Social Interaction in Databases - Community-Built Databases: Research and Development - page 165

Fig. 7.1 A social database
system

Social
Database

Traditional
Database

User Social
Network/
User
similarity

Database
Data

Private
Views

Master
Table

Users

7.5 Private Views

Our approach is to create a flexible, dynamic layer between the database, on one
end, and the user on the other. We call this layer a since it is devoted

to collecting, for a given user u , all the data generated by u and make such data
accessible to u only although we will see later that u may choose to make the data
accessible to others.
It is important to point out that our extension, while adding functionality to
existing database technology, is conservative ; that is, it works within the relational
database model as much as possible. This maximizes the chances of the approach
being implementable in current platforms, without requiring major changes or
creating conceptual conflicts with existing technology.
We divide user-created content with respect to two fundamental dimensions:

private view

. Since all user-created content is assumed to be parasitic,
it is the case that each piece of content is linked to either data (a cell, a row, a set
of rows) or metadata (an attribute, or a set of attributes). Since we want to be
flexible, we allow the data reference to be any user command (SQL query or
write statement). Note that in a relational database, metadata is also stored in
tables (usually called Catalog tables or system tables ) and hence an SQL query
over such tables identifies metadata. In fact, we assume that most user-created
content will be attached to metadata .
l What type of data it is . We distinguish between internal data, that is, data that the
user creates and enters in the database, and external data , that is, a data that
already exists outside the database (a document, a web page, etc.). For external
data, we define a link type. Internal data is characterized as either structured
(having a tuple structure) or unstructured (a tag or a comment).

What it is attached to

l