Definition Query Arcgis

The unequalled operator () can also be used when querying strings. This topic describes how to create basic WHERE clause expressions, and is useful if you are new to SQL. For a more detailed reference, see SQL reference for query expressions used in ArcGIS. Queries are used to find and select a subset of tabular entities and records. All query expressions in ArcGIS Pro use Structured Query Language (SQL) to formulate these search specifications. Only entity templates whose default attribute values match the definition query are displayed. As I prepared to write this article, I spent some time reviewing technical support cases and forum posts about feature templates and definition queries. I discovered a common misconception that deleting a definition query is the only way to display a feature template in the Create Features window. In fact, a feature template appears in the Create Features window if the template`s default attribute values match the definition query. If the default attribute values do not satisfy the query, the feature model is hidden because the new feature disappears from the map once created.

You can define multiple definition queries for a layer or table and switch between them. Only one is active at any given time, or you can`t have active queries. Definition queries are stored as a property of the layer. Definition queries allow you to define a subset of the features to use in a layer by filtering the features retrieved from the layer from the dataset. This means that a definition query affects not only the drawing, but also the features that appear in the layer attribute table and can be selected, labeled, identified, and processed by geoprocessing tools. For more information, see SQL reference for query expressions used in ArcGIS. I shouldn`t try this workflow in my own fields either. For example, if I have a similar definition query where a field called Flow Length must be greater than 1000 meters, I must set 1000 or higher as the default attribute value of the feature model so that the new features appear on the map and feature model in the Create Features window. Therefore, each new stream I create is assigned a constant value of 1000 meters for the Flow Length field that is not the actual length of the entity. I should then recalculate the Feed Length field after creating each feature. Definition queries during editing work better for discrete categories rather than trying to set up an inequality equation like this.

You can automate the creation and execution of definition queries using Python using a combination of ArcPy functions. For more information about this topic, including code examples, see the documentation for the Layer class. Strings in expressions are case-sensitive unless you query feature classes and personal geodatabase tables. To perform a case-insensitive search in other data formats, you can use a SQL function to convert all values to the same case. For file-based data sources, such as file geodatabases or shapefiles, use the UPPER or LOWER function. Although disabling a layer is one of the most obvious reasons why feature models do not appear in the Create Features window, layer definition queries can be subtle causes. A definition query displays only the subset of entities that correspond to an attribute query defined in the Layer Properties dialog box. The remaining features are not drawn on the map or displayed in the Attributes table. Most ArcGIS dialog boxes in which you create a query expression specify the name of the layer or table that is right for you (or select it from a drop-down list). For example, feature templates can be created for all layers, even if there is a definition query. ArcMap always automatically creates feature models that match the icons of all layers when I first start an update session in a map, whether or not the layer has a definition query. Although an entity model does not appear in the Create Features window, it does not mean that it does not exist for the layer.

To view all the models on the map, I can open the Organize Feature Templates dialog box and click a layer in the list. If the entity model really doesn`t exist, I can also create a new template for a layer with a definition query using the Create New Templates Wizard. This topic describes definition queries for a feature layer, but definition queries can be used in the same way for stand-alone tables. If you want to use the same definition query for all feature layers, you can define and copy the definition query once and paste it into the Multiple Definition Queries (Enabled Items) text box. Select the check boxes next to the layers to which you want to apply the same definition query, and then click Replace. The specified definition query is now applied to each of the committed layers. Click OK to close the Overridden Definition Requests message. Another approach is to create a second stream layer that displays only intermittent streams, so that I can keep the original layer`s multi-year stream definition query intact. Anyway, the main thing is that I have to display the intermittent streams and also display the multi-year feeds so that I can create features that are related to them. The Definition Queries tab appears. The layers for which the definition queries were saved are bold after you save the query set.

Query Builder is used to create queries in many places, including the following: A subquery is a query nested within another query and supported only by geodatabase data sources. It can be used to apply predicate or aggregation functions, or to compare data to values stored in another table. For example, this query would select only countries that are not also listed in Table indep_countries: Definition queries in any field can affect the visibility of feature templates. Filtering feature models from the Create Features window can occur when the definition query is applied to any field in the layer, not just the field used for symbology. Later, I modify the Routes layer definition query to show only roads that are primary roads AND that are managed by the county. At this point, even my original template for main street functions disappears from the Create Features window. Sometimes, deleting a definition query is the best way to view an entity template. In the same map, I want to create a new intermittent stream feature. There are two templates (one for Evergreen and one for Intermittent) in the Organize Feature Templates dialog box, but the multi-year template appears only in the Create Features window. This reminds me that I use a definition query to show only multi-year feeds and hide smaller intermittent streams. I applied this definition query earlier to reduce the number of features displayed and declutter the map when working with a large area.

While the default attribute value of the entity template satisfies the route type part of the query, the value of the maintenance field does not. Therefore, I need to update the default attribute value of the maintenance field. To do this, in the Create Features window, I click the Organize Templates button to open the Organize Feature Templates dialog box, click the route layer name, open the Properties of the Main Roads template, and set the maintenance value to County. I could also copy the Main Routes template and create a new template specifically for these default attribute values. Definition queries consist of one or more clauses. They are written in SQL syntax and created using the query builder. See Introduction to Query Expressions to learn how to use clauses and queries, and how to store and load queries from files.