Relational Database
Relational DatabaseA data set collected to depict related data in the form of a table is calleda relational database.A table consists of "Rows" and "Columns". "Rows" is equivalent to recordsin the file, and "Columns" is equivalent to fields.Student table, for exampleHere are three data operations in relational databases.①Selection"Selection" is the operation to retrieve the rows that fulfill the conditions fromthe designated table.②Projection"Projection" is the operation to retrieve the columns that fulfill the conditionsfrom the designated table.③JoinExtract the required columns from multiple tables, combine them into one,and create a new table. These operations are called "Join".For exampl
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