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An early such system was IBM's Information Management System , which is still widely deployed more than 50 years later. IMS stores information hierarchically, however within the Nineteen Seventies Ted Codd proposed another relational storage model based on set principle and predicate logic and the acquainted concepts of tables, rows ,and columns. In 1981, the primary commercially available relational database management system was launched by Oracle. Toxic substances from farms, towns, and factories readily dissolve into and blend with it, causing water pollution. Still, we’re not hopeless towards the threat to wash water. To better perceive the issue and what we are in a position to do about it, here’s an overview of what water pollution is, what causes it, and the way we can shield ourselves. Sip a glass of cool, clear water as you learn this, and you may suppose water pollution is an issue . But while most Americans have entry to secure drinking water, doubtlessly dangerous ...