Add domain models and review OQL documentation

Author: MarkvanMents

content/en/docs/refguide/modeling/domain-model/oql/oql-clauses.md

@@ -38,6 +38,10 @@ Clauses must be presented in the following order, but can be left out if they ar
 
 The `UNION` clause defies the usual order presented above. It will be presented in a [Union Clause](#oql-union) section at the end.
 
+The domain model used in the various examples is shown below:
+
+{{< figure src="/attachments/refguide/modeling/domain-model/oql/oql-clauses-domain-model.png" >}}
+
 ## `SELECT` Clause {#select}
 
 The `SELECT` clause specifies which entity attributes or other specified data must be retrieved. The clause returns all the requested values of objects which match the `SELECT` clause.
@@ -111,15 +115,15 @@ The following query returns all attributes of objects of `Sales.Request` that ar
 ```
 SELECT Sales.Request/*
 FROM Sales.Customer
-JOIN Sales.Customer/Sales.Customer_Request/Sales.Request
+JOIN Sales.Customer/Sales.Request_Customer/Sales.Request
 ```
 
 The following query is equivalent to the previous one, but it uses table aliases
 
 ```
 SELECT Req/*
 FROM Sales.Customer Cust
-JOIN Cust/Sales.Customer_Request/Sales.Request Req
+JOIN Cust/Sales.Request_Customer/Sales.Request Req
 ```
 
 ### Selecting Distinct Values with `DISTINCT` {#distinct}
@@ -978,7 +982,7 @@ In the example below `Sales.Customer` object for Jim Elk does not have any assoc
 ```sql
 SELECT LastName
 FROM Sales.Customer
-ORDER BY Sales.Customer/Sales.Customer_Request/Sales.Request/Number
+ORDER BY Sales.Customer/Sales.Request_Customer/Sales.Request/Number
 ```
 
 | LastName     |

content/en/docs/refguide/modeling/domain-model/oql/oql-expression-syntax.md

@@ -25,6 +25,10 @@ Operators and functions in OQL use expressions as inputs to perform mathematical
 
 This document details the use and syntax of expressions in an OQL query.
 
+The domain model used in the various examples is shown below:
+
+{{< figure src="/attachments/refguide/modeling/domain-model/oql/oql-expression-syntax-domain-model.png" >}}
+
 ## Data Types
 
 OQL supports a set of data types that differ slightly from [Mendix data types](/refguide/data-types/). The supported data types are:
@@ -544,7 +548,7 @@ Where `expression` is an expression of any datatype.
 The `IS` operator can be used to filter out rows with values that are NULL. For example:
 
 ```sql
-	SELECT Revenue, Cost FROM Sales.Finance WHERE Revenue IS NOT NULL 
+	SELECT Revenue, Cost FROM Sales.Finances WHERE Revenue IS NOT NULL 
 ```
 
 | Revenue | Cost |
@@ -1141,18 +1145,18 @@ For example, a space delimited list can be converted to one with commas to be us
 SELECT * FROM Sales.Raw
 ```
 
-| ID | Import            |                                                         
+| ID | RawImport            |                                                         
 |----|-------------------|
 | -  | "6 D10 machinery" |
 | -  | "1 A15 tools"     |
 
 The text can be converted with `REPLACE` as follows:
 
 ```sql
-SELECT REPLACE(Import, ' ', ',') FROM Sales.Raw
+SELECT REPLACE(RawImport, ' ', ',') FROM Sales.Raw
 ```
 
-| Import            |                                                         
+| RawImport            |                                                         
 |-------------------|
 | "6,D10,machinery" |
 | "1,A15,tools"     |

content/en/docs/refguide/modeling/domain-model/oql/oql-expressions.md

@@ -20,6 +20,10 @@ An OQL expression is a query building block that returns a value or a list of va
 
 OQL expressions can be used in `WHERE`, `SELECT`, `GROUP BY`, `UNION`, `HAVING`, and `ON` conditions of `JOIN` clauses. For more information, see [OQL clauses](/refguide/oql-clauses/).
 
+The domain model used in the various examples is shown below:
+
+{{< figure src="/attachments/refguide/modeling/domain-model/oql/oql-expressions-domain-model.png" >}}
+
 ## Aggregations{#aggregates}
 
 Aggregations are functions that reduce a list of values from a retrieved column (or columns) into a single value. They can be used in the following ways:
@@ -173,7 +177,7 @@ SELECT MAX(Stock) as StockMax FROM Sales.Product
 To return the name(s) of the product(s) with the highest stock level you have to use a subquery. The subquery returns the maximum stock number, which is then compared to each product's stock in the `WHERE` clause:
 
 ```sql
-SELECT HighestStockProductName FROM Sales.Product
+SELECT Name AS HighestStockProductName FROM Sales.Product
 WHERE Stock = (SELECT MAX(P.Stock) FROM Sales.Product P)
 ```