Standard search Engine earch: Vianu logical databases 日DDD a document containing some of the three quer terms is considered as a result 16
16 Standard Search Engine A document containing some of the three query terms is considered as a result
The document contains the three query terms Hence, it is returned by a standard search engine. BUT <proceedings> <inproceedings> <author>Moshe Vardi</author> <title>Querying logical patabasesk/title> </inproceedings> <inproceedings> <author>victor ianuk/author> <title>A Web Odyssey: From Codd to Ⅺ</tit1e> </inproceedings> </proceedings> 17
17 The document is not relevant to the query. This does not work!!! The document is returned BUT it does not contain any paper on “logical databases” by Vianu This fragment does not represent a paper about logical databases a paper by Vianu <proceedings> <inproceedings> <author>Moshe Y. Vardi</author> <title>Querying Logical Databases</title> </inproceedings> <inproceedings> <author>Victor Vianu</author> <title>A Web Odyssey: From Codd to XML</title> </inproceedings> </proceedings> The document contains the three query terms. Hence, it is returned by a standard search engine. BUT
Relationship Trees Relationship tree of Lowest common ,n2,…,k ancestor of 1,712, 18
18 Relationship Trees Relationship tree of n1 , n2 , …, nk n1 n2 … nk Lowest common ancestor of n1 , n2 , …, nk
XSEarch A Semantic Search Engine for XN 1,.,n, are interconnected if either relationship tree of n,,, nk does not contain two nodes with the same label, or the only nodes with the same label in the relationship tree of n灬…,nk, are among n1…, k 19
19 XSEarch: A Semantic Search Engine for XML • n1 ,..., nk are interconnected if either – relationship tree of n1 ,..., nk does not contain two nodes with the same label, or – the only nodes with the same label in the relationship tree of n1 ,..., nk , are among n1 ,..., nk
Lowest common EXample (1) ancestor of circled de Relationship Daes tree proceedings inproceedings inproceedings author)/title title autho Moshe y Vardi Querying Victor A Web Odyssey: Logical Vianu From Codd to XML Databases Circled nodes belong to different inproceedings entities They are not interconnected
20 proceedings Moshe Y. Vardi inproceedings author title Querying Logical Databases author title Victor Vianu A Web Odyssey: From Codd to XML inproceedings Circled nodes belong to different inproceedings entities. They ARE NOT interconnected! Relationship tree Lowest common ancestor of circled nodes Example (1)