Query Elements in the AOT

Artykuł
05/18/2015

Applies To: Microsoft Dynamics AX 2012 R3, Microsoft Dynamics AX 2012 R2, Microsoft Dynamics AX 2012 Feature Pack, Microsoft Dynamics AX 2012

Static queries are pre-defined queries that can be accessed from the Application Object Tree (AOT). In Microsoft Dynamics AX, static queries are located in the Queries node and contain the following primary subnodes:

Methods
Data Sources
Dependent Objects
Composite Query

Each Data Sources node has the following subnodes:

Fields
Ranges
Data Sources
Group By
Order By
Relations (only present in a child data source)

Methods

The Methods node displays all the methods available from a query. In this node you can add a new method to a query. You can also override methods on the QueryRun system class and add your own code to class methods inherited from the QueryRun class. Only new methods and overridden methods appear in the Queries node except for the classDeclaration method which is always present.

To add a new method:

Navigate to the Queries node in the AOT, right-click the node and, then select New Method.
Enter your code in the Editor window and save your changes.

To override a method:

Navigate to the Queries node in the AOT, right-click the node, and then select Override Method.
Select the method that you want to override.
Enter your code in the Editor window and save your changes.

Methods that have been overridden display an icon with an arrow.

Data Sources

The Data Sources node contains a hierarchy of data sources from which the query gets its data. A query data source can be a table, map, or view.

Data sources can be embedded inside each other (nested). A nested data source is referred to as a child data source of the parent data source. A child data source has all the standard data source elements, and it also contains a relations element. The relation is used to define how the parent data source is related to the child data source. Whenever a record in the parent data source is selected, the child records are selected based on the relation that is defined and any record ranges that are specified.

If there is more than one data source at the same level, the query accesses the data sources sequentially and fetches the records from each of them.

Fields

The Fields node contains the data elements returned by the table, map, or view. If you set the Fields node Dynamic property to Yes, all the fields in the data source are returned. If you set the Dynamic property to No, you can right-click a field and select Delete to remove it from the data source.

The Fields node enables you to add an aggregate field based on a field in the source table, map, or view. The aggregate functions that are available are AVG, SUM, COUNT, MIN, or MAX.

Ranges

The Ranges node contains ranges that limit the number of records returned by the query to only those that match the range expression. The Field property of the Range defines the field that participates in the range expression. The Value property of the Range contains the expression that defines the conditions to be met by the records returned by the data source.

For example, you can limit the number of records that are return by a query against the CustTable table. You can limit the returned rows to those that contain specific AccountNum values. The following shows the defined range expression.

..5000, 5012..5014, 5500, !6500, 6000..

This range expression retrieves:

Records with AccountNum values less than or equal to 5000.
Records with AccountNum values from 5012 to 5014 inclusive.
Records with the AccountNum equal to 5500.
Records with AccountNum values above 6000, except for any records with the AccountNum equal to 6500.

Range expressions on different fields are combined by using the AND expression. Range expressions on the same field are combined by using the OR expression. The following table lists the operators and symbols that can be used in range expressions.

Symbol	Meaning	Example	Description
=	Equal to	=Smith	Finds Smith.
!	Not equal to	!Smith	Finds all values except Smith.
..	Between two values	A..C	Finds all records from A to C including records with A and C.
>	Greater than	>1000	Finds all values greater than 1000.
<	Less than	<1000	Finds all values less than 1000 including negative values.
*	Match values that contain the characters before or after the asterisk	S* or east	Finds all values that begin with the letter S. Finds all values that include the word east.
?	Matches a single unknown character	Sm?th	Finds all values that include only the letters s, m, t, and h in the order shown and any character in the ? placeholder
,	Separates expression components	A..D, !C	Finds A, B, and D.

Note

Complex range expressions can affect performance. The more filter expressions Microsoft Dynamics AX must apply to the data the longer the query will take to run.

Ranges can also be defined in dynamic queries using X++. For more information, see expressions in query ranges.

Group By

You use the Group By node to restrict the field combination listed to only the unique value combinations in their data. The other fields in the query must all be processed by aggregate functions.

For example, in your query of the table CustTrans you could list the columns AccountNum and TransType under Group By. This would ensure that the retrieved data would not include the value combination of 4004 and Purch more than one time. The column AmountCur could be a sum of every AmountCur from every database row that had the value pair of 4004 and Purch.

Order By

The Order By node contains the sort order for the data source. Sort order is defined on a field or index in the table, map, or view on which the data source is based. Therefore, you can sort the query results on a field that is in the table whether that field is returned by the query (listed in the Fields node). A query can be sorted on multiple fields in ascending or descending order.

If the query data source is a table, an index can be specified in the Sorting node. When an index is specified as the sort order for a query, the query does not create a new index but rather uses the sort order in an existing table index.

Note

Sorting can affect performance. For example if a sort is defined on a long string field, the query returns a large data set. To improve performance, sort on numeric or indexed fields. If you must sort on a long string field such as CustName, limit the number of records returned by the query by using a range.

Relations

The Relations node contains the group of relation properties that define a join between the child data source and another data source in the query. To create joins between data sources, add one or more groups of relation properties to the Relations node. The Relations node is only found in a child data source. For more information about how to add a relation, see How to: Add Multiple Data Sources to a Query.

The JoinMode property on the child data source indicates the type of join that exists between a parent data source and a child data source. The options for the JoinMode property are InnerJoin, OuterJoin, ExistsJoin, or NoExistsJoin. For more information about how to set the JoinMode property, see How to: Add Multiple Data Sources to a Query.

To specify the data sources and data fields to use in the join, use the AOT to right-click the Relations node of a child data source, and then click New Relation. There are two methods for defining a relation between data sources:

Use the relation that is automatically created. By default, each child data source's underlying table, map, or view has a Relations property that is set to Yes. When this property is set to Yes, Microsoft Dynamics AX automatically adds a relation from the child data source to the parent data source. In this case, if there is an existing table relation between the two tables, the new relation is based on the existing table relation. If there is no existing table relation, the new relation is created based on an existing relation on an extended data type.

For example, the SalesQuotationUpdate query has a data source of the SalesQuotationTable. This data source has a child data source of table SalesQuotationLine. When a relation is created automatically for these two tables, it occurs through an existing table relation on the SalesQuotationLine table. The SalesQuotationLine table has a child data source of the InventDim table. When a relation is created automatically for these two tables, it is based on the existing relation on the extended data type InventDimId.

Use the AOT to specify the value of each relation property. Set property values that identify the fields and data sources to use to create the join. When the query executes, the values of the relation properties together with the JoinMode property value determine how the field data from one data source is used to retrieve data from the other data source. To define a join, set the value of the following properties.

Property	Description
CurrentDataSource	Specifies the name of the current child data source. You cannot change the value of this property.
Field	Select the field from the join data source to use in the join. When the query executes, the join uses the data value in this field to identify child data source records that have the same data value in the field specified by the RelatedField property.
JoinDataSource	Select the data source that you want to join with the current data source. The drop-down list displays the available data sources in the query. When you click a data source, you specify the parent data source of the join.
RelatedField	Select the field from the current data source to use in the join. When the query executes, the join uses the data values from this field and the Field property to match child data source records to parent data source records.

Dependent Objects

The Dependent Objects node contains a node for every AOT object that references the query, such as forms and reports. This shows you which objects are affected when you modify the query.

Composite Query

A query can be based on another query, as a mechanism for efficient reuse of the original query. You drop the original query onto this node, instead of onto the Data Sources node.

For more information, see Query Reuse by Composite Queries.

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