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2009-07-09 09:25:18

一、  几种删除方法代码

1.  查询结果中删除

  private void Delete1(IFeatureClass PFeatureclass)

        {

            IQueryFilter pQueryFilter = new QueryFilterClass();

            pQueryFilter.WhereClause = "objectID<=" + DeleteNum;

            IFeatureCursor pFeatureCursor = PFeatureclass.Search(pQueryFilter, false);            IFeature pFeature = pFeatureCursor.NextFeature();

            while (pFeature != null)

            {

                pFeature.Delete();

                pFeature = pFeatureCursor.NextFeature();

            }

            System.Runtime.InteropServices.Marshal.ReleaseComObject(pQueryFilter);

        }

2.  更新游标删除

private void Delete2(IFeatureClass PFeatureclass)

        {

            IQueryFilter pQueryFilter = new QueryFilterClass();

            pQueryFilter.WhereClause = "objectID<=" + DeleteNum;

            IFeatureCursor pFeatureCursor = PFeatureclass.Update(pQueryFilter, false);

            IFeature pFeature = pFeatureCursor.NextFeature();

            while (pFeature != null)

            {

                pFeatureCursor.DeleteFeature();

                pFeature = pFeatureCursor.NextFeature();

            }

            System.Runtime.InteropServices.Marshal.ReleaseComObject(pQueryFilter);

 

        }

3.  使用DeleteSearchedRows删除

private void Delete4(IFeatureClass PFeatureclass)

        {

            IQueryFilter pQueryFilter = new QueryFilterClass();

            pQueryFilter.WhereClause = "objectID<=" + DeleteNum;

            ITable pTable = PFeatureclass as ITable;

            pTable.DeleteSearchedRows(pQueryFilter);

            System.Runtime.InteropServices.Marshal.ReleaseComObject(pQueryFilter);

        }

 

4.  ExecuteSQL删除

private void Delete4(IFeatureClass PFeatureclass)

        {

            IDataset pDataset = PFeatureclass as IDataset;

            pDataset.Workspace.ExecuteSQL("delete from " + PFeatureclass.AliasName + " where objectid<=" + DeleteNum);

        }

二、  测试性能和比较

1       相同的数据条件,删除2000条记录

2       测试代码

IFeatureLayer pFeatureLayer = axMapControl1.Map.get_Layer(0) as IFeatureLayer;

            IFeatureClass PFeatureClass = pFeatureLayer.FeatureClass;

            System.Diagnostics.Stopwatch MyWatch = new System.Diagnostics.Stopwatch();

            MyWatch.Start();

            Delete1(PFeatureClass)

            //Delete2(PFeatureClass);

            //Delete3(PFeatureClass);

            //Delete4(PFeatureClass);

            //Delete5(PFeatureClass);

            MyWatch.Stop();

            MessageBox.Show("删除时间:" + MyWatch.ElapsedMilliseconds.ToString() + "毫秒");

3       测试情况

测试方法

第一次时间(单位ms

第一次时间(单位ms

1

5214ms

5735ms

2

299ms

290Ms

3

59ms

28ms

4

26ms

26ms

三、  结论

1         使用ExecuteSQL删除最快,数据库的效率最高。

2         DeleteSearchedRowsExecuteSQL属于批量删除,性能较优。

3         查询结果中删除,速度最慢,如果你使用这种方法,建立你马上修改你的程序,因为你在浪费时间。

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