Table Procedural Macro

The Table procedural macro that simplifies the creation of SQL queries based on fields in your Rust structs. It comes with SELECT, INSERT, UPDATE, DELETE operations with JOINS, SUBQUERIES and other compled clauses. With this macro, you can generate these methods automatically, reducing boilerplate code and enhancing code readability.

Table of Contents

• Usage
• Examples

Usage

To use the Table procedural macro, follow these steps:

0. Add the prkorm crate to your Cargo.toml:

   [dependencies]
   prkorm = "0.1"
   

1. Import the Table procedural macro into your Rust code:

   use prkorm::Table;
   

2. Apply the #[derive(Table)] attribute to your struct. This will automatically generate select(), insert(), update() and delete() methods for all the struct including but not limited to table_primary_key(), table(), select_str(), select_field_name*() Then you can chain functions join function, where, having, limit, order by, group by etc based on the type of query you are opting for. Here is a quick example demonstrating the macro.

   #[derive(Table, Debug)]
   #[table_name("orders")]
   #[primary_key("id")]
   struct OrderModel {
       id: u32,
       customer_id: u32,
       address_id: u32,
       order_status: String,
       order_picture_url: String,
       created_at: String,
   }
   
   #[derive(Table, Debug)]
   #[table_name("customers")]
   struct Customer {
       id: u32,
       first_name: String,
       last_name: String,
   }
   

3. Use the generated methods as follows:

       let mut select_query: String = OrderModel::select()
       .select_str("CONCAT_WS(' ', `first_name`, `last_name`) as username ")
       .select_str("address_1")
       .left_join_by_customer_id(Customer::table(), "id")
       .left_join_by_address_id("addresses", "id")
       .order_by_created_at_desc()
       .where_order_status("PENDING")
       .having_order_status("PENDING")
       .build();
   
       println!("{}",select_query);
       //select_query:
       ```sql
       SELECT orders.id, orders.customer_id, 
       orders.address_id, orders.order_status, orders.order_picture_url, orders.created_at, 
       CONCAT_WS(' ', `first_name`, `last_name`) as username , address_1      
       FROM orders
       LEFT JOIN customers ON customers.id = orders.customer_id
       LEFT JOIN addresses ON addresses.id = orders.address_id
       WHERE orders.order_status = 'PENDING'
       HAVING orders.order_status = 'PENDING'
       ORDER BY orders.created_at DESC
       ```
   

Examples

Here are a few examples of how to use the Table procedural macro:

use prkorm::Table;

 #[derive(Table, Debug)]
    #[table_name("orders")]
    struct OrderModel {
        id: u32,
        customer_id: u32,
        address_id: u32,
        order_status: String,
        order_picture_url: String,
        created_at: String,
    }

    #[derive(Table, Debug)]
    #[table_name("customers")]
    struct Customer {
        id: u32,
        mobile_number: u64,
        first_name: String,
        last_name: String,
    }

fn main() {
    // SELECT QUERY
    let mut select_query = OrderModel::select()
                            .where_customer_id_in(
                                Customer::select_id()
                                    .where_mobile_number_condition("!=","NULL")
                                    .build()
                                )
                            .build();

    // Output
    println!("{}", select_query);
    ```sql
    SELECT orders.id, orders.customer_id, orders.address_id, orders.order_status, orders.order_picture_url, orders.created_at
    FROM orders
    WHERE orders.customer_id IN (SELECT customers.id
    FROM customers
    WHERE customers.mobile_number != 'NULL')
    
    ```
    

    // INSERT QUERY
    let insert_query = Customer::insert()
                        .insert_to_first_name("Prakash")
                        // OR "9876543210"
                        .insert_to_mobile_number(9876543210u64) 
                        .build();

    // Output
    println!("{}", insert_query);

    ```sql
    INSERT INTO customers
    (first_name, mobile_number) VALUES  ('Prakash', '9876543210')
    ```

    
    // UPDATE QUERY: Note => No build() in update()
    let update_query =  Customer::update()
                        .update_first_name_with_value("JOHN")
                        .update_last_name_with_value("WICK")
                        .update_where_mobile_number_eq("9876543210");


    // Output
    println!("{}", update_query);

    ```sql
    UPDATE customers SET last_name = 'WICK', first_name = 'JOHN' 
    WHERE mobile_number = '9876543210'


    // DELETE QUERY: Note =>No build() in delete()
    let delete_query =  Customer::delete()
                        .delete_where_mobile_number_eq("9876543210");


    // Output
    println!("{}", update_query);

    ```sql
    DELETE FROM customers WHERE mobile_number = '9876543210'
    ```



}

```rust
#[derive(Table)]
#[table_name("posts")]
#[table_alias("P")]
#[primary_key("id")]
struct Post {
    id: i32,
    title: String,
    user_id: i32,
}

#[derive(Table)]
#[table_name("users")]
#[table_alias("U")]
struct User {
    id: i32,
    username: String,
}

fn main() {
    let query = User::select_str_as(
        &Post::select_function_over_field_name("COUNT", "*")
            .where_user_id(User::id())
            .build(),
        "total_post_count",
    )
    .where_id(1)
    .build();

    println!("{query}");
}

    ```sql
    SELECT 
    (SELECT COUNT(*) FROM posts P WHERE P.user_id = U.id) AS total_post_count  
    FROM users U
    WHERE U.id = '1'
    ```