Deferred LINQ Query Execution

Queries defined with LINQ in MYOB Acumatica Framework implement the IQueryable interface—that is, for these queries, the system generates expression trees and executes the queries only when they are iterated over. For details about query execution, see Data Query Execution.

Execution of the LINQ Query in Code

To execute the query, you do one of the following:

Call the ToList or ToArray method for the query, as shown in the following code.
```
//query is a LINQ expression.
var data = query.ToList();
```

Iterate the query by using the foreach statement, as shown in the following code.

//query has the IQueryable<Product> type.
//Product is a DAC.
foreach (Product record in query)
{
    ...
}

Explicit Merge of Records with PXCache

The system merges with PXCache the records the system has retrieved from the database by using the LINQ queries, as described in Merge of the Records with PXCache.

You may need to explicitly merge the records retrieved from the database with a particular PXCache object. To merge the records with PXCache explicitly, you use the Merge method, as shown in the following code example.

ProductMaint graph = PXGraph.CreateInstance<ProductMaint>();
var query = new PXSelectReadonly<Product>(graph).Select()
    .Select(r => r.GetItem<Product>())
    .Where(p => SQL.Like(p.ProductName, "%d%") && p.StockUnit != null)
    .OrderBy(p => p.ProductID);
var result = query.Merge(p => p).ToArray();

You also can specify that the query should not be merged with PXCache by using the ReadOnly method, as shown in the following code example.

ProductMaint graph = PXGraph.CreateInstance<ProductMaint>();
var query = new PXSelect<Product>(graph).Select()
    .Select(r => r.GetItem<Product>())
    .Where(p => SQL.Like(p.ProductName, "%d%") && p.StockUnit != null);
    .OrderBy(p => p.ProductID);
var result = query.ReadOnly().ToArray();