# Creating Function Maps

A Function map object contains a function processing some incoming value (or values) according to the logic of the function selected. Astera provides a large number of built-in functions. They are broken by categories, for example, Math, Financial, Logical, SQL, Files, Date Time, General and others.

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For example, you can use the PMT (rate, periods, numperiods, PV) financial function to return payment for an annuity based on periodic, fixed payments and a fixed interest rate.

All functions return a result value of some appropriate data type. The function result is available via the output ports on the object box. For example the ParseName function, which parses a full name into separate pieces, could look like this:

![](https://3768133094-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FH4WCHHphSt0ALtMJlqot%2Fuploads%2FUOob6aoxzfEgKdozzMtd%2F0.jpeg?alt=media)

To add a *Function* map, drag the *Function* object from the *Maps* group in the Flow toolbox and drop it on the dataflow.

To configure the properties of a *Function* object after it was added to the dataflow, right-click on it and select *Properties* from the context menu. The following properties are available:

* *Function Map Properties screen:* provides the interface to help you select a function. You can select from the list of available functions arranged by Category, or you can display the entire list of available functions by selecting in the Category dropdown. Click on a function to select it.
* *General Options screen:* This screen shares the options common to most objects on the dataflow.

## **Examples**

### **Logical Functions**

#### **IsNotNull(Object)**

Returns Boolean TRUE if the specified object value does NOT contain a Null value. Otherwise returns FALSE.

Code

*Boolean IsNotNull(Object value)*

Parameters

Object value: An element of any data type specified by the expression.

Example

| **LoanID** | **LoanLTV** |
| ---------- | ----------- |
| 1          |             |
| 2          | 70          |
| 3          | 80          |

For the table above, the following expressions would return the corresponding results where LoanID = 1:

| **Code**           | **Returns the value** |
| ------------------ | --------------------- |
| IsNotNull(LoanLTV) | FALSE                 |

### **Date and Time Functions**

#### **Max(DateTime,DateTime)**

Returns the greater of the two given DateTime instances.

Code

*DateTime **Max**(DateTime first, DateTime second)*

Parameters

DateTime first: Represents an instant in time, typically expressed as a date and time of day.

DateTime second: Represents an instant in time, typically expressed as a date and time of day.

Example

| **Code**                                          | **Returns the value** |
| ------------------------------------------------- | --------------------- |
| Max(08/07/1996 11:29:13AM, 12/07/2006 04:29:13AM) | 12/07/2006 04:29:13AM |

## **Usage**

An example of a dataflow with NameParse and SplitString function is shown below:

![](https://3768133094-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FH4WCHHphSt0ALtMJlqot%2Fuploads%2F2Rt4dny0d2Grjj0yYjed%2F1.png?alt=media)