---
title: "CTOD"
slug: "ctod"
updated: 2023-03-24T13:16:56Z
published: 2023-03-24T13:16:56Z
canonical: "docs.datajet.app/ctod"
---

> ## 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.

# CTOD

## String: CTOD

## Attempts to create a new discrete field, usually by having applied a filter to a continuous string, integer or double.

## Purpose

Use this function to:

- Create a discrete field from a continuous field
- Create a copy of a continuous field for use as a dimension in a profile
- Create a copy of a field for use in a join
- Turn a C (continuous) into a D (discrete)

Processing TimeCTOD can take a long time to run (i.e., upwards of 1 minute) if the following conditions are met:

- Large number of records on the table (> 50 million)
- Large number of discrete values (>300,000)

CTOD will fail if the number of discrete values in field A exceeds the threshold which is 300,000 by default.     The threshold can be increased by running a BuildBakedField method in script editor and setting MAX_ENTRIES up to 2 million.   However, this can increase processing time significantly, so should only be done where necessary.  

## Return Value

| Property | Value |
| --- | --- |
| **FieldType** | String / Integer / Long(Integer) / Double |
| **FieldSize** | Low / Med / High |
| **DataType** | Discrete |
| **DataSize** | Short / Integer / LongInteger / Double |

```shell
Example Return Value: Return values are unchanged from Input value.   CTOD is not applicable for Dates or DateTimes.
```

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

## Parameters

| Parameter | JSON | Description |
| --- | --- | --- |
| **Table** | “targetTable”: “MyTableName” | The target table on which the new field will be created |
| **Filter** | “dataset”: {DataSet_JSON} | Optional. If a filter is applied, records not in the filter recordset will be returned as null. |
| **Function** | "function":"" | String |
| String Function | “p1”: “CTOD(A)” | CTOD(A) |
| A | “p2”: | Required. The discrete field to copy as a continuous field. *Supports:* - **DataType:** Discrete - **Field Type:** Integer, Double, String |
| MAX_ENTRIES |  | The threshold for crossing from discrete data type to continuous data type. |

## JSON Sample

```json
{
  "method": "BuildBakedField",
  "targetTable": "BikeTripData",
  "overwrite": true,
  "name": "Journey_Random2",
  "function": "string",
  "p1": "CTOD(A)",
  "p2": "Journey_ID",
  "MAX_ENTRIES": 1000000,
  "project": "Model1"
}
```

## Usage Notes

On very large tables, it may be necessary to use a filter in order to extract a discrete field from a continuous field. In the example below, a random sampe of size 800,000 has been applied to the BikeTripData table in order to create the Journey_Random field.

![CTOD_Example1](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/CTOD_Example1.PNG)

Another approach is to use the BuildBakedField method and extend the MAX_ENTRIES threshold. This approach should be used with care, as DataJet's threshold limits are designed to maximize performance across the application. Having a large number of very high cardinality indexed fields (i.e., string fields above 200,000 unique values) may result in a perceptible (i.e., greater than 1 second) response time for operations such as populating the Context Panel grid.

<font color="#fac51c">&lt;&lt;TODO: &nbsp; Analyse field function &gt;&gt;</font>

![CTOD_Example2](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/CTOD_Example2.PNG)

See Also:

- [QQ - How do I use the integrated model processor on very large tables?](https://datajet.document360.io/docs/qq-how-do-i-use-the-integrated-model-processor-on-very-large-tables)
- [Getting Started - Data Types](https://datajet.document360.io/docs/getting-started-data-types)
- [Expression Field](/v1/docs/expression-field)

## Example

| Example | Details |
| --- | --- |
| **Description** | Convert a continuous string field to a discrete string |
| **Input** | - Table: = [BikeTripData] - Filter: = [No Filter] - **Function: = String** - String Function: = CTOD(A) - A:= [BikeTripData].[JourneyID] - Name: = Journey_Random2 |
| **Sample** | ![CTOD_Example3](https://cdn.document360.io/73b6469b-c1e4-47e9-aa65-986c8ebd17ca/Images/Documentation/CTOD_Example3.PNG) |