Inconsistency of your mind.. Can damage your memory.. Romove the inconsistent data... And keep the original one only!!!
SQL stands for Structured Query Language, used to store, retrieve and manipulate data from a database. SQL is the standard language for RDBMS. SQL is one of the most commonly used query language on databases.
SQL offers two main advantages over older read–write APIs such as ISAM or VSAM. Firstly, it introduced the concept of accessing many records with one single command. Secondly, it eliminates the need to specify how to reach a record, e.g. with or without an index.
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Ted Codd in the early 1970s. This version was initially called SEQUEL (Structured English Query Language) and was designed to manipulate and retrieve data stored in IBM's original quasi-relational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1970s.
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