---
title: "Function Overview"
slug: "function-overview"
updated: 2023-11-06T18:31:12Z
published: 2023-11-06T18:31:12Z
canonical: "docs.datajet.app/function-overview"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.datajet.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Function Overview

Function fields - also known as "BakedFields" - are inbuilt DataJet functions that can be applied to existing data fields in order rapidly create new fields. Along with [Expressions](/v1/docs/expression-field), [DataSetFields](/v1/docs/dataset-hotbar-quick-reference) and [User-Defined Fields](/v1/docs/programmed-field) they play a key role in the **transformation** of data.

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1699288891865.png)

See [Baked Fields](/v1/docs/baked-fields) for an overview of Baked Fields

## Find Function

Accessed via **Engineering | Functions | Find Function**

The Find Function dialog allows functions to be searched for via keywords:

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1699290320078.png)

It is also possible to filter results by function group.

Double-click a function to bring up the function selector.

## Function Selector

Accessed via **Engineering | Functions | Selector**

The Function Selector Dialog first requires either a function group, or a general function to be selected.

(Click the search icon to bring up the function search dialog)

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1699290848933.png)

Select a function/group and sub function

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1699291215548.png)

- Enter table that that field is to be created on
- Apply a filter of records to be included when building the new field (optional - if not provide, all records in the source table will be included)
- Enter parameters
- Specify a name for the new field
- Click Build

### Parameters

Parameters can be of two types:

- fields
- fixed values

fixed values must be prefixed by the pound sign (#):

![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1699295236104.png)

Methods for Adding ParametersParameters can be added to the function dialog in the following ways:

- Drag and drop from the [Database Explorer](/v1/docs/project-explorer-overview)
- Type the parameter name or value
- Select the required field in the Database Explorer, press  CTRL C to copy the field name to clipboard, and then do CTRL V to paste into the fnuction dialog
- Select the required field from the drop down

#### Do Not Ordinalize

If available and checked, this will force the field to be created as a continuous field. Note this added the "flags": "NOORD" key to the executed JSON:

```json
{
  "method": "BuildBakedField",
  "project": "Election5",
  "targetTable": "PA_All",
  "overwrite": true,
  "name": "NoOrd",
  "function": "string",
  "p1": "CONCAT(A,B,C,D,E,F)",
  "p2": "geo_id",
  "p3": "#_",
  "p4": "locality_fips",
  "flags": "NOORD"
}
```

#### Properties

To see the JSON that was used to create a BakedField, select the field in the Database Explorer, right-click and choose Properties: ![](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/image-1699295364160.png)

#### Existing Fields

Using an existing field as a templateTo create a copy of an existing field, select it in the Project Explorer, right-click and choose Edit - the function dialog will be opened with the parameters for the existing field. Change the function name to be the name of the new field, click build, and a copy of the field will be created.Existing FieldsIf a field of the specified name already exists, an overwrite prompt will be displayed.   Choosing to overwrite will permanently change the existing field content.    If a field is written over by mistake, access the [Project History](/v1/docs/import-definitions) to retrieve the earlier version.

## Functions

The following function groups are available on the function menu:

- **General** - general functions, including key creation, discrete value processing, access to indexes, joinlayer functions and quantiles.
- [**DateTimeTransform**](/v1/docs/datetime-transform-overview) - transformations involving hours, minutes and seconds
- [DateTransform](/v1/docs/dmath-overview) - transformations involving years, months and days
- [DMath](/v1/docs/dmathfunction-1) - transformations producing decimal fields
- [**LMath**](/v1/docs/lmath-overview) **-** transformations that produce integer fields
- [FLogic](/v1/docs/flogic-overview) - logical functions that evaluate conditions and produce flag fields
- **Geo** - geographical functions, including distance calculations
- **Statistical** - distributions and transformation that support data modelling and cleaning
- **String** - transformations of string data
- **UserAgent** - extractions of web data

The function menu can be accessed via:

- **Engineering | Functions** - Hover over a function to display the tooltip description of the function's purpose:
- [**Database Tree | Field Right-Click | Engineering**](/v1/docs/database-right-click-menus)