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url: >-
  /statelake/administering-statelake/designer/data-definitions/file-definitions/flat-file-definitions/design-flat-file-definitions/file-dataview-link-button-flat-file-definitions.md
---

# File Dataview - Link Button - Flat File Definitions

The second or alternate way of creating and maintaining a **Link** between the dataviews, is by the use of the **Link** button.

There is no **Link** tab within the definition itself, so any **Link** needs to be forged on the designer canvas. The **Link** button is only available and accessible off the design canvas, for a definition dataview that is able to be linked to another dataview.

With a definition holding more than one dataview, the **Link** button on every dataview is initially active.

Whichever dataview has the **Link** button that you click on, that dataview will become the linked dataview (detail) - not the **Master** (primary) dataview.

Clicking this button opens the **Link** window, as below. Where there are only two (2) dataviews, the name of the **Master** dataview to be linked into will automatically populate the settings window.

But you can also have multiple dataviews to chose from.

In this following example, the **BENEFITS** dataview has been selected as the link, leaving the **RECORD** and **IDENTIFIER** dataviews available for selection as the **Master** (primary) dataview that is to be linked to.

::: info
The colours of the link lines have no meaning.

They are random and arbitrary.

The colours of the link lines may be different every time that the definition is opened and the dataviews are viewed on the designer canvas.
:::

## Fields

| Field Name | Description |
|---|---|
| Detail - \<linked dataview> | A list of the fields in the dataview that is linked to the **Master** dataview. These fields belong to the dataview holding the **Link** button you clicked on. These fields are available to be selected to link to fields in the **Master** dataview. |
| Master | A drop-down list of the available dataviews that can be linked into. This list is only available where there are more than two (2) current dataviews available. |
| Master - \<primary dataview> | A list of the fields in the **Master** dataview that is linked. These fields are available to be selected to link to fields in the dataview. |
| Linked Fields | Shows the links that have been made between the fields in the dataviews. |

## Links Tab Buttons

| Button Name | Description |
|---|---|
| Add | **Add** a link. A field from both the **Detail** and **Master** lists will need to be selected before this button is activated. Once clicked, the fields will appear in **Linked Fields**. |
| Delete | Click to **Delete** a link. The button will activate only if a link is selected and highlighted in **Linked Fields**. |
| Clear | Click to **Clear** any and all field links. It severs all linkages made up to that point. |
| 1 | Include only those records from the **Master** dataview, for which matching records in the linked dataview can be found. |
| 2 | Include all records from the **Master** dataview, regardless of whether any matching records can be found in the linked dataview. |
| OK | Click **OK** to save any changes you have made. All changes will be lost if you do not click the **OK** button. |
| Cancel | Click to **Cancel** any changes you have made. |

::: info
While in theory you can link any field in one dataview to any field in any other dataview, it is usual to only link a **MASTER_ID**  to the **ID**  of the dataview being linked into.
:::

So to just illustrate the behaviour, the following example shows a link being forged between **NEIGHBOURS.NAME** and FRIENDS.NAME.

The link now shows under **Linked Fields**.

Note that the field **NAME** has been removed from the list of those available to link to the **Master** dataview.

Click **OK** and close this window and show this link on the designer canvas.

## SQL Tab

While you are able to change the **Linking SQL Generation** by selecting the appropriate radio button, the SQL code itself is displayed only, and cannot be altered in this window.

## SQL Tab Buttons

| Button Name | Description |
|---|---|
| Magic SQL | To activate **Magic SQL**, click this radio button. By default it is already selected. **Magic SQL** is powerful auto-generated hidden smart scripting feature that enables **Statelake** to keep track of the relationship between parent and child records across tables in a data definition.For more information, please review [Introduction to Magic SQL](/statelake/administering-statelake/designer/data-definitions/introduction-to-magic-sql). |
| Parameterised SQL | The **SQL** code fires each time the master record position changes, where the **SQL** is augmented with a parameter linked to the master record. |
| Manual SQL | The **SQL** code will be manually entered and stay as entered. |
| OK | Click **OK** to save any changes you have made. All changes will be lost if you do not click the **OK** button. |
| Cancel | Click to **Cancel** any changes you have made. |