ArcGIS Pro SDK （八）地理数据库 4 查询

ArcGIS Pro SDK （八）地理数据库 4 查询

环境：Visual Studio 2022 + .NET6 + ArcGIS Pro SDK 3.0

1 使用查询筛选器搜索表

public async Task SearchingATable()
{try{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))using (Table table = geodatabase.OpenDataset<Table>("EmployeeInfo")){QueryFilter queryFilter = new QueryFilter{WhereClause = "COSTCTRN = 'Information Technology'",SubFields = "KNOWNAS, OFFICE, LOCATION",PostfixClause = "ORDER BY OFFICE"};using (RowCursor rowCursor = table.Search(queryFilter, false)){while (rowCursor.MoveNext()){using (Row row = rowCursor.Current){string location = Convert.ToString(row["LOCATION"]);string knownAs = Convert.ToString(row["KNOWNAS"]);}}}}});}catch (GeodatabaseFieldException fieldException){// 处理字段异常}catch (Exception exception){// 处理其他异常}
}

2 在表中搜索非拉丁字符

using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))using (Table table = geodatabase.OpenDataset<Table>("TableWithChineseCharacters"))
{// 错误的查询示例string incorrectWhereClause = "颜色 = '绿'";// 获取国家字符串前缀string nationalStringPrefix = "";SQLSyntax sqlSyntax = geodatabase.GetSQLSyntax();nationalStringPrefix = sqlSyntax.GetSupportedStrings(SQLStringType.NationalStringPrefix).First();// 正确的查询示例QueryFilter queryFilter = new QueryFilter(){WhereClause = "颜色 = " + nationalStringPrefix + "'绿'"};
}

3 使用一组对象 ID 搜索表

public RowCursor SearchingATable(Table table, IReadOnlyList<long> objectIDs)
{QueryFilter queryFilter = new QueryFilter(){ObjectIDs = objectIDs};return table.Search(queryFilter);
}

4 使用空间查询过滤器搜索要素类

public async Task SearchingAFeatureClass()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))using (FeatureClass schoolBoundaryFeatureClass = geodatabase.OpenDataset<FeatureClass>("LocalGovernment.GDB.SchoolBoundary")){// 使用空间查询过滤器SpatialQueryFilter spatialQueryFilter = new SpatialQueryFilter{WhereClause = "DISTRCTNAME = 'Indian Prairie School District 204'",FilterGeometry = new PolygonBuilderEx(new List<Coordinate2D>{new Coordinate2D(1021880, 1867396),new Coordinate2D(1028223, 1870705),new Coordinate2D(1031165, 1866844),new Coordinate2D(1025373, 1860501),new Coordinate2D(1021788, 1863810)}).ToGeometry(),SpatialRelationship = SpatialRelationship.Within};using (RowCursor indianPrairieCursor = schoolBoundaryFeatureClass.Search(spatialQueryFilter, false)){while (indianPrairieCursor.MoveNext()){using (Feature feature = (Feature)indianPrairieCursor.Current){// 处理要素Console.WriteLine(feature.GetObjectID());}}}}});
}

5 从表中选择行

public async Task SelectingRowsFromATable()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))using (Table enterpriseTable = geodatabase.OpenDataset<Table>("LocalGovernment.GDB.piCIPCost")){QueryFilter anotherQueryFilter = new QueryFilter { WhereClause = "FLOOR = 1 AND WING = 'E'" };// 选择所有匹配条目using (Selection anotherSelection = enterpriseTable.Select(anotherQueryFilter, SelectionType.ObjectID, SelectionOption.Normal)){}// 选择一个匹配条目using (Selection onlyOneSelection = enterpriseTable.Select(anotherQueryFilter, SelectionType.ObjectID, SelectionOption.OnlyOne)){}// 获取空选择集using (Selection emptySelection = enterpriseTable.Select(anotherQueryFilter, SelectionType.ObjectID, SelectionOption.Empty)){}// 选择表中所有记录using (Selection allRecordSelection = enterpriseTable.Select(null, SelectionType.ObjectID, SelectionOption.Normal)){}}});
}

6 从要素类中选择要素

public async Task SelectingFeaturesFromAFeatureClass()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))using (FeatureClass enterpriseFeatureClass = geodatabase.OpenDataset<FeatureClass>("LocalGovernment.GDB.FacilitySite")){List<Coordinate2D> newCoordinates = new List<Coordinate2D>{new Coordinate2D(1021570, 1880583),new Coordinate2D(1028730, 1880994),new Coordinate2D(1029718, 1875644),new Coordinate2D(1021405, 1875397)};SpatialQueryFilter spatialFilter = new SpatialQueryFilter{WhereClause = "FCODE = 'Park'",FilterGeometry = new PolygonBuilderEx(newCoordinates).ToGeometry(),SpatialRelationship = SpatialRelationship.Crosses};// 选择所有匹配条目using (Selection anotherSelection = enterpriseFeatureClass.Select(spatialFilter, SelectionType.ObjectID, SelectionOption.Normal)){}// 选择一个匹配条目using (Selection onlyOneSelection = enterpriseFeatureClass.Select(spatialFilter, SelectionType.ObjectID, SelectionOption.OnlyOne)){}// 获取空选择集using (Selection emptySelection = enterpriseFeatureClass.Select(spatialFilter, SelectionType.ObjectID, SelectionOption.Empty)){}// 选择表中所有记录using (Selection allRecordSelection = enterpriseFeatureClass.Select(null, SelectionType.ObjectID, SelectionOption.Normal)){}}});
}

7 获取表中当前有多少行的计数

// 调用需在 QueuedTask.Run() 内部
var table = featureLayer.GetTable();
var count = table.GetCount();

8 获取图层的特征计数

var lyr = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault();
QueuedTask.Run(() =>{FeatureClass featureClass = lyr.GetFeatureClass();long nCount = featureClass.GetCount();});

9 对表进行排序

public RowCursor SortWorldCities(FeatureClass worldCitiesTable)
{using (FeatureClassDefinition featureClassDefinition = worldCitiesTable.GetDefinition()){Field countryField = featureClassDefinition.GetFields().First(x => x.Name.Equals("COUNTRY_NAME"));Field cityNameField = featureClassDefinition.GetFields().First(x => x.Name.Equals("CITY_NAME"));// 创建国家字段的排序描述SortDescription countrySortDescription = new SortDescription(countryField);countrySortDescription.CaseSensitivity = CaseSensitivity.Insensitive;countrySortDescription.SortOrder = SortOrder.Ascending;// 创建城市字段的排序描述SortDescription citySortDescription = new SortDescription(cityNameField);citySortDescription.CaseSensitivity = CaseSensitivity.Insensitive;citySortDescription.SortOrder = SortOrder.Ascending;// 创建表排序描述TableSortDescription tableSortDescription = new TableSortDescription(new List<SortDescription>() { countrySortDescription, citySortDescription });return worldCitiesTable.Sort(tableSortDescription);}
}

10 计算表的统计信息

// 计算1990年和2000年人口字段的总和和平均值，并按区域分组和排序
public void CalculateStatistics(FeatureClass countryFeatureClass)
{using (FeatureClassDefinition featureClassDefinition = countryFeatureClass.GetDefinition()){// 获取字段Field regionField = featureClassDefinition.GetFields().First(x => x.Name.Equals("Region"));Field pop1990Field = featureClassDefinition.GetFields().First(x => x.Name.Equals("Pop1990"));Field pop2000Field = featureClassDefinition.GetFields().First(x => x.Name.Equals("Pop2000"));// 创建排序描述SortDescription regionSortDescription = new SortDescription(regionField);regionSortDescription.CaseSensitivity = CaseSensitivity.Insensitive;regionSortDescription.SortOrder = SortOrder.Ascending;TableSortDescription tableSortDescription = new TableSortDescription(new List<SortDescription>() { regionSortDescription });// 创建统计描述TableStatisticsDescription tableStatisticsDescription = new TableStatisticsDescription(new List<Field>() { pop1990Field, pop2000Field },new List<StatisticsFunction>() { StatisticsFunction.Sum, StatisticsFunction.Mean },new List<Field>() { regionField },tableSortDescription);// 计算统计信息using (StatisticsResult statisticsResult = countryFeatureClass.CalculateStatistics(tableStatisticsDescription)){foreach (StatisticsRecord record in statisticsResult){var region = record.GroupBy[0];var pop1990Sum = record[0];var pop1990Mean = record[1];var pop2000Sum = record[2];var pop2000Mean = record[3];}}}
}

11 在单个表上评估 QueryDef

public async Task SimpleQueryDef()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file")))){QueryDef adaCompliantParksQueryDef = new QueryDef{Tables = "Park",WhereClause = "ADACOMPLY = 'Yes'",};using (RowCursor rowCursor = geodatabase.Evaluate(adaCompliantParksQueryDef, false)){while (rowCursor.MoveNext()){using (Row row = rowCursor.Current){Feature feature = row as Feature;Geometry shape = feature.GetShape();String type = Convert.ToString(row["ADACOMPLY"]); // 每行都是 "Yes"try{Table table = row.GetTable(); // 总是抛出异常}catch (NotSupportedException exception){// 处理不支持的异常}}}}}});
}

12 使用 WHERE 子句计算连接上的 QueryDef

public async Task JoiningWithWhereQueryDef()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file")))){QueryDef municipalEmergencyFacilitiesQueryDef = new QueryDef{SubFields = "EmergencyFacility.OBJECTID, EmergencyFacility.Shape, EmergencyFacility.FACILITYID, FacilitySite.FACILITYID, FacilitySite.FCODE",Tables = "EmergencyFacility, FacilitySite",WhereClause = "EmergencyFacility.FACNAME = FacilitySite.NAME AND EmergencyFacility.JURISDICT = 'Municipal'",};using (RowCursor rowCursor = geodatabase.Evaluate(municipalEmergencyFacilitiesQueryDef, false)){while (rowCursor.MoveNext()){using (Row row = rowCursor.Current){Feature feature = row as Feature;Geometry shape = feature.GetShape();long objectID = Convert.ToInt64(row["EmergencyFacility.OBJECTID"]);String featureCode = Convert.ToString(row["FacilitySite.FCODE"]);IReadOnlyList<Field> fields = feature.GetFields(); // 每个子字段包含一个 ArcGIS.Core.Data.Field 对象}}}}});
}

13 在外部连接上计算 QueryDef

public async Task EvaluatingQueryDefWithOuterJoin()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file")))){QueryDef queryDefWithLeftOuterJoin = new QueryDef{Tables = "CommunityAddress LEFT OUTER JOIN MunicipalBoundary on CommunityAddress.Municipality = MunicipalBoundary.Name",SubFields = "CommunityAddress.OBJECTID, CommunityAddress.Shape, CommunityAddress.SITEADDID, CommunityAddress.ADDRNUM, CommunityAddress.FULLNAME, CommunityAddress.FULLADDR, CommunityAddress.MUNICIPALITY, MunicipalBoundary.Name, MunicipalBoundary.MUNITYP, MunicipalBoundary.LOCALFIPS",};using (RowCursor rowCursor = geodatabase.Evaluate(queryDefWithLeftOuterJoin, false)){while (rowCursor.MoveNext()){using (Row row = rowCursor.Current){Feature feature = row as Feature;Geometry shape = feature.GetShape();int siteAddressId = Convert.ToInt32(row["CommunityAddress.SITEADDID"]);String stateName = Convert.ToString(row["MunicipalBoundary.name"]);}}}}});
}

14 在内部连接上评估 QueryDef

public async Task EvaluatingQueryDefWithInnerJoin()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file")))){QueryDef queryDef = new QueryDef(){Tables = "People INNER JOIN States ON People.FK_STATE_ID = States.OBJECTID",SubFields = "People.OBJECTID, People.First_Name, People.Last_Name, People.City, States.State_Name"};using (RowCursor cursor = geodatabase.Evaluate(queryDef)){while (cursor.MoveNext()){using (Row row = cursor.Current){// 处理行}}}}});
}

15 在嵌套 - INNER 和 OUTER 连接上评估 QueryDef

public async Task EvaluatingQueryDefWithNestedJoin()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file")))){QueryDef queryDef = new QueryDef(){Tables = "((People INNER JOIN States ON People.FK_STATE_ID = States.OBJECTID) LEFT OUTER JOIN Homes ON People.OBJECTID = Homes.FK_People_ID)",SubFields = "People.OBJECTID, People.First_Name, People.Last_Name, States.State_Name, Homes.Address"};using (RowCursor cursor = geodatabase.Evaluate(queryDef, false)){while (cursor.MoveNext()){using (Row row = cursor.Current){// 处理行}}}}});
}

16 为数据库表创建默认查询描述并获取查询描述的 ArcGIS.Core.Data.Table

public async Task DefaultQueryDescription()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{DatabaseConnectionProperties databaseConnectionProperties = new DatabaseConnectionProperties(EnterpriseDatabaseType.SQLServer){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",Database = "database",User = "user",Password = "password"};using (Database database = new Database(databaseConnectionProperties)){QueryDescription queryDescription = database.GetQueryDescription("CUSTOMERS");using (Table table = database.OpenTable(queryDescription)){// 使用表}}});
}

17 从数据库表的自定义查询创建查询说明

public async Task CustomQueryDescription()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{DatabaseConnectionProperties databaseConnectionProperties = new DatabaseConnectionProperties(EnterpriseDatabaseType.SQLServer){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",Database = "database",User = "user",Password = "password"};using (Database database = new Database(databaseConnectionProperties)){QueryDescription queryDescription = database.GetQueryDescription("SELECT OBJECTID, Shape, FACILITYID FROM EmergencyFacility WHERE JURISDICT = 'Municipal'", "MunicipalEmergencyFacilities");using (Table table = database.OpenTable(queryDescription)){// 使用表.}}});
}

18 从没有不可为空的唯一 id 列的联接查询创建查询说明

public async Task JoinQueryDescription()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{DatabaseConnectionProperties databaseConnectionProperties = new DatabaseConnectionProperties(EnterpriseDatabaseType.SQLServer){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",Database = "database",User = "user",Password = "password"};using (Database database = new Database(databaseConnectionProperties)){QueryDescription queryDescription = database.GetQueryDescription("SELECT BUSLINES.ID as BUSLINESID, BUSSTOPS.ID as BUSSTOPSID, BUSLINES.RTE_DESC, BUSLINES.DIR, BUSSTOPS.JURISDIC, BUSSTOPS.LOCATION, BUSSTOPS.ROUTE,BUSSTOPS.SHAPE from demosql.dbo.BUSSTOPS JOIN demosql.dbo.BUSLINES ON BUSSTOPS.ROUTE = BUSLINES.ROUTE", "BusInfo");queryDescription.SetObjectIDFields("BUSLINESID,BUSSTOPSID");using (Table table = database.OpenTable(queryDescription)){// 使用表.}}});
}

19 从具有多个形状类型的数据库表的查询创建查询说明

public async Task MultiGeometryQueryDescription()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{DatabaseConnectionProperties databaseConnectionProperties = new DatabaseConnectionProperties(EnterpriseDatabaseType.SQLServer){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",Database = "database",User = "user",Password = "password"};using (Database database = new Database(databaseConnectionProperties)){QueryDescription pointQueryDescription = database.GetQueryDescription("SELECT * FROM POINTS", "PointLayer");QueryDescription lineQueryDescription = database.GetQueryDescription("SELECT * FROM LINES", "LineLayer");using (Table pointTable = database.OpenTable(pointQueryDescription)){// 使用点表.}using (Table lineTable = database.OpenTable(lineQueryDescription)){// 使用线表.}}});
}

20 从 SQLite 数据库表的查询创建查询说明

public async Task SqliteQueryDescription()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Database database = new Database(new SQLiteConnectionPath(new Uri("Path\\To\\Sqlite\\Database\\USA.sqlite")))){QueryDescription washingtonCitiesQueryDescription = database.GetQueryDescription("select OBJECTID, Shape, CITY_FIPS, CITY_NAME, STATE_FIPS, STATE_CITY, TYPE, CAPITAL from main.cities where STATE_NAME='Washington'", "WashingtonCities");using (Table washingtonTable = database.OpenTable(washingtonCitiesQueryDescription)){// 使用washingtonTable。}}});
}

21 使用 SQLSyntax 形成与平台无关的查询

public async Task UsingSqlSyntaxToFormPlatformAgnosticQueries()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("C:\\Data\\LocalGovernment.gdb"))))using (FeatureClass featureClass = geodatabase.OpenDataset<FeatureClass>("FacilitySite")){SQLSyntax sqlSyntax = geodatabase.GetSQLSyntax();string substringFunctionName = sqlSyntax.GetFunctionName(SQLFunction.Substring);string upperFunctionName = sqlSyntax.GetFunctionName(SQLFunction.Upper);string substringfunction = string.Format("{0}({1}(FCODE, 1, 6)) = 'SCHOOL'", upperFunctionName, substringFunctionName);QueryFilter queryFilter = new QueryFilter{WhereClause = substringfunction};using (Selection selection = featureClass.Select(queryFilter, SelectionType.ObjectID, SelectionOption.Normal)){// 使用选择结果。}}});
}

22 将文件地理数据库要素类连接到具有虚拟关系类的 Oracle 数据库查询图层要素类

public async Task JoiningFileGeodatabaseFeatureClassToOracleQueryLayer()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase geodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("C:\\Data\\LocalGovernment.gdb"))))using (Database database = new Database(new DatabaseConnectionProperties(EnterpriseDatabaseType.Oracle){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",User = "user",Password = "password",Database = "database"}))using (FeatureClass leftFeatureClass = geodatabase.OpenDataset<FeatureClass>("Hospital"))using (Table rightTable = database.OpenTable(database.GetQueryDescription("FacilitySite"))){Field originPrimaryKey = leftFeatureClass.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("facilityId"));Field destinationForeignKey = rightTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("hospitalID"));VirtualRelationshipClassDescription description = new VirtualRelationshipClassDescription(originPrimaryKey, destinationForeignKey, RelationshipCardinality.OneToOne);using (RelationshipClass relationshipClass = leftFeatureClass.RelateTo(rightTable, description)){JoinDescription joinDescription = new JoinDescription(relationshipClass){JoinDirection = JoinDirection.Forward,JoinType = JoinType.LeftOuterJoin};Join join = new Join(joinDescription);using (Table joinedTable = join.GetJoinedTable()){// 对连接后的表执行操作。}}}});
}

23 连接来自不同地理数据库的两个表

public async Task JoinTablesFromDifferentGeodatabases()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{using (Geodatabase sourceGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("Path \\ to \\Geodatabase \\ one"))))using (Geodatabase destinationGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri("Path \\ to \\Geodatabase \\ two"))))using (Table sourceTable = sourceGeodatabase.OpenDataset<Table>("State"))using (Table destinationTable = destinationGeodatabase.OpenDataset<Table>("Cities")){Field primaryKeyField = sourceTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("State.State_Abbreviation"));Field foreignKeyField = destinationTable.GetDefinition().GetFields().FirstOrDefault(field => field.Name.Equals("Cities.State"));VirtualRelationshipClassDescription virtualRelationshipClassDescription = new VirtualRelationshipClassDescription(primaryKeyField, foreignKeyField, RelationshipCardinality.OneToMany);using (RelationshipClass relationshipClass = sourceTable.RelateTo(destinationTable, virtualRelationshipClassDescription)){JoinDescription joinDescription = new JoinDescription(relationshipClass){JoinDirection = JoinDirection.Forward,JoinType = JoinType.InnerJoin,TargetFields = sourceTable.GetDefinition().GetFields()};using (Join join = new Join(joinDescription)){Table joinedTable = join.GetJoinedTable();//处理连接后的表。例如 ..using (RowCursor cursor = joinedTable.Search()){while (cursor.MoveNext()){using (Row row = cursor.Current){// 使用行数据。}}}}}}});
}

24 使用在地理数据库中连接两个版本化表的查询创建查询表

public async Task QueryTableJoinWithVersionedData()
{await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>{QueryDef queryDef = new QueryDef{Tables = "CommunityAddress JOIN MunicipalBoundary on CommunityAddress.Municipality = MunicipalBoundary.Name",SubFields = "CommunityAddress.OBJECTID, CommunityAddress.Shape, CommunityAddress.SITEADDID, CommunityAddress.ADDRNUM, CommunityAddress.FULLNAME, CommunityAddress.FULLADDR, CommunityAddress.MUNICIPALITY, MunicipalBoundary.Name, MunicipalBoundary.MUNITYP, MunicipalBoundary.LOCALFIPS",};using (Geodatabase testVersion1Geodatabase = new Geodatabase(new DatabaseConnectionProperties(EnterpriseDatabaseType.Oracle){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",User = "user",Password = "password",Database = "database",Version = "user.testVersion1"})){QueryTableDescription queryTableDescription = new QueryTableDescription(queryDef){Name = "CommunityAddrJounMunicipalBoundr",PrimaryKeys = testVersion1Geodatabase.GetSQLSyntax().QualifyColumnName("CommunityAddress", "OBJECTID")};// 将基于testVersion1。using (Table queryTable = testVersion1Geodatabase.OpenQueryTable(queryTableDescription)){// 使用queryTable。}}using (Geodatabase testVersion2Geodatabase = new Geodatabase(new DatabaseConnectionProperties(EnterpriseDatabaseType.Oracle){AuthenticationMode = AuthenticationMode.DBMS,Instance = "instance",User = "user",Password = "password",Database = "database",Version = "user.testVersion2"})){QueryTableDescription queryTableDescription = new QueryTableDescription(queryDef){Name = "CommunityAddrJounMunicipalBoundr",PrimaryKeys = testVersion2Geodatabase.GetSQLSyntax().QualifyColumnName("CommunityAddress", "OBJECTID")};// 将基于testVersion2。using (Table queryTable = testVersion2Geodatabase.OpenQueryTable(queryTableDescription)){// 使用queryTable。}}});
}

25 检查字段值是否为空

var val = row[field.Name];
if (val is DBNull || val == null)
{// 字段值为空
}
else
{// 字段值不为空
}

26 从字段中获取域字符串

public string GetDomainStringFromField(Row row, Field field)
{// 从Row中获取表和表定义using (Table table = row.GetTable())using (TableDefinition tableDefinition = table.GetDefinition()){// 获取子类型字段的名称string subtypeFieldName = tableDefinition.GetSubtypeField();// 获取子类型，如果有的话Subtype subtype = null;if (subtypeFieldName.Length != 0){// 获取此行的子类型字段的值var varSubtypeCode = row[subtypeFieldName];long subtypeCode = (long)varSubtypeCode;// 获取此行的子类型subtype = tableDefinition.GetSubtypes().First(x => x.GetCode() == subtypeCode);}// 获取此字段的编码值域CodedValueDomain domain = field.GetDomain(subtype) as CodedValueDomain;// 返回此字段的文本字符串if (domain != null){return domain.GetName(row[field.Name]);}else{return row[field.Name].ToString();}}
}