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Control Break Processing. ITE 370. Control Break Processing. Classic File Processing Technique Used in Main Frame Systems Used in Report Utilities Crystal Reports Designed to work on the file Regardless of Length Even if Length Changes Don’t hard code to file
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Control Break Processing ITE 370
Control Break Processing • Classic File Processing Technique • Used in Main Frame Systems • Used in Report Utilities • Crystal Reports • Designed to work on the file • Regardless of Length • Even if Length Changes • Don’t hard code to file • You know the design & makeup of file, but not content
Control Break Algorithm - Generic • ControlVar ‘* control variable which holds value of current group being processed • GrandTotal ‘* accumulator for whole file • GroupTotal ‘* accumulator for current group,(current value of ControlVar), displaying a sub-total • File ‘* file ordered by control variable, i.e. grouping variable • Row ‘* contains information from a row of File • .Info ‘* information on row to display • .SumField ‘* numeric data to sum for a group • .ControlField ‘* stores value for control variable, i.e. the grouping variable • BEGIN • File.Open • Row File.Read ‘* read first row of data from File • ControlVar Row.ControlField • Display Heading with ControlVar • GroupTotal 0 • GrandTotal 0 • While Not File.EOF • If Row.ControlField <> ControlVar Then • Display Sub-totals with GroupTotal • GrandTotal GrandTotal + GroupTotal • ControlVar Row.ControlField • Display Heading with ControlVar • GroupTotal 0 • End If • Display Row.Info, Row.SumField • GroupTotal GroupTotal + Row.SumField • Row File.Read ‘* read next row of data from file • End While • ‘* display sub-totals for last group • Display GroupTotal • GrandTotal GrandTotal + GroupTotal • Display GrandTotal • File.Close • END
Example • Print a report to include the names of baseball players and the number of home runs for each player, each team & total homeruns (grouped by team / nickname) • Requires: • Sequential File Processing (Data Reader) • Header • Detail Lines • Total Lines
Input File – Baseball (sorted by Control Variable - Nickname)
Baseball Example • Begin • Players.Open Open Data File • Players.Read Get player data from row.Read gives value to Row.Info • Team Player.Nickname, Assign Nickname to Control Var (Team) • Display Heading (Team) Output Team • TeamHR Initialize Group Total to 0 • TotalHR Initialize Grand Total to 0 • While Not Players.EOF While there are players, process the detail rows of report If Player.Nickname <> Team Then Check to see if the is the End of the Section • Display TeamHR Subtotals • TotalHR = TotalHR + TeamHR Increment Grand Totals • Team Player.Nickname, New Team Name • Display Heading Team • TeamHR = 0 Re-Initialize the Group Total for new Team • End IF Display (Players.Last, Player.HR) Output Players Name, Number of HR • TeamHR = TeamHR + PlayerHR Increment Group Total • Player Player.Read, Read next row • End While • Display TeamHT Display Team Subtotal • TotalHR = TotalHR + TeamHR Increment Grand Total • Display TotalHR Display Grand Total • Players.Close Close Data File • End
Variables • Control Variable – Holds the Value of the current control variable • Team Nickname • Counters and Accumulators • Group Totals • Team Homeruns • Grand Totals • Total Homeruns • Row Information • Player.Last • Sum Field – Player.HomeRuns • Control Field – Player.Nickname
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Row.Info (Player.Last) .Sum Field (Player.HR) .Control Field (Player.Nickname) Output
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Angels 0 41 0 Row.Info (Player.Last) .Sum Field (Player.HR) .Control Field (Player.Nickname) Smokey 41 Angels Output Angels: Smokey 41
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Angels 0 41 69 0 Row.Info (Player.Last) .Sum Field (Player.HR) .Control Field (Player.Nickname) Jones 28 Angels Output Angels: Smokey 41 Jones 28
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Angels 0 41 69 0 Row.Info (Player.Last) .Sum Field (Player.HR) .Control Field (Player.Nickname) Chapman 14 Orioles Output Angels: Smokey 41 Jones 28 69
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Orioles 0 14 0 69 Row.Info (Player.Last) .Sum Field (Player.HR) .Control Field (Player.Nickname) Chapman 14 Orioles Output Angels: Smokey 41 Jones 28 69 Orioles: Chapman 14
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Orioles 0 14 0 69 .Control Field (Player.Nickname) Row.Info (Player.Last) .Sum Field (Player.HR) Chapman 14 Orioles Output Angels: Smokey 41 Jones 28 69 Orioles: Chapman 14
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Red Sox 0 25 0 69 83 .Control Field (Player.Nickname) Row.Info (Player.Last) .Sum Field (Player.HR) Smith 25 Red Sox Output Angels: Smokey 41 Jones 28 69 Orioles: Chapman 14 14 Red Sox
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Red Sox 0 25 0 69 83 .Control Field (Player.Nickname) Row.Info (Player.Last) .Sum Field (Player.HR) Smith 25 Red Sox Output Angels: Red Sox Smokey 41 Smith 25 Jones 28 69 Orioles: Chapman 14 14
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Red Sox 0 25 54 0 69 83 .Control Field (Player.Nickname) Row.Info (Player.Last) .Sum Field (Player.HR) Brewer 29 Red Sox Output Angels: Red Sox Smokey 41 Smith 25 Jones 28 Brewer 29 69 Orioles: Chapman 14 14
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Red Sox 0 25 54 0 69 83 .Control Field (Player.Nickname) Row.Info (Player.Last) .Sum Field (Player.HR) Miller 15 White Sox Output Angels: Red Sox Smokey 41 Smith 25 Jones 28 Brewer 29 69 54 Orioles: Chapman 14 14
Walk Through Control Var (Team) Group Total (Team HR) Grand Total (Total HR) Control Var (Team) Group Total (Team HR) Grand Total (Total HR) White Sox 0 15 0 69 83 137 .Control Field (Player.Nickname) Row.Info (Player.Last) .Sum Field (Player.HR) Miller 15 White Sox Output Angels Red Sox Smokey 41 Smith 25 Jones 28 Brewer 29 69 54 Orioles White Sox Chapman 14 Miller 15 14
Final Output Angels Smokey 41 Jones 28 Team HR 69 Orioles Chapman 14 Team HR 14 Red Sox Smith 25 Brewer 29 Team HR 54 White Sox Miller 15 Kennedy 35 Parker 40 Jackson 29 Team HR 119 Total HR 256
Control Break Processing • Program 1 • You must determine when the section breaks need to occur • Requirements: • Connection Object • Command Object (SQL Command) • Data Reader Object • Read / Compare Items in Data Reader Object