Summary
Creates a query layer from a DBMS table based on an input SQL select statement.
Usage
Query layers will only work with enterprise databases. File geodatabases are not a valid input workspace for this tool.
The layer that is created by the tool is temporary and will not persist after the session ends unless the project is saved or the data is persisted by making a copy using Copy Rows or Copy Features.
If the result of the SQL query entered returns a spatial column, the output will be a feature layer. If the SQL query does not return a spatial column, the output will be a stand-alone table.
The connection files necessary for this tool can be created using the Create Database Connection tool.
If the result of the SQL query does not return any rows, the output query layer will be empty, only containing the schema of the columns returned by the query. In this case, if the columns returned contain a spatial column, the tool will use the following defaults to create the query layer:
- Geometry type—POINT
- SRID—1
- Spatial Reference—NAD1983
Then you need to determine whether any of these values should be changed before executing the tool.
For geographic data, each record in the result returned from the SQL statement should have an associated spatial reference identifier (SRID). The SRID value is used by the database to determine the spatial reference for the data. The specific functional differences for the SRID will vary between each DBMS platform. Some DBMS platforms support multiple SRID values within the same table; ArcGIS only supports one value. This tool allows you to choose the SRID value or it will default to the SRID from the first record in the result set.
Syntax
arcpy.management.MakeQueryLayer(input_database, out_layer_name, query, {oid_fields}, {shape_type}, {srid}, {spatial_reference}, {spatial_properties}, {m_values}, {z_values}, {extent})| Parameter | Explanation | Data Type |
input_database | The database connection file that contains the data to be queried. | Workspace |
out_layer_name | The output name of the feature layer or table view to be created. | String |
query | The SQL statement that defines the select query to be issued to the database. | String |
oid_fields [oid_fields,...] (Optional) | One or more fields from the SELECT statement SELECT list that will generate a dynamic, unique row identifier. | String |
shape_type (Optional) | Specifies the shape type of the query layer. Only those records from the result set of the query that match the specified shape type will be used in the output query layer. Tool validation will attempt to set this property based on the first record in the result set. This can be changed before executing the tool if it is not the desired output shape type. This parameter is ignored if the result set of the query does not return a geometry field.
| String |
srid (Optional) | The spatial reference identifier (SRID) value for queries that return geometry. Only those records from the result set of the query that match the specified SRID value will be used in the output query layer. Tool validation will attempt to set this property based on the first record in the result set. This can be changed before executing the tool if it is not the desired output SRID value. This parameter is ignored if the result set of the query does not return a geometry field. | String |
spatial_reference (Optional) | The coordinate system that will be used by the output query layer. Tool validation will attempt to set this property based on the first record in the result set. This can be changed before executing the tool if it is not the desired output coordinate system. This parameter is ignored if the result set of the query does not return a geometry field. | Spatial Reference |
spatial_properties (Optional) | Specifies how the spatial properties for the layer will be defined. During the validation process, dimensionality, geometry type, spatial reference, SRID, and unique identifier properties will be set on the query layer. These values are based on the first row returned in the query. To manually define these properties instead of the tool querying the table to get them, use the default value for this parameter.
| Boolean |
m_values (Optional) | Specifies whether the layer will have m-values.
| Boolean |
z_values (Optional) | Specifies whether the layer will have z-values.
| Boolean |
extent (Optional) | The extent of the layer. This parameter is only used if Define spatial properties for the layer is checked (spatial_properties = DEFINE_SPATIAL_PROPERTIES in Python). The extent must include all features in the table.
| Extent |
Derived Output
| Name | Explanation | Data Type |
| out_layer | The output query layer. | Table View |
Code sample
The following Python window script demonstrates how to use the MakeQueryLayer tool in immediate mode.
import arcpy
sr = arcpy.SpatialReference("WGS 1984 UTM Zone 12N")
arcpy.MakeQueryLayer_management("Connections/moab.sde",
"Slickrock",
"select * from moabtrails where name = 'slickrock'",
"OBJECTID",
"POLYLINE",
"32611",
sr)The following stand-alone script demonstrates how to use the MakeQueryLayer tool.
# Name: MakeQueryLayer.py
# Description: Creates an output query layer based on a where clause.
# This example shows how to create a spatial reference object using the
# name of a coordinate system. It also demonstrates how to use two fields
# to generate a dynamic unique row identifier for the query layer.
# Import system modules
import arcpy
# Create the spatial reference for the output layer.
sr = arcpy.SpatialReference("WGS 1984 UTM Zone 12N")
# Run the tool
arcpy.MakeQueryLayer_management("Connections/moab.sde",
"Single Track",
"select * from moabtrails where type = 'single'",
"UID;name",
"POLYLINE",
"32611",
sr)Environments
Licensing information
- Basic: Yes
- Standard: Yes
- Advanced: Yes