> For the complete documentation index, see [llms.txt](https://docs.informationhub.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.informationhub.io/project/tables/create-table.md).
# Create a Table
To start storing data in your project, you first need to create a table and define its columns.
## Create the table
1. Open your project and click **Tables** in the sidebar.
2. Click the **+** button to open the create table dialog.
3. Enter a name for your table.
4. The primary key is set up automatically as an auto-incrementing integer column called `id`. You can rename it if needed. To use a human-readable ID instead (for example `OBS-1`), assign a key generator to the primary key column after creating the table - see **Key generators** below.
5. Click **Create**.
Creating a new table
Your table is created with just the primary key column. Next, add the columns you need.
## Add columns
1. In the table view, click the **+** button on the table header (or click **ADD** in the toolbar and select **Add Column**).
2. Enter a name for the column.
3. Select a data type from the dropdown.
4. Optionally toggle **Required** to prevent the field from being left empty.
5. Optionally toggle **Unique** to prevent duplicate values in this column.
6. Optionally select a **Key Generator** to auto-populate the primary key with generated values (see below).
7. To add more columns at the same time, click **Add another column** and fill in the next row.
8. Click **Save** when you are done.
Adding a column
{% hint style="info" %}
You can add multiple columns in one go. Use the **Add another column** button to add extra rows before saving, so you only need to submit the form once.
{% endhint %}
## Column types
Choose the right data type for each column. Using the correct type prevents data entry errors and makes analysis easier.
### Text
Stores free text of any length. Use it for names, descriptions, codes, notes, or any value that does not fit a more specific type. Stored as `TEXT` in the database. Text can also be used as a primary key.
### Integer
Stores whole numbers with no decimal part. Use it for counts, IDs, or any value that is always a round number. Stored as `INT`. Integer columns can be set to **auto-increment** when used as the primary key.
### Real
Stores decimal numbers at standard precision (roughly 6 significant decimal places). Use it for measurements where exact precision beyond 6 digits is not needed - for example, pH readings, percentages, or short coordinates.
### Double Precision
Stores decimal numbers at high precision (up to 15 significant decimal places). Use it when accuracy matters - for example, GPS coordinates, financial figures, or scientific measurements. Use Double Precision over Real when in doubt.
### Yes / No
Stores a boolean true/false value. Displayed as a toggle in the data entry form. Use it for binary questions: "Collected?", "Verified?", "Active?".
### File
Stores a reference to one or more files. Each uploaded file is stored in your project's **Storage** and the cell holds the file names and their storage URLs. In the table grid, File cells render as clickable links that open the file in a new tab.
{% hint style="info" %}
**File columns are text under the hood.** The cell value is a text string in `filename[url],` format. This means you can also manually type an external URL (such as a DOI link or external resource) using the same format - for example: `Paper[https://doi.org/10.xxxx/example]`. The cell will render it as a clickable link without any upload required.
{% endhint %}
### Dropdown
Stores a selection from a predefined list of options. The options are defined when linking the column to a form question. Stored as text internally. Use it for fields with a fixed set of valid values - for example, site names, status codes, or category labels.
### Foreign Key
Stores a reference to a row in another table in the same project. The stored value is the primary key of the referenced row. Use it to link records across tables and avoid data duplication - for example, linking an observation row to a row in a Sites table instead of repeating the site name on every row.
When adding or editing a row, Foreign Key columns present a search interface to find and select the referenced record.
### JSON
Stores structured data as a JSON value in a single cell. Use it when you need to record a collection of related attributes that do not fit a flat column structure. The form builder's **JSON** question type links to this column type.
### Tabular
Stores multiple rows of structured data within a single cell. Use it for forms where respondents need to enter a variable number of sub-records in one submission - for example, multiple measurements taken at one site visit. Linked to the **Tabular** question type.
***
## Edit a column
To change a column's name, type, or settings after it has been created:
1. In the table view, click the **pencil icon** on the column header you want to edit.
2. Update the column name, type, Required/Unique toggles, or key generator assignment.
3. Click **Save**.
{% hint style="warning" %}
If you change a column's data type, a warning will appear if the change could affect existing data. Review the warning carefully before confirming.
{% endhint %}
You can also delete a column permanently from the edit column form using the **Delete Column** button. This cannot be undone.
***
## Key generators
A key generator auto-populates the primary key column with values based on a template pattern. This is useful for human-readable sample IDs, serial numbers, or any code that follows a consistent format.
{% hint style="info" %}
If your key generator template includes literal text (for example `OBS-{autoincrement}` or `SP-{uuid[0:8]}`), the primary key column type must be **Text**, not **Integer**. Open **Edit Column** on the primary key column and change its type to Text before assigning the generator.
{% endhint %}
Key generators are **project-level** - one generator can be reused across multiple tables. They are assigned to the primary key column of a table at creation time or by editing the primary key column.
### Managing key generators
Key generators are managed from the **Tables list** page:
1. Click **Tables** in the project sidebar.
2. Click the **Key Generators** button in the toolbar.
3. Click **+** to create a new generator.
4. Enter a **Name**, an optional **Description**, and a **Template** string (see tokens below).
5. Click **Create**.
To edit or delete an existing key generator, use the edit (pencil) or delete icons next to each entry in the list.
Once a key generator exists, assign it to a table's primary key column when creating the table, or by opening **Edit Column** on the primary key column.
### Template tokens
Templates are strings that mix literal text with tokens in `{...}` syntax. Tokens are replaced with generated values when a new row is inserted.
| Token | What it produces | Example output |
| ----------------- | ----------------------------------------------- | -------------------------------------- |
| `{autoincrement}` | An atomically incrementing integer (1, 2, 3...) | `42` |
| `{uuid}` | A random v4 UUID | `f47ac10b-58cc-4372-a567-0e02b2c3d479` |
| `{cuid}` | A collision-resistant unique ID | `clh3z8k0v0000qzrmabcd1234` |
| `{date}` | Current date as `YYYY-MM-DD` | `2026-05-26` |
| `{date:FORMAT}` | Current date in a custom moment.js format | `{date:YYYYMMDD}` → `20260526` |
| `{time}` | Current time as `HH:mm:ss` | `14:32:07` |
| `{time:FORMAT}` | Current time in a custom moment.js format | `{time:HHmm}` → `1432` |
| `{datetime}` | Current date and time (ISO 8601) | `2026-05-26T14:32:07+00:00` |
| `{columnId}` | Value of another column in the same row | `Site Alpha` |
### Slicing token output
Any token can be sliced to take only part of the generated value, using Python-style `[start:end]` notation immediately after the token name:
* `{uuid[0:8]}` - first 8 characters of a UUID
* `{cuid[0:12]}` - first 12 characters of a CUID
* `{autoincrement[0:4]}` - first 4 digits of the counter
### Formatters
Add `:lower`, `:upper`, or (for column references) `:slug` after the token to transform the output:
* `{uuid:upper}` - UUID in uppercase
* `{date:YYYYMMDD}` - date formatted as `20260526` (the `:FORMAT` string is the formatter for date/time tokens)
* `{siteColumnId:slug}` - column value lowercased with spaces replaced by hyphens
### Working examples
**Sequential observation IDs**
```
OBS-{autoincrement}
```
Produces: `OBS-1`, `OBS-2`, `OBS-3`, ...
**Date-prefixed short UUID**
```
{date:YYYYMMDD}-{uuid[0:8]:upper}
```
Produces: `20260526-F47AC10B`, `20260526-A3B2C1D0`, ...
**Site-prefixed sequential ID** (where `clm8abc123def456xyz` is the column ID of the `site` column)
```
{clm8abc123def456xyz:slug}-{autoincrement}
```
Produces: `site-alpha-1`, `site-beta-2`, ...
**Short CUID for compact IDs**
```
SP-{cuid[0:8]}
```
Produces: `SP-clh3z8k0`, `SP-clh3z8k1`, ...
{% hint style="info" %}
To find a column's ID for use in a template, look at the column's URL when editing it, or ask a developer with database access. Column IDs are 20-40 alphanumeric characters.
{% endhint %}
{% hint style="warning" %}
Key generators can only be assigned to **primary key columns**. They apply to new rows only - existing rows keep their original primary keys.
{% endhint %}
***
## Table settings
The **Settings** button in the table toolbar opens the table settings page, where you can:
* **Rename the table** - update the table name and click Save.
* **Clear all data** - deletes every row in the table but keeps all the columns and structure intact.
* **Delete the table** - permanently removes the table and all its data.
{% hint style="warning" %}
**Clear all data** and **Delete table** are permanent actions and cannot be undone. Export your data first if you need a backup.
{% endhint %}
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