This article explains how and why Calculated Expression is used in MS Access. It also addresses an efficient way to properly use it.
An expression can be defined as a formula, which is used in Excel. Calculated Expression consists of multiple elements which can be used as a combination or individually to produce any desired result. Expressions can be a combination of logical or mathematical operators, controls, constants, functions, properties and table fields, which evaluates these functions into a single value.
Some of the Expression’s elements include:
- Identifiers — which are the names of table controls or fields on reports or forms, or their properties (fields or controls)
- Operators, like – (minus) or + (plus)
- Functions, like AVG or SUM
- Constants — Constant values which do not change — like numbers which are not calculated using an expression or strings of text.
Features and Functions of Calculated Expressions
- Users can use expressions to perform a variety of operations or tasks like supplying criteria to a particular query or to retrieve the value of any given control or for creating calculated fields and controls or for defining different levels for group reports.
- Like any expression, Calculated Expression is used for evaluating the properties of a particular control into a single value.
- As the name suggests calculated fields are used for displaying and calculating data, which is yet to be stored in the database.
- Users can use Calculated Expression on separate fields which are stored in a database.
- Calculated Expression operates by first accessing the database to retrieve the data, which is then formed into an equation, which is solved by MS Access interface.
Steps to Use Calculated Expression in MS Access
- Step 1: First and foremost, the user needs to open the MS Access file in which he/she wants to retrieve the information.
- Step 2: Then the user can run a query to get his/her desired results. For instance, you want to calculate the sales unit of a particular month or stock, you will have to multiply the number of books purchased with the book price.
- Step 3: Users need to create a full expression including, the OrderDetails, Quantity, RetailPrice and (XYZ) BooksNames, inside the square brackets, to allow MS Access to retrieve and read that specified data within the database.
Note here the exclamation mark is telling MS Access to review the table, for the field Quantity, and commanding it to multiply with the Retail price field, which is stored in the (XYZ) BooksName.
- Step 4: As soon as the user will run this query, the total price will be calculated and appear on the screen.
Users can use Calculated Expression for solving any form of the logistic or mathematical equation in their database. Users can also run multiple queries at a single time; however, we don’t recommend it as it can cause a lot of confusion. Calculated Expression can be used for solving queries like calculating the average, percentage, subtraction, probability etc. It is important to note that MS Access reads only a set amount of expressions, so it is necessary for the users to form an appropriate query for their equation to run properly.
While working on MS Access, you may at times encounter a database crash. To deal with such challenges, it is always advisable to keep a tool that can recover Access nearby.
Vivian Stevens is a data recovery expert in DataNumen, Inc., which is the world leader in data recovery technologies, including sql recovery and excel recovery software products. For more information visit www.datanumen.com