116 lines
5.4 KiB
Markdown
116 lines
5.4 KiB
Markdown
# DAL
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**Data Access Layer**
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DAL is a proxy layer for SQL databases with a MongoDB inspired query interface.
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It can be used as a Go or NodeJS package (requires compiler) to create your own proxy and apply custom middlewares.
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**Note:** This project is still in early alpha. You need to build it yourself and use at your own risk.
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**Note:** At the time only SQLite is implemented. However, other drivers might work.
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**Use cases**
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- For IOT networks when MySQL/PG are too heavy.
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- If you need a layer between your application and the database (i.e. for caching).
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- If you want a MongoDB-like query interface for your SQL.
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## Usage
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### Server
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The most efficient way to use DAL is to run the server as a standalone service.
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Build:
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```bash
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go build -o server
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```
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Run:
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```bash
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export SQLITE_DIRECTORY=/opt/data
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./server
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2024/08/21 22:01:54 Starting server on port 8118
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2024/08/21 22:01:54 Using directory: /opt/data
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```
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### Client
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Install:
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```bash
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pnpm add git+git@github.com:nesterow/dal.git
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```
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### Query Interface
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| Method | Description | SQL |
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| ---------------------------------------------- | -------------------------------------- | ---------------------------------------------------- |
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| In(table: string) | Select table | `SELECT * FROM table` |
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| Find(filter: object) | Filter rows | `SELECT * FROM table WHERE filter` |
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| Fields(fields: string[]) | Select fields | `SELECT fields, FROM table` |
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| Sort(sort: string) | Sort rows | `SELECT * FROM table ORDER BY sort` |
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| Limit(limit: number) | Limit rows | `SELECT * FROM table LIMIT limit` |
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| Offset(offset: number) | Offset rows | `SELECT * FROM table OFFSET offset` |
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| Join({ $for: "table_2", $do: { "t.a": "b" } }) | Join tables | `SELECT * FROM table t JOIN table_2 ON t.a = b` |
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| Insert({name: "Julian"}, {name: "Bob"}) | Insert row | `INSERT INTO table (name,) VALUES ('Julian', 'Bob')` |
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| Set({name: "Julian"}) | Update row (Find(filter).Set({})) | `UPDATE table SET name = 'Julian' WHERE filter` |
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| Delete() | Delete row (Find(filter).Delete()) | `DELETE FROM table WHERE filter` |
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| As(DTO) | Map rows to a DTO | `SELECT * FROM table` |
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| Rows() | Get rows iterator | `SELECT * FROM table` |
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| Exec() | Execute query (update, insert, delete) | `SQL RESULT` |
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| Query() | Query database | DTO array |
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| Tx() | Run in trasaction | |
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### Filters
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| Filter | Description | SQL |
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| --------------------------- | ---------------------- | ------------------------------ |
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| {id: 1, num: 2} | Equals, default filter | `WHERE id = 1 AND num = 2` |
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| {id: { $eq: 1 }} | Equals, explicit | `WHERE id = 1` |
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| {id: { $gt: 1 }} | Greater than | `WHERE id > 1` |
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| {id: { $gte: 1 }} | Greater than or equal | `WHERE id >= 1` |
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| {id: { $lt: 1 }} | Less than | `WHERE id < 1` |
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| {id: { $lte: 1 }} | Less than or equal | `WHERE id <= 1` |
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| {id: { $ne: 1 }} | Not equal | `WHERE id != 1` |
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| {id: { $in: [1, 2] }} | In | `WHERE id IN (1, 2)` |
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| {id: { $nin: [1, 2] }} | Not in | `WHERE id NOT IN (1, 2)` |
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| {id: { $like: "a" }} | Like | `WHERE id LIKE '%a%'` |
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| {id: { $nlike: "a" }} | Not like | `WHERE id NOT LIKE '%a%'` |
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| {id: { $between: [1, 2] }} | Between | `WHERE id BETWEEN 1 AND 2` |
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| {id: { $nbetween: [1, 2] }} | Not between | `WHERE id NOT BETWEEN 1 AND 2` |
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| {id: { $glob: "\*son" }} | Glob | `WHERE id GLOB '*son'` |
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### Example
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```typescript
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import { DAL } from "@nesterow/dal";
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class UserDTO {
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id: number = 0;
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name: string = "";
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data: string = "";
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age: number | undefined;
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}
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const db = new DAL({
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database: "test.sqlite",
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url: "http://localhost:8111",
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});
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const rows = db
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.In("test t")
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.Find({
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name: { $glob: "*son" },
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age: { $gte: 18 },
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}) // SELECT * FROM test t WHERE name GLOB '*son' AND age >= 18
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.As(UserDTO) // Map every row to DTO
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.Rows(); // Get iterator
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for await (const row of rows) {
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console.log(row); // Jason, Jackson
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}
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```
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