nonrepudiation. Collision resistant hashing of signed content is also used to save computational requirements.

Generating DSIG signatures: 1. Identity resources to be signed. 2. Calculating digest value and composing reference elements for each resource. 3. Composing signed info element from all references. 4. Computing value of signature method over identity resources to be signed element by applying algorithms like DSA, RSA-SHA1, etc 5. Composing signature elements with signedInfo, signature value, identity key used to sign, and other optional objects like signature properties.

An XML DSIG may contain multiple reference elements in same document.