在Vapor 4中使用Fluent进行复杂查询

import Vapor
import Fluent

// 定义模型
final class User: Model {
    static let schema = "users"
    
    @ID(key: .id)
    var id: UUID?
    
    @Field(key: "name")
    var name: String
    
    init() {}
    
    init(id: UUID? = nil, name: String) {
        self.id = id
        self.name = name
    }
}

// 创建数据库迁移
struct CreateUser: Migration {
    func prepare(on database: Database) -> EventLoopFuture<Void> {
        return database.schema("users")
            .id()
            .field("name", .string)
            .create()
    }
    
    func revert(on database: Database) -> EventLoopFuture<Void> {
        return database.schema("users").delete()
    }
}

// 注册模型和迁移
func migrations(_ app: Application) throws {
    app.migrations.add(CreateUser())
    try app.autoMigrate().wait()
}

// 进行复杂查询
func complexQuery(_ req: Request) throws -> EventLoopFuture<[User]> {
    return User.query(on: req.db)
        .filter(\.$name == "John")
        .sort(\.$name, .ascending)
        .paginate(page: 1, per: 10)
        .all()
}