Difficult Schema Interview Preparation Guide

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A schema is a blueprint of an XML document that defines the elements, data types and nesting structure of the page.
An XML schema is a road map for the XML document similar to a Document Type Definition (DTD). Created by the World Wide Web Consortium (W3C), schemas describe the elements and map out the presentation and nesting of XML documents.
Essentially, the schema enables all applications to understand the flow of the page and validate the elements.

★ SQL Server limits identifiers of schema components to a maximum length of 1000 Unicode characters. Also, surrogate character pairs within identifiers are not supported.
★ SQL Server does not support restrictions from union types.
★ The values for minOccurs and maxOccurs attributes must fit into 4-byte integers. Schemas that do not conform are rejected by the server.
★ xsi:schemaLocation and xsi:noNamespaceSchemaLocation
★ SQL Server ignores these attributes if they are present in the XML instance data inserted into a column or variable of xml data type.
★ SQL Server rejects schemas that have an particle without children, unless the particle is defined with a minOccurs attribute value of zero.
★ Currently, SQL Server does not support . XML schemas that include this element are rejected by the server.
★ Currently, SQL Server does not support <xsd:key>, <xsd:keyref>, and <xsd:unique> constraints for enforcing uniqueness or establishing keys and key references. XML schemas that contain these elements cannot be registered.
★ The length, minLength, and maxLength facets are stored as a long type. This type is a 32-bit type. Therefore, the range of acceptable values for these values is 2^31.
★ SQL Server does not support the NOTATION type.
★ SQL Server does not support types derived from xs:QName that use an XML Schema restriction element and the union types with xs:QName as a member element.
★ Members cannot be added to an existing substitution group in an XML schema collection.
★ The canonical representation of a value cannot violate the pattern restriction for its type.
★ SQL Server does not support XML schemas with types that have pattern facets or enumerations that violate those facets.
★ In working with large XML schema collections, an out-of-memory condition might occur.
★ SQL Server rejects schemas in which the block or final attribute has repeated values such as "restriction restriction" and "extension extension". .

Schemas allow all applications to understand the rules and content of the page.
A schema is the blueprint of an XML document. Since XML works to move data, it is essential that the sender and the receiver of this data both understand the content.

You could write a DTD for an XML page and accomplish some of the same goals. However, because a schema is written in XML, there is no new syntax or rules to understand. If you can write a page in XML, you can write an XML schema.

SQL server can return XML document using FOR XML clause. XML documents can be added to SQL Server database and you can use the OPENXML clause to display the data from the document as a relational result set. SQL Server 2000 supports XPath queries.

1) Creation of XML fragments: This is done from the relational data using FOR XML to the select query.
2) Ability to shred xml data to be stored in the database.
3) Finally, storing the xml data.

XML Views:
Providing bidirectional mapping between XML schema's and relational tables.
Creation of XML Templates:
Allows creation of dynamic sections in XML.

Specifies a database user mapped to a certificate.

Specifies a database user mapped to a Windows group.

Specifies a database user with no corresponding server-level principal.

Specifies a principal from which the principal executing this query derives its right to grant the permission.

Specifies a database user mapped to an asymmetric key.

Specifies a database role.

Specifies an application role.

Specifies a database user mapped to a Windows user.

Indicates that the principal will also be given the ability to grant the specified permission to other principals.

Specifies a database user.

Specifies the principal to which the permission is being granted.

Specifies the XML schema collection on which the permission is being granted.

Specifies a permission that can be granted on an XML schema collection.

Syntax and example for creating and dropping XML schema collection:
★ CREATE XML SCHEMA COLLECTION [ <relational_schema>. ]sql_identifier AS Expression
★ relational_schema: identifies the relational schema name. Default is relational schema.
★ sql_identifier: is the SQL identifier for the XML schema collection.
★ Expression is a string constant or scalar variable. It can be a varchar, varbinary, nvarchar, or xml type.
★ DROP XML SCHEMA COLLECTION [ relational_schema. ]sql_identifier
relational_schema identifies the relational schema name.
sql_identifier is the name of the XML schema collection to drop.

The waterfall model is a popular version of the systems development life cycle model for software engineering. Often considered the classic approach to the systems development life cycle, the waterfall model describes a development method that is linear and sequential. Waterfall development has distinct goals for each phase of development. Imagine a waterfall on the cliff of a steep mountain. Once the water has flowed over the edge of the cliff and has begun its journey down the side of the mountain, it cannot turn back. It is the same with waterfall development. Once a phase of development is completed, the development proceeds to the next phase and there is no turning back

This enables MTS to reuse database connections. Database connections are sent to "sleep" mode as against normal constructions and destructions.

The Fill() method.

Abstract schema is part of an entity bean’s deployment descriptor which defines the bean’s persistent fields and their relationship. Abstract schema is specifed for entity beans with container managed persistence. We specify the name of the Abstract schema name in the deployment descriptor. The queries written in EJB QL for the finder methods references this name. The information provided in this Abstract Schema is used by the container for persistence management and relationship management.