Please provide full answer to the following questions with exampls 1What are the

Question

Please provide full answer to the following questions with exampls

1What are the differences between bucket and chain?

2.explain in details the extendible hashing index operation, including insertion, deletion, and search.

3.explain the information integration, and two main integration techniques.

4.What is XML? What is DTD?

4.What is Well-formed XML? What is Valid XML?

5.what is the basic XML and DTD syntax.

6.what is the basic syntax of XPATH and XQuery.

7.write XQuery to search for specific items from a XML file

Explanation / Answer

3)Answer:

information integration:

Information integration (II) is the merging of information from heterogeneous sources with differing conceptual, contextual and typographical representations. It is used in data mining and consolidation of data from unstructured or semi-structured resources. Typically, information integration refers to textual representations of knowledge but is sometimes applied to rich-media content. Information fusion, which is a related term, involves the combination of information into a new set of information towards reducing redundancy and uncertainty

Information integration refers to the field of study of techniques attempting to combine information from disparate sources despite differing conceptual, contextual and lexical representations. One goal of information integration, commonly held by the data management community, is to combine the information in such a way that the user gets a unified view of the data. In other words, the user should see and query the data as though it is present in a common, unified schema.

In the domain of scientific applications, the problems and expectations are different. In this domain the semantics of data play a very strong role in data integration, and semantic compatibility need to be ensured as part of the data integration process.

4)Answer:

XML:

Extensible Markup Language (XML) is a universal format maintained by the W3C used for representation and transfer of structured data on the web or between different applications.

The language uses a structured representation by allowing user to create custom defined tags according to XML Document Type Definition (DTD) standards. The structure of XML document can be represented in the form of a tree known as Document Object Model (DOM)

XML is designed to describe data but is not concerned with the data's visualization. The tags created in XML are self explanatory and the user is free to define their own tags - hence the extensible.

XML support is provided by many programming language platforms to create and process XML data. Simplicity, portability, platform independence, usability are some of the key features that have resulted in the increasing popularity of the use of XML based standards.

XML has been the main source of motivation for development of Service Oriented Architecture (SOA) platforms such as Web Services that are not tied to any particular language and collaborate effectively in heterogeneous environments. RSS, Atom, SOAP, XHTML are some of the standards influenced by XML

DTD:

Document type definition (DTD) refers to a set of markup declarations that define a document type for Standard Generalized Markup Language (SGML) languages. DTDs define the structure of a class of documents through element and attribute-list declarations. DTD helps parsers validate documents. It is officially recommended by the World Wide Web Consortium (W3C). DTDs have now been largely superseded by XML Namespace-aware schema languages

DTDs make two types of declarations: Internal: Forms part of the document itself and is inserted within the DOCTYPE definition near the start of the XML document. External: Points to DTD declarations contained in an external file. For security reasons, parsers and Web browsers may be prevented from reading external subsets. DTDs describe the structure of a class of documents via element and attribute-list declarations. Element declarations name the allowable set of elements within the document, and specify whether and how declared elements and runs of character data may be contained within each element. Attribute-list declarations name the allowable set of attributes for each declared element, including the type of each attribute value, or an explicit set of valid value(s). DTD markup declarations declare which element types, attribute lists, entities and notations are allowed in the structure of the corresponding class of XML documents. DTDs have certain limitations that are related to their flexibility: Differences between the DTD syntax and the XML syntax Lack of namespace awareness Lack of data typing Limited content model descriptions.

Well-formed XML:

An XML document is called well-formed if it satisfies certain rules, specified by The W3C.

These rules are:

valid XML:

Valid XML is XML that succeeds validation against a DTD. Well formed XML is XMLthat has all tags closed in the proper order and, if it has a declaration, it has it first thing in the file with the proper attributes. In other words, validity refers to semantics, well-formedness refers to syntax.

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