When you add a dataset as a layer to a map or scene,
sometimes you only want to work with and draw a subset of the features in the dataset. Examples include the following:
-
From a dataset of world cities, working with only those with a population greater than 1 million
-
From a dataset of hydrology lines, working with only perennial streams
-
From a dataset of parcels, working with only those that are zoned commercial
Definition queries allow you to define a subset of features to work with in a layer by filtering which features are retrieved from the dataset by the layer. This means that a definition query affects not only drawing, but also which features appear in the layer's attribute table and can be selected, labeled, identified, and processed by geoprocessing tools.
If you want to limit which features are drawn but retain all features from querying and processing, consider using
display filters
instead. Definition queries and display filters can be used together on a layer, but definition queries limit the features available in the layer, while display filters only limit which features are displayed.
Definition queries are composed of one or more clauses. They are written in SQL syntax, constructed using the query builder. See
Introduction to query expressions
to learn how to work with clauses and queries and how to save and load queries from files.
A layer can have multiple definition queries associated with it, but only one definition query can be active at a time. Even with multiple definition queries defined for a layer, all can be inactive so that no definition query is applied.
This topic outlines definition queries on a feature layer, but definition queries can be used in the same way on
stand-alone tables
.
Create a definition query
for a layer
To create a definition query on a layer, follow these steps:
-
Ensure a layer is selected in the
Contents
pane.
-
On the
Feature Layer
tab set, click the
Data
tab.
-
On the
Data
tab, in the
Definition Query
group, click the
Build Definition Query
button
to open the
Layer Properties
dialog box with its
Definition Query
tab open.
-
Click the
New definition query
button, or click its drop-down menu to create a new query in clause mode, SQL mode, or a query expression file
(.exp)
.
-
In the query builder, choose values from the menus to construct the clause. These menus and their values are specific to the underlying source data.
-
Optionally, click
Add Clause
to add another clause to the query. Choose values from the menus in the new clause as required. Repeat this step to add additional clauses as necessary.
-
Optionally, click
Field settings
to modify the display of the field values. These settings are applied to all clauses.
-
Show field aliases
is selected by default. Click
Show field names
to include the name of the table in the clause's field drop-down menu. This is especially helpful if your layer participates in a join that shares common field names.
-
Click
Sort Ascending
or
Sort Descending
to display the names of the fields in the drop-down menu in alphabetical order. Click
Original order
to return the fields to their default order.
-
Show visible fields
is selected by default. Click
Show all fields
to display hidden fields in the clause's field drop-down menu.
-
Show domain and subtype values only
is selected by default. Click
Show all values
to include any invalid or incorrect values in the field's drop-down menu of unique values.
-
Optionally, hover over the query name and click to rename it.
-
Optionally, click
Verify the SQL expression is valid
to verify the query.
-
To verify and finalize the query, in the query builder, click
Apply
.
-
If this is the only definition query on the layer, it becomes the active definition query, and is immediately applied. If there are other definition queries on the layer, click
Set as Active
to apply a
definition
query to the layer.
Set the active definition query
You can define more than one definition query for a layer or table, and switch between them. Only one is active at any time, or you can have no queries active. The definition queries are stored as a property of the layer.
To switch between active definition queries, follow these steps:
-
Ensure that a layer is selected in the
Contents
pane.
-
On the
Feature Layer
tab set, click the
Data
tab.
-
On the
Data
tab, in the
Definition Query
group, choose a query from the
Definition Query
menu to apply to the layer.
-
Alternatively, you can set the active query from the
Definition Query
tab of the
Layer Properties
dialog box.
-
Click
Set as Active
and click
Apply
to apply that query to the layer. Any other queries become inactive. The active query is named at the bottom of the
Properties
dialog box. If you have many queries listed and the active query is out of view, click
Show the active definition query
to scroll to it.
-
Click
Clear active query
and click
Apply
to have no query applied to the layer or table. All queries are retained by the layer or table, but none of them are currently applied.
Modify existing queries
With the layer selected in the
Contents
pane, in the
Feature Layer
tab set, on the
Data
tab, in the
Definition Query
group, click the
Build Definition Query
button
to open the
Layer Properties
dialog box with its
Definition Query
tab open. To modify a definition query, hover over the query and follow any of these actions:
Set definition queries on multiple layers at once
If multiple layers share definition queries with a common name, even if the content of the queries is not the same, the queries can be activated for the layers simultaneously. This means you can construct a number of related queries for a certain scenario and apply them all at once. You can then switch to a different set of queries to satisfy a different scenario, if necessary.
To apply definition queries with a common name to multiple layers simultaneously, follow these steps:
-
Ensure the layers are selected in the
Contents
pane.
-
On the
Feature Layer
tab set, click the
Data
tab.
-
On the
Data
tab, in the
Definition Query
group, choose a query from the
Definition Query
menu to apply to the layer.
Only definition queries with a name common to all selected layers are shown.
Automate definition query creation
You can automate the creation and execution of definition queries with
Python
by using a combination of ArcPy functions. For information on this topic, including code samples, see the
Layer
class documentation.
Sharing layers with definition queries
When a layer is shared as a feature layer or within a map image layer, only the active definition query is retained and honored. All other inactive definition queries are dropped.
.
.
.