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statistical operations. Such calculations as net present value or standard
deviation can be applied to tabular data with a pre-programmed function in a
formula. Spreadsheet programs also provide conditional expressions, functions to
convert between text and numbers, and functions that operate on strings of text.
In modern spreadsheet applications, several spreadsheets, often known
as
worksheets or simply
sheets, are gathered together to form a
workbook. A
workbook is physically represented by a file containing all the data for the book,
the sheets, and the cells with the sheets. Worksheets are normally represented by
tabs that flip between pages, each one containing one of the sheets,
although Numbers changes this model significantly. Cells in a multi-sheet book
add the sheet name to their reference, for instance. Some systems extend this
syntax to allow cell references to different workbooks.
Spreadsheets share many principles and traits of databases, but
spreadsheets and databases are not the same things. A spreadsheet is essentially
just one table, whereas a database is a collection of many tables with machine-
readable semantic relationships. While it is true that a workbook that contains
three sheets is indeed a file containing multiple tables that can interact with each
other, it lacks the relational structure of a database. Spreadsheets and databases
are interoperable sheets can be imported into databases to become tables within
them, and database queries can be exported into spreadsheets for further analysis.
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