# MultiSelect

The **MultiSelect** field is an input component that allows users to **select multiple values** from a dynamically retrieved list.\
Unlike **Checkbox**, which is typically UI‑focused, the MultiSelect field is designed to support **persistent multi‑value data storage**, often using a **separate relational (mapping) table**.

This field is especially useful for **many‑to‑many relationships** between entities.

***

### Purpose of MultiSelect Field

The MultiSelect field is designed to:

* Allow selection of **multiple values** from a dynamic data source
* Persist multiple selections in a separate destination table
* Support relational data modeling (parent–child / many‑to‑many)
* Reduce UI complexity compared to large checkbox groups

#### Typical Use Cases

* User assigned to multiple roles
* Product assigned to multiple categories
* Permissions or tags selection
* Skill sets, features, or attributes selection

***

### Adding and Configuring a MultiSelect Field

To add a MultiSelect field:

1. Drag the **MultiSelect** field into a Module layout
2. Click the **Edit (pencil) icon** on the field
3. The **MultiSelect Configuration** window opens

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***

### MultiSelect Configuration Properties

#### 1️. Core Identification

| Property  | Mandatory | Description                        |
| --------- | --------- | ---------------------------------- |
| **MF ID** | Yes       | System‑generated unique identifier |

***

#### 2️. Field Behavior

| Property          | Description                                                      |
| ----------------- | ---------------------------------------------------------------- |
| **Default Value** | Initial selected values (if any)                                 |
| **Source Tag**    | JavaScript injected at field level (e.g. `readonly`, `onchange`) |

***

#### 3️. Data Source Definition

These properties define where the selectable data is retrieved from.

| Property         | Mandatory | Description                             |
| ---------------- | --------- | --------------------------------------- |
| **Table Name**   | Yes       | Source table for selectable values      |
| **Column Show**  | Yes       | Column displayed to the user            |
| **Column Value** | Yes       | Column stored as selected value         |
| **Condition**    | No        | SQL condition to filter selectable data |
| **Alt Desc**     | No        | Alternate description field             |

***

#### 4️. Multi‑Value Persistence (Mapping Table)

These settings control how selected values are stored.

| Property                 | Description                                  |
| ------------------------ | -------------------------------------------- |
| **Destination Table**    | Table used to store multiple selected values |
| **Parent Key**           | Foreign key referencing the parent entity    |
| **MultiSelect List Key** | Column that stores selected values           |

> This design allows MultiSelect to model **many‑to‑many relationships** correctly.

***

#### 5️. Database Mapping (Main Entity)

| Property      | Description                                           |
| ------------- | ----------------------------------------------------- |
| **Field\_ID** | Database field mapped to this component (if required) |

***

#### 6️. Display & Search Configuration

| Property              | Description                                              |
| --------------------- | -------------------------------------------------------- |
| **ShowFieldName**     | Label displayed on the screen (auto‑generated supported) |
| **SearchCriteria**    | Enables field as search criteria                         |
| **ShowSearch**        | Displays field in search result table                    |
| **SearchFromTo**      | Enables range‑based search                               |
| **SearchPreLike**     | Enables wildcard `%XXX` search                           |
| **SearchLike**        | Enables wildcard `XXX%` search                           |
| **SearchIgnoreCase**  | Case‑insensitive search                                  |
| **JoinSearchTable**   | Used when JOIN SQL is required                           |
| **SearchFieldGroup**  | Horizontal position in search criteria                   |
| **SearchCriteriaSeq** | Vertical position in search criteria                     |
| **ShowSearchSeq**     | Order in search results                                  |

***

#### 7️. UI & Behavior Flags

| Property        | Description                               |
| --------------- | ----------------------------------------- |
| **Alignment**   | Text alignment: Left / Center / Right     |
| **OnlyGuiFlag** | UI‑only field (not persisted to database) |
| **ViewFlag**    | Displays field in read‑only mode          |
| **KeepHistory** | Persists history of value changes         |
| **FilterFlag**  | Filters records in 1‑Many Modules         |
| **Authen**      | Applies IAM‑based authorization           |
| **MergeFlag**   | Field spans across multiple columns       |

***

#### 8️. Validation Rules (Validate Code)

| Code                 | Description                             |
| -------------------- | --------------------------------------- |
| `CHECK_NULL`         | Prevents saving if no value is selected |
| `CHECK_INTEGER`      | Ensures integer value type              |
| `CHECK_DECIMAL`      | Ensures decimal value                   |
| `CHECK_EMAIL_FORMAT` | Validates email format                  |

***

### MultiSelect vs Checkbox

| Aspect               | MultiSelect   | Checkbox     |
| -------------------- | ------------- | ------------ |
| Data Source          | Dynamic (DB)  | Static       |
| Storage              | Mapping table | Single field |
| Best for Large Sets  | ✅ Yes         | ❌ No         |
| Many‑to‑Many Support | ✅ Native      | ❌ Limited    |
| UI Scalability       | ✅ High        | ⚠️ Limited   |

***

### Usage Guidelines

* Use **MultiSelect** for real relational multi‑value data
* Prefer MultiSelect over Checkbox for large datasets
* Always configure **Destination Table** and keys correctly
* Avoid using MultiSelect without persistence logic
* Test insert, update, and delete behavior thoroughly
* Index mapping tables for performance

***

### Summary

The **MultiSelect** field is a powerful component for managing **multiple related values** with proper relational persistence.

Key points:

* Supports true multi‑value selection
* Uses dedicated destination tables
* Ideal for many‑to‑many relationships
* Dynamic, scalable, and database‑driven
* Integrates with search, validation, and IAM

When used correctly, MultiSelect enables **robust data modeling and clean UI design** for complex enterprise Smart Forms in ONEWEB.


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