IBM, through the work of Edgar Codd, invented the ideas behind the relational database back in 1970
Timothy Prickett Morgan writes in The Next Platform,
"Even though IBM Research created the System R database in 1974 and had a few customers for this research effort, and even though its 'Pacific' project integrated a relational database into an object-based operating system to create the System/38 back in 1978 - a very advanced machine for its day that still lives on in the Power Systems family running the IBM i operating system - it is Oracle that gets credit for commercializing the relational database.
Perhaps that is justified because IBM didn't really sell more than a few tens of thousands of System/38s in their decade of availability and moreover Big Blue did not get a relational database, called SQL/DS, out on mainframes until 1981 and did not get its flagship DB2 database running on mainframes until 1983..."
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