Proračunska tabela

Један корисник управо ради на овом чланку. Молимо остале кориснике да му допусте да заврши са радом. Ако имате коментаре и питања у вези са чланком, користите страницу за разговор. Хвала на стрпљењу. Када радови буду завршени, овај шаблон ће бити уклоњен. Напомене Шаблон је застарео уколико је прошло дуже од 72 сата од последње измене на чланку. Последњу измену на овој страници начинио је корисник Dcirovic (разговор · доприноси), на датум 7. децембар 2019. у 00:47. Није препоручљиво да један корисник овим шаблоном обележи више од једног чланка. Молимо вас да између уређивачких сеанси уклоните овај шаблон са чланка, како бисте омогућили и другим корисницима да неометано уређују и исправљају чланак. Шаблон не ограничава друге уреднике да уређују означену страницу али необавезујућа препорука јесте да се чланак значајније не уређује док уредник који ради на чланку не уклони исти.

Proračunska tabela je interaktivna računarska aplikacija za organizaciju, analizu i čuvanje podataka u tabularnom formatu.^[1][2][3] Spreadsheets were developed as computerized analogs of paper accounting worksheets.^[4] The program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the results of formulas that automatically calculate and display a value based on the contents of other cells. A spreadsheet may also refer to one such electronic document.^[5][6][7]

Spreadsheet users can adjust any stored value and observe the effects on calculated values. This makes the spreadsheet useful for "what-if" analysis since many cases can be rapidly investigated without manual recalculation. Modern spreadsheet software can have multiple interacting sheets, and can display data either as text and numerals, or in graphical form.

Besides performing basic arithmetic and mathematical functions, modern spreadsheets provide built-in functions for common financial and 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.

Spreadsheets have replaced paper-based systems throughout the business world. Although they were first developed for accounting or bookkeeping tasks, they now are used extensively in any context where tabular lists are built, sorted, and shared.

LANPAR, available in 1969,^[8] was the first electronic spreadsheet on mainframe and time sharing computers. LANPAR was an acronym: LANguage for Programming Arrays at Random.^[8] VisiCalc was the first electronic spreadsheet on a microcomputer,^[9] and it helped turn the Apple II computer into a popular and widely used system. Lotus 1-2-3 was the leading spreadsheet when DOS was the dominant operating system.^[10] Excel now has the largest market share on the Windows and Macintosh platforms.^[11][12][13] A spreadsheet program is a standard feature of an office productivity suite; since the advent of web apps, office suites now also exist in web app form. Web based spreadsheets are a relatively new category.

While spreadsheets represented a major step forward in quantitative modeling, they have deficiencies. Their shortcomings include the perceived unfriendliness of alpha-numeric cell addresses.^[14]

• Research by ClusterSeven has shown huge discrepancies in the way financial institutions and corporate entities understand, manage and police their often vast estates of spreadsheets and unstructured financial data (including comma-separated values (CSV) files and Microsoft Access databases). One study in early 2011 of nearly 1,500 people in the UK found that 57% of spreadsheet users have never received formal training on the spreadsheet package they use. 72% said that no internal department checks their spreadsheets for accuracy. Only 13% said that Internal Audit reviews their spreadsheets, while a mere 1% receive checks from their risk department.^[15]
• Spreadsheets have significant reliability problems. Research studies estimate that roughly 94% of spreadsheets deployed in the field contain errors, and 5.2% of cells in unaudited spreadsheets contain errors.^[16]

Despite the high error risks often associated with spreadsheet authorship and use, specific steps can be taken to significantly enhance control and reliability by structurally reducing the likelihood of error occurrence at their source.^[17]

• The practical expressiveness of spreadsheets can be limited unless their modern features are used. Several factors contribute to this limitation. Implementing a complex model on a cell-at-a-time basis requires tedious attention to detail. Authors have difficulty remembering the meanings of hundreds or thousands of cell addresses that appear in formulas.

These drawbacks are mitigated by the use of named variables for cell designations, and employing variables in formulas rather than cell locations and cell-by-cell manipulations. Graphs can be used to show instantly how results are changed by changes in parameter values. In fact, the spreadsheet can be made invisible except for a transparent user interface that requests pertinent input from the user, displays results requested by the user, creates reports, and has built-in error traps to prompt correct input.^[18]

• Similarly, formulas expressed in terms of cell addresses are hard to keep straight and hard to audit. Research shows that spreadsheet auditors who check numerical results and cell formulas find no more errors than auditors who only check numerical results.^[16] That is another reason to use named variables and formulas employing named variables.

Specifically, spreadsheets typically contain many copies of the same formula. When the formula is modified, the user has to change every cell containing that formula. In contrast, most computer languages allow a formula to appear only once in the code, and achieve repetition by means of loops: making them much easier to implement and audit.

• The alteration of a dimension demands major surgery. When rows (or columns) are added to or deleted from a table, one has to adjust the size of many downstream tables that depend on the table being changed. In the process, it is often necessary to move other cells around to make room for the new columns or rows, and to adjust graph data sources. In large spreadsheets, this can be extremely time consuming.^[19][20]
• Adding or removing a dimension is so difficult, one generally has to start over. The spreadsheet as a paradigm really forces one to decide on dimensionality right of the beginning of one's spreadsheet creation, even though it is often most natural to make these choices after one's spreadsheet model has matured. The desire to add and remove dimensions also arises in parametric and sensitivity analyses.^[19][20]
• Collaboration in authoring spreadsheet formulas can be difficult when such collaboration occurs at the level of cells and cell addresses.

Other problems associated with spreadsheets include:^[21][22]

• Some sources advocate the use of specialized software instead of spreadsheets for some applications (budgeting, statistics)^[23][24][25]
• Many spreadsheet software products, such as Microsoft Excel^[26] (versions prior to 2007) and OpenOffice.org Calc^[27] (versions prior to 2008), have a capacity limit of 65,536 rows by 256 columns (2¹⁶ and 2⁸ respectively). This can present a problem for people using very large datasets, and may result in data loss.
• Lack of auditing and revision control. This makes it difficult to determine who changed what and when. This can cause problems with regulatory compliance. Lack of revision control greatly increases the risk of errors due the inability to track, isolate and test changes made to a document.
• Lack of security. Spreadsheets lack controls on who can see and modify particular data. This, combined with the lack of auditing above, can make it easy for someone to commit fraud.^[28]
• Because they are loosely structured, it is easy for someone to introduce an error, either accidentally or intentionally, by entering information in the wrong place or expressing dependencies among cells (such as in a formula) incorrectly.^[19][29][30]
• The results of a formula (example "=A1*B1") applies only to a single cell (that is, the cell the formula is actually located in—in this case perhaps C1), even though it can "extract" data from many other cells, and even real time dates and actual times. This means that to cause a similar calculation on an array of cells, an almost identical formula (but residing in its own "output" cell) must be repeated for each row of the "input" array. This differs from a "formula" in a conventional computer program, which typically makes one calculation that it applies to all the input in turn. With current spreadsheets, this forced repetition of near identical formulas can have detrimental consequences from a quality assurance standpoint and is often the cause of many spreadsheet errors. Some spreadsheets have array formulas to address this issue.
• Trying to manage the sheer volume of spreadsheets that may exist in an organization without proper security, audit trails, unintentional introduction of errors, and other items listed above can become overwhelming.

While there are built-in and third-party tools for desktop spreadsheet applications that address some of these shortcomings, awareness and use of these is generally low. A good example of this is that 55% of Capital market professionals "don't know" how their spreadsheets are audited; only 6% invest in a third-party solution^[31]

Proračunska tabela на Викимедијиној остави.

• A Spreadsheet Programming article on DevX
• comp.apps.spreadsheets FAQ by Russell Schulz
• Extending the Concept of Spreadsheet by Jocelyn Paine
• Proračunska tabela на сајту Curlie (језик: енглески)
• Spreadsheet – Its First Computerization (1961–1964) by Richard Mattessich
• CICS history and introduction of IBM 3270 by Bob Yelavich
• Autoplan & Autotab article by Creative Karma
• Spreadsheets in Science