GetQueryDescription(String,String) Method

In This Topic

Gets the QueryDescription object associated with the query layer that is created from one or more database table(s) as specified by . This method must be called on the MCT. Use QueuedTask.Run.

Syntax

C#
Visual Basic (Declaration)

public QueryDescription GetQueryDescription( 
   string queryStatement,
   string queryLayerName
)

Public Overloads Function GetQueryDescription( _
   ByVal queryStatement As String, _
   ByVal queryLayerName As String _
) As QueryDescription

Parameters

queryStatement: A valid SQL SELECT statement that describes how the query layer should be created.
queryLayerName: A given name.

Return Value

The QueryDescription object that fully describes how the underlying database table(s) that make up the query layer should be represented as a Table or FeatureClass if the query layer is spatially enabled.

Exceptions

Exception	Description
System.ArgumentException	queryStatement or queryLayerName is null or an empty string.
ArcGIS.Core.Data.Exceptions.GeodatabaseException	A database-related exception has occurred.

Remarks

A QueryDescription object fully describes how a single database table or one or more database tables (specified by a valid SQL SELECT statement) should be represented as a Table or FeatureClass if the table is spatially enabled. Essentially, there are two flavors of QueryDescription. The first is created by this method. Given a valid SQL SELECT statement and a query layer name, it encapsulates all the important properties that describe the underlying query layer that is created from one or more tables (i.e., QueryDescription.IsQueryLayer returns true). The second flavor is created by GetQueryDescription(String). Given a table name (fully qualified or unqualified), it encapsulates all the important properties that describe the underlying single table (i.e., QueryDescription.IsQueryLayer returns false).

Example

Create QueryDescription from a custom query for a Database table

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))
      {
        // Use the table.
      }
    }
  });
}

Create QueryDescription from a join query where there is no non-nullable unique id column

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))
      {
        // Use the table.
      }
    }
  });
}

Create QueryDescription from a query for a Database table which has more than one shape type

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 Description, SHAPE, UniqueID from MULTIGEOMETRYTEST", "MultiGeometryPoint");
      pointQueryDescription.SetShapeType(GeometryType.Point);
      using (Table pointTable = database.OpenTable(pointQueryDescription))
      {
        //use pointTable
      }

      QueryDescription polygonQueryDescription = database.GetQueryDescription("select Description, SHAPE, UniqueID from MULTIGEOMETRYTEST", "MultiGeometryPolygon");
      polygonQueryDescription.SetShapeType(GeometryType.Polygon);
      using (Table polygonTable = database.OpenTable(polygonQueryDescription))
      {
        //use polygonTable
      }
    }
  });
}

Create QueryDescription from a query for an SQLite Database table

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))
      {
        // Use washingtonTable.
      }
    }
  });
}

Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

Reference

Database Class
Database Members
Overload List

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