DeleteFeature

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.  使用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、DeleteSearchedRows和ExecuteSQL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,建议马上修改程序。

4、数据量大于500000条建议使用DeleteSearchedRows或ExecuteSQL,否则使用更新游标删除(方法2),加上进度条,这样界面很友好。

转载自:https://blog.csdn.net/kone0611/article/details/50834786

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