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Published byMorgan Francis Modified over 9 years ago
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Mining real world data RDBMS and SQL
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Index RDBMS introduction SQL (Structured Query language)
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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
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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.
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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.
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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
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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.
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