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Database PowerPoint Presentation Lectures by Dr Patrick Ozoh Dept of ICT Osun State University

A transaction is a sequence of DML commands that forms a logical unit of work Example: transferring money from one bank account to another Transaction Management A transaction is a sequence of DML commands that forms a logical unit of work Example: transferring money from one bank account to another Some Definitions Atomicity - a transaction must execute completely or not at all Consistency - once a transaction completes successfully, the database must be in a consistent state Isolation: A transaction must not be affected by other transactions that are executing concurrently Durability: Once a transaction compketes successfully, its effect must persist even in the presence of system failures Concurrency control Concurrency control is a database management systems (DBMS) concept meant to coordinate simultaneous transactions while preserving data integrity. Control protocols ensures atomicity, isolation, and serializability of concurrent transactions Concurrency control protoc

Osun State University in Collaboration with British Computer Society

Become a BCS Associate member for free on gaining a certification and enjoy all the benefits of membership Gain an internationally- recognized  certification, enabling you to take your skills around the world Map your skills and identify your goals along your career path by following the SFIAplus industry-standard framework Get certified !!! The British Computer Society Chartered Institute of IT Professionals Foundation in Business Analysis Register using the following link https://docs.google.com/forms/d/e/1FAIpQLSc95O9kEpLfxtqpwV5ofhS-qVv3AlDk7T2SfVRRMm829-VKEw/viewform Lecture materials can be accessed freely by joining the following link https://chat.whatsapp.com/9n1rTFD8dM97pLYJVEZQec  

Database System Concepts - SQL

  SQL (Structured Query Language) is THE standard DML for relational database products. The query language is based on relational algebra, but borrows from tuple relational calculus. Topics: •  the data-definition language (DDL) - creating, deleting and modifying relation   schemas •  the data-manipulation language (DML) - the query   language •  modification of relations (insert, delete,   update) •  integrity constraints (domain constraints and foreign   keys) •  creation and use of   views •  transaction   control •  application   programming Five major standards have been defined for SQL: •  SQL-86 •  SQL-89 •  SQL-92 •  SQL:1999 •  SQL:2003 Each standard is essentially a superset of the previous ones. Most major commercial systems support essentially the SQL-92 standard along with some part of the SQL:1999 and SQL:2003 standards. In the following examples, we continue to use the flyshop database with the following schema (primary  key attributes   underlined):   schema name attrib