---
title: "Engineering Functions"
slug: "baked-fields"
updated: 2023-11-06T18:31:21Z
published: 2023-11-06T18:31:21Z
canonical: "docs.datajet.app/baked-fields"
---

> ## 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.

# Baked Fields

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)

The engineering functions are organised into groups:

- **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

## Creating Baked Fields

BakedFields (or functions) can be created in a variety of ways:

- From the [Engineering | Functions menu](/v1/docs/function-overview)
- From the **Database Explorer | Right-click | Engineering | Functions** options
- From [Script](/v1/docs/scripting-methods-overview)
- By [editing an existing Baked Field](/v1/docs/database-right-click-menus)

Baked Fields are optimised functions that are designed to work quickly on very large datasets. Not all functions are supported for all data and field types. If a bakedfield function is not available for the particular field or data type that needs to be transformed, try one of the following:

- Expression Builder - (note, expressions may be slower than BakedFields)
- User-Defined Field
- Casting, or pre-engineering

See [Engineering - Functions](/v1/docs/function-overview) for more details.

## JSON and Parameters

Baked Fields have a common parameter structure:

#### Example Baked field (YMDH - Year Month Date Hour)

```json
{
  "method": "BuildBakedField",
  "project": "Election5",
  "targetTable": "PA_All",
  "overwrite": true,
  "name": "YMDH",
  "function": "datetimetransform",
  "p1": "YMDH(A)",
  "p2": "TimeStamp"
}
```

```json
{
  "method": "BuildBakedField",
  "targetTable": "transactions",
  "overwrite": true,
  "name": "Engineering-DMath",
  "function": "dmath",
  "p1": "A/B",
  "p2": "profit",
  "p3": "price",
  "nullIsZero": true,
  "project": "RegressionDB2"
}
```