Entity Definition

Field Manual Section 5 - Unit Schematics

Lock and load, soldier! In Tank's war machine, the "Entity" is your frontline fighter. A Rust struct rigged with the #[derive(Entity)] macro that maps straight to a database table and gives you convenient functions to access and modify the data. Tank automatically handles the heavy lifting of converting Rust values to database columns and back.

Before you can deploy entities, you must have an operational connection (see Field Manual Section 3 - Supply Lines). All entity operations execute through either a live connection or a locked transaction; without a supply line, your units can't move.

Mission Briefing

Zero boilerplate. Define a struct, tag it, deploy. Tank matches your Rust field types to the closest database type for each driver. Unified arsenal, same blueprint across all battlefields.

Entity

Start with a plain Rust struct and derive the tank::Entity trait. The fields can have any of the types supported (see Field Manual Section 4 - Payload Specs)

#[derive(Entity)]
#[tank(schema = "ops", name = "missions", primary_key = (Self::code_name, Self::start_time))]
pub struct Mission {
    pub code_name: String,
    pub start_time: Passive<PrimitiveDateTime>,
    #[tank(references = armory.weapons(serial_number))]
    pub primary_weapon: Option<i64>,
    pub objectives: Vec<String>,
    pub success_rate: f32,
    pub casualties: Option<u16>,
}

Notes:

• tank::Passive<T> lets the database provide or retain a value: omit it when updating, or allow default generation on insert.
• Option<T> marks the column nullable.

You have now forged a battle-ready map of your database. Create, destroy, deploy new records or extract targets one-by-one. Execute every maneuver through a live connection or a locked transaction for maximum firepower.

Attributes

Tank's #[tank(...)] attributes are your weapon mods, fine-tuning structs for precision strikes.

• structfield name = "the_name": Table name on a struct / column name on a field. Default: snake_case of identifier.
• struct schema = "your_schema": Database schema. Default: none.
• struct primary_key = "some_field" or primary_key = ("column_1", Self::column_2, ..): Table primary key.
• field primary_key: Marks field as part of primary key. Cannot be combined with struct-level primary_key.
• struct unique = "some_field" or unique = ("column_1", Self::column_2, ..): Unique constraint.
• field unique: Field-level unique constraint.
• field default: Default value expression for the column.
• field references = OtherEntity::column: Foreign key reference.
• field ignore: Excludes field from table and from row materialization.
• field type = "RAW_DB_TYPE": Override column type in DDL (driver-portability risk).

All units accounted for. Stand by.