sqlite - Sqlite.swift没有这样的表错误

Question

我创建了一个函数，用于使用sqlite.swift将json数据映射到sqlite存储。尽管自从我第一次尝试运行插入操作时，我收到一个奇怪的行为，但是却收到“没有这样的表”错误。 .instance.connect（）。然后，每次放置插入调用时，它将初始化该表，以确保该表已使用数据中的所有列进行设置。

//附加到按钮

let userJSON = JSON(["user_id" : id, "username" : email])

SQLData.instance.insert(table: "users", data: userJSON) { result in
        if let result = result{
                print(result)
        }
}

// sql类

class SQLData {
    static let instance = SQLData()
    var db: Connection? = nil

    func connect() {
        let path = NSSearchPathForDirectoriesInDomains(
            .documentDirectory, .userDomainMask, true
            ).first!
        do {
            self.db = try Connection("\(path)/contacts.sqlite3")
            if let db = self.db {
                try db.run(Table("users").drop(ifExists: true))
            }
            print("SQLite connection established.")
        } catch {
            print("Couldn't create SQLite connection.")
        }
    }

    func initTable(table: String, data: JSON, completionHandler: (Table?) -> Void){
        if let db = db {
            let t = Table(table)

            do {
                try db.run(t.create(temporary: false, ifNotExists: true) { r in
                    r.column(Expression<Int>("id"), primaryKey: true)
                    r.column(Expression<Bool>("synced"), defaultValue: false)

                    for (key,val) in data {
                        if val.bool != nil{
                            r.column(Expression<Bool>(key), defaultValue: false)
                        } else if val.int != nil {
                            r.column(Expression<Int>(key), defaultValue: 0)
                        } else if val.double != nil {
                            r.column(Expression<Double>(key), defaultValue: 0.0)
                        } else {
                            r.column(Expression<String?>(key), defaultValue: "")
                        }
                    }
                    completionHandler(t)
                })
            } catch let err {
                print(err)
                completionHandler(nil)
            }
        } else {
            completionHandler(nil)
        }
    }

    func insert(table: String, data: JSON, completionHandler: @escaping (Int64?) -> Void){
        self.initTable(table: table, data: data) { t in
            if let db = db, let t = t {
                var query: [Setter] = []
                for (key, val) in data {
                    if val.bool != nil{
                        query.append(Expression<Bool>(key) <- val.boolValue)
                    } else if val.int != nil {
                        query.append(Expression<Int>(key) <- val.intValue)
                    } else if val.double != nil {
                        query.append(Expression<Double>(key) <- val.doubleValue)
                    } else {
                        query.append(Expression<String?>(key) <- val.stringValue)
                    }
                }
                do {
                    try db.transaction {
                        let insert = t.insert(query)
                        let rowid = try db.run(insert)
                        completionHandler(rowid)
                    }
                } catch let err {
                    print(err)
                    completionHandler(nil)
                }
            } else {
                completionHandler(nil)
            }
        }
    }
}

Answer 1

如下更改连接功能

func connect(){
    do {
        let databaseFilePath = Bundle.main.path(forResource: "contacts", ofType: "sqlite3")!
        db = try Connection(databaseFilePath)
    } catch {
        print(error)
    }
}

并确保将.sqlite3（或.db）文件放入项目层次结构中，并复制捆绑包资源（例如图像）