Download Mining real world data

Mining real world data
RDBMS and SQL
Index
• RDBMS introduction
• SQL (Structured Query language)
RDBMS
• RDBMS stands for relational database management
systems.
• RDBMS imports the basic advantages of the DBMS
(Data base management systems).
• There are many advantages of using RDBMS for
storing relational data than other storage mechanisms.
• Few popular RDBMS examples include Sybase,
Oracle etc
Advantages of RDBMS
• Easy for backup and recovery.
• Easy accessibility and query based protocols ensure
good interactivity.
• Security and privacy ensured by maintenance of a key
(Primary / Foreign key)
• Supporting multiple format file structures with multi
level indexing.
SQL (Structured Query language)
• SQL is a popular query language used in RDBMS.
• SQL provides us with many clauses to view the kind
of data we need from the tables in the RDBMS. So
effectively SQL mines the RDBMS for patterns.
• Patterns are specified with clauses. Few of common
clauses and usage will be explained in the next slide.
SQL Clauses/ Query structure
• SELECT : Specifies what attributes from the table are
to be selected.
• FROM: Specifies the table name
• WHERE: Specifies the condition based on which we
want to extract records from the table.
• It also supports logical operators such as AND , OR
etc
Additional facilities
• SQL also supports nested queries using the IN clause.
• There are also facilities to join tables by specifying
the JOIN condition in the where clause to selectively
view tuples from multiple tables which satisfy a
certain condition.
• Aggregation operators such as MIN, MAX, SUM and
AVG are also supported.