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通用查询组件设计

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< AN lang=EN-US>procedure TMyFieldInfo.SetVariables(d: TDataset);

var

< AN style="mso- acerun: yes"> value : String;

begin

//设置变量值

< AN style="mso- acerun: yes"> if A iU erCase(FilterValue) = 'NULL' then //如果FilterValue为空，则退出

< AN style="mso- acerun: yes"> exit;

< AN style="mso- acerun: yes"> if FieldType = ftString then //如果字段类型为字符串型，则

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if CaseSe itive the //如果大小写敏感

< AN style="mso- acerun: yes"> case MatchType of //匹配类型

< AN style="mso- acerun: yes"> fdMatchStart, fdMatchAny : //起始部分匹配或任意位置匹配

< AN style="mso- acerun: yes"> value := FilterValue;

< AN style="mso- acerun: yes"> fdMatchEnd : //结束部分匹配

< AN style="mso- acerun: yes"> value := '%' + FilterValue

< AN style="mso- acerun: yes"> fdMatchExact : //非匹配记录

< AN style="mso- acerun: yes"> value := FilterValue;

< AN style="mso- acerun: yes"> end

else< AN style="mso- acerun: yes"> //大小写不敏感

< AN style="mso- acerun: yes"> case MatchType of

< AN style="mso- acerun: yes"> fdMatchStart, fdMatchAny : //起始部分匹配或任意位置匹配

< AN style="mso- acerun: yes"> value := A iU erCase(FilterValue);

< AN style="mso- acerun: yes"> fdMatchEnd : //结束部分匹配

< AN style="mso- acerun: yes"> value := '%' + A iU erCase(FilterValue) {do not localize}

< AN style="mso- acerun: yes"> fdMatchExact : //非匹配记录

< AN style="mso- acerun: yes"> value := A iU erCase(FilterValue);

< AN style="mso- acerun: yes"> end;

< AN style="mso- acerun: yes"> end

< AN style="mso- acerun: yes"> else//字段类型为非字符串型

< AN style="mso- acerun: yes"> value := FilterValue;

< AN style="mso- acerun: yes"> if MatchType < gt; fdMatchRange then//如果匹配类型不为按范围

TQuery(d).ParamByName(FieldName + 'Filter').Value :=< AN style="mso- acerun: yes"> value

else //否则

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if CaseSe itive then //如果大小写敏感

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if StartingValue < gt; '' then //如果起始范围值不为空　

< AN style="mso- acerun: yes"> TQuery(d).ParamByName(FieldName + 'Start').Value := StartingValue

< AN style="mso- acerun: yes"> if EndingValue < gt; '' then //如果结束范围不为空

< AN style="mso- acerun: yes"> TQuery(d).ParamByName(FieldName + 'End').Value := EndingValue

< AN style="mso- acerun: yes"> end

< AN style="mso- acerun: yes"> else //大小写敏感

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if StartingValue < gt; '' then //如果起始范围值不为空

< AN style="mso- acerun: yes"> TQuery(d).ParamByName(FieldName + 'Start').Value := A iU erCase(StartingValue);

< AN style="mso- acerun: yes"> if EndingValue < gt; '' then //如果结束范围值不为空

< AN style="mso- acerun: yes"> TQuery(d).ParamByName(FieldName + 'End').Value := A iU erCase(EndingValue)

< AN style="mso- acerun: yes"> end;

< AN style="mso- acerun: yes"> end

end;

< AN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-ha i-font-family: 'Times New Roman'">字段定义类

TMyFieldInfo = cla < AN style="mso- acerun: yes"> //字段类

< AN style="mso- acerun: yes"> public

< AN style="mso- acerun: yes"> FieldName : String //字段名

< AN style="mso- acerun: yes"> FieldOrigin : String

< AN style="mso- acerun: yes"> FieldType : TFieldType //字段类型

< AN style="mso- acerun: yes"> Di layLabel : String //显示的名称

< AN style="mso- acerun: yes"> MatchType : TDBFilterMatchType //匹配类型

< AN style="mso- acerun: yes"> FilterValue : String; //过滤值

< AN style="mso- acerun: yes"> StartingValue : String; //开始值

< AN style="mso- acerun: yes"> EndingValue : String //结束值

< AN style="mso- acerun: yes"> CaseSe itive : boolea //是否大小写敏感

< AN style="mso- acerun: yes"> NonMatching : boolea //不匹配

< AN style="mso- acerun: yes"> procedure A ign(o : TMyFieldInfo); //指定字段定义

function CreateSQL : String;< AN style="mso- acerun: yes"> //创建SQL语句

procedure SetVariables( d : TDataset);< AN style="mso- acerun: yes"> //设置字段变量

< AN style="mso- acerun: yes"> end;

< AN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-ha i-font-family: 'Times New Roman'">指定字段定义

procedure TMyFieldInfo.A ign(o : TMyFieldInfo);

begin

//指定字段信息

< AN style="mso- acerun: yes"> FieldName := o.FieldName;

< AN style="mso- acerun: yes"> FieldOrigin := o.FieldOrigi

< AN style="mso- acerun: yes"> FieldType := o.FieldType;

< AN style="mso- acerun: yes"> Di layLabel := o.Di layLabel;

< AN style="mso- acerun: yes"> MatchType := o.MatchType;

< AN style="mso- acerun: yes"> FilterValue := o.FilterValue;

< AN style="mso- acerun: yes"> StartingValue := o.StartingValue;

< AN style="mso- acerun: yes"> EndingValue := o.EndingValue;

< AN style="mso- acerun: yes"> CaseSe itive := o.CaseSe itive;

< AN style="mso- acerun: yes"> NonMatching := o.NonMatching;

end;

< AN style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-ha i-font-family: 'Times New Roman'">创建SQL语句

function TMyFieldInfo.CreateSQL: String;

var

< AN style="mso- acerun: yes"> Field : String;

begin

//创建SQL语句

< AN style="mso- acerun: yes"> if FieldOrigin < gt; '' then

< AN style="mso- acerun: yes"> Field := FieldOrigin

< AN style="mso- acerun: yes"> else

< AN style="mso- acerun: yes"> Field := FieldName;

< AN style="mso- acerun: yes"> if NonMatching then

< AN style="mso- acerun: yes"> Result := ' not ( '

< AN style="mso- acerun: yes"> else

< AN style="mso- acerun: yes"> Result := ' ( ';

< AN style="mso- acerun: yes"> if A iU erCase(FilterValue) = 'NULL' then

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> Result := Result + Format('%s is NULL) ', [Field]);

< AN style="mso- acerun: yes"> exit;

< AN style="mso- acerun: yes"> end;

< AN style="mso- acerun: yes"> if FieldType = ftString then

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if CaseSe itive then

< AN style="mso- acerun: yes"> case MatchType of

< AN style="mso- acerun: yes"> fdMatchStart:

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s starting with :%1:sFilter ) ', [Field, FieldName]);

< AN style="mso- acerun: yes"> fdMatchAny:

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s containing :%1:sFilter ) ', [Field, FieldName]);

< AN style="mso- acerun: yes"> fdMatchEnd :

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s = :%1:sFilter ) ', [Field, FieldName]);

< AN style="mso- acerun: yes"> fdMatchExact :

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s = :%1:sFilter ) ', [Field, FieldName]);

< AN style="mso- acerun: yes"> fdMatchRange :

< AN style="mso- acerun: yes"> egin

< AN style="mso- acerun: yes"> if StartingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s >= :%1: tart)', [Field, FieldName]);

< AN style="mso- acerun: yes"> if (StartingValue < gt; '') and (EndingValue < gt; '') then

< AN style="mso- acerun: yes"> Result := Result + ' and (';

< AN style="mso- acerun: yes"> if EndingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s <= :%1:sEnd)', [Field, FieldName]);

< AN style="mso- acerun: yes"> end;

< AN style="mso- acerun: yes"> end

< AN style="mso- acerun: yes"> else

< AN style="mso- acerun: yes"> case MatchType of

< AN style="mso- acerun: yes"> fdMatchStart:

< AN style="mso- acerun: yes"> Result := Result + Format('U ER(%0:s) starting with :%1:sFilter ) ', [Field, FieldName]); {do not localize}

< AN style="mso- acerun: yes"> fdMatchAny:

< AN style="mso- acerun: yes"> Result := Result + Format('U ER(%0:s) containing :%1:sFilter ) ', [Field, FieldName]); {do not localize}

< AN style="mso- acerun: yes"> fdMatchEnd :

< AN style="mso- acerun: yes"> Result := Result + Format('U ER(%0:s) like :%1:sFilter ) ', [Field, FieldName]) {do not localize}

< AN style="mso- acerun: yes"> fdMatchExact :

< AN style="mso- acerun: yes"> Result := Result + Format('U ER(%0:s) = :%1:sFilter ) ', [Field, FieldName]) {do not localize}

< AN style="mso- acerun: yes"> fdMatchRange :

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if FieldType = ftString then

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if StartingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('U ER(%0:s) >= :%1: tart)', [Field, FieldName]); {do not localize}

< AN style="mso- acerun: yes"> if (StartingValue < gt; '') and (EndingValue < gt; '') then

< AN style="mso- acerun: yes"> Result := Result + ' and (' {do not localize}

< AN style="mso- acerun: yes"> if EndingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('U ER(%0:s) <= :%1:sEnd)', [Field, FieldName]); {do not localize}

< AN style="mso- acerun: yes"> end

< AN style="mso- acerun: yes"> else

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if StartingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s >= :%1: tart)', [Field, FieldName]) {do not localize}

< AN style="mso- acerun: yes"> if (StartingValue < gt; '') and (EndingValue < gt; '') then

< AN style="mso- acerun: yes"> Result := Result + ' and (' {do not localize}

< AN style="mso- acerun: yes"> if EndingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s <= :%1:sEnd)', [Field, FieldName]) {do not localize}

< AN style="mso- acerun: yes"> end

< AN style="mso- acerun: yes"> end;

< AN style="mso- acerun: yes"> end

< AN style="mso- acerun: yes"> else

< AN style="mso- acerun: yes"> case MatchType of

< AN style="mso- acerun: yes"> fdMatchRange :

< AN style="mso- acerun: yes"> begin

< AN style="mso- acerun: yes"> if StartingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s >= :%1: tart)', [Field, FieldName]); {do not localize}

< AN style="mso- acerun: yes"> if (StartingValue < gt; '') and (EndingValue < gt; '') then

< AN style="mso- acerun: yes"> Result := Result + ' and ('; {do not localize}

< AN style="mso- acerun: yes"> if EndingValue < gt; '' then

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s <= :%1:sEnd)', [Field, FieldName]) {do not localize}

< AN style="mso- acerun: yes"> end;

< AN style="mso- acerun: yes"> else

< AN style="mso- acerun: yes"> Result := Result + Format('%0:s = :%1:sFilter ) ', [Field, FieldName]); {do not localize}

< AN style="mso- acerun: yes"> end;

end;

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