> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nativeline.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Supabase Database
> Store and query data in PostgreSQL
# Supabase Database
Supabase provides a full PostgreSQL database for storing your app's data. Create tables, write queries, and let your data scale.
## Prerequisites
* [Supabase connected](/integrations/supabase/setup)
* Basic understanding of your data needs
***
## Creating Tables
### In Supabase Dashboard
1. Go to **Table Editor** in sidebar
2. Click **Create a new table**
3. Name your table (e.g., `tasks`)
4. Add columns
### Via Nativeline
You can also ask Nativeline:
```
Create a Supabase table for tasks with:
- id (auto-generated UUID)
- user_id (links to auth users)
- title (text, required)
- is_completed (boolean, default false)
- created_at (timestamp, auto)
```
***
## Common Column Types
| Type | Use For | Example |
| ------------- | ------------ | ------------------------- |
| `uuid` | Unique IDs | Primary key, foreign keys |
| `text` | Strings | Names, descriptions |
| `int4/int8` | Numbers | Counts, quantities |
| `bool` | True/false | Is completed, is active |
| `timestamptz` | Dates/times | Created at, due date |
| `jsonb` | Complex data | Settings, metadata |
| `float8` | Decimals | Prices, coordinates |
***
## Example: Tasks Table
```sql theme={null}
CREATE TABLE tasks (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
user_id UUID REFERENCES auth.users(id) NOT NULL,
title TEXT NOT NULL,
description TEXT,
is_completed BOOLEAN DEFAULT false,
due_date TIMESTAMPTZ,
created_at TIMESTAMPTZ DEFAULT now(),
updated_at TIMESTAMPTZ DEFAULT now()
);
```
***
## Row Level Security (RLS)
Always enable RLS on tables with user data. Without it, anyone with your API key can read everything!
### Enable RLS
1. Table Editor → Select table
2. Toggle "RLS" to enabled
3. Add policies
### Common Policies
**Users see only their data:**
```sql theme={null}
CREATE POLICY "Users view own tasks"
ON tasks FOR SELECT
USING (auth.uid() = user_id);
```
**Users create own data:**
```sql theme={null}
CREATE POLICY "Users create own tasks"
ON tasks FOR INSERT
WITH CHECK (auth.uid() = user_id);
```
**Users update own data:**
```sql theme={null}
CREATE POLICY "Users update own tasks"
ON tasks FOR UPDATE
USING (auth.uid() = user_id);
```
**Users delete own data:**
```sql theme={null}
CREATE POLICY "Users delete own tasks"
ON tasks FOR DELETE
USING (auth.uid() = user_id);
```
***
## CRUD Operations
### Create (Insert)
```
Add a function to create a new task with the given title.
Save it to Supabase with the current user's ID.
```
### Read (Select)
```
Load all tasks for the current user from Supabase.
Order them by created_at, newest first.
```
### Update
```
Add a function to mark a task as complete.
Update the is_completed field in Supabase.
```
### Delete
```
Add a function to delete a task from Supabase.
Show confirmation before deleting.
```
***
## Querying Data
### Basic Queries
```swift theme={null}
// All tasks for current user (handled by RLS)
let tasks = try await supabase
.from("tasks")
.select()
.execute()
// Filter by completion status
let incomplete = try await supabase
.from("tasks")
.select()
.eq("is_completed", value: false)
.execute()
// Order by date
let ordered = try await supabase
.from("tasks")
.select()
.order("due_date", ascending: true)
.execute()
```
### Filtering Options
| Method | Use | Example |
| --------- | ---------------- | ------------------------------------- |
| `.eq()` | Equals | `eq("status", "active")` |
| `.neq()` | Not equals | `neq("status", "deleted")` |
| `.gt()` | Greater than | `gt("price", 100)` |
| `.lt()` | Less than | `lt("age", 30)` |
| `.gte()` | Greater or equal | `gte("rating", 4)` |
| `.like()` | Pattern match | `like("name", "%John%")` |
| `.in()` | In array | `in("status", ["active", "pending"])` |
| `.is()` | Is null/bool | `is("deleted_at", nil)` |
***
## Relationships
### One-to-Many
Tasks belong to a category:
```sql theme={null}
CREATE TABLE categories (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
user_id UUID REFERENCES auth.users(id),
name TEXT NOT NULL
);
CREATE TABLE tasks (
...
category_id UUID REFERENCES categories(id),
...
);
```
### Querying with Relationships
```swift theme={null}
// Get tasks with category names
let tasks = try await supabase
.from("tasks")
.select("*, categories(name)")
.execute()
```
***
## Handling Errors
### Common Database Errors
| Error | Cause | Solution |
| --------------------- | ---------------------- | ----------------------------- |
| RLS policy violation | No matching policy | Check your policies |
| Foreign key violation | Referenced row missing | Ensure referenced data exists |
| Not null violation | Required field empty | Provide all required fields |
| Unique violation | Duplicate value | Check for existing records |
### Error Handling in App
```
Handle database errors gracefully:
- Show user-friendly error messages
- Log detailed errors for debugging
- Retry on network errors
```
***
## Performance Tips
If you often query by a column (like `user_id`), add an index:
```sql theme={null}
CREATE INDEX tasks_user_id_idx ON tasks(user_id);
```
Instead of `select("*")`, specify columns:
```swift theme={null}
.select("id, title, is_completed")
```
```swift theme={null}
.range(from: 0, to: 19) // First 20 items
```
Store frequently-accessed data locally and sync with Supabase.
***
## Testing Database Operations
### In Supabase Dashboard
1. Table Editor → Select table
2. View, add, edit, delete rows manually
3. Great for testing and debugging
### Via SQL Editor
1. SQL Editor in Supabase sidebar
2. Write and run queries directly
3. Test policies and queries
***
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