Xcode中SQLite的绑定错误

Question

我对Xcode相当陌生，尤其是Xcode中的sqlite，我收到一个错误，我不知道如何解决。我已经在Xcode之外使用SQLite和类似Python的语言，但是它的工作方式与此不同。

import UIKit
import SQLite3

class ViewController: UIViewController, UITextFieldDelegate {

var db: OpaquePointer?

override func viewDidLoad() {
    super.viewDidLoad()

    let fileUrl = try!
        FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false).appendingPathComponent("testDB.sqlite3")

    if sqlite3_open(fileUrl.path, &db) != SQLITE_OK{
        print("Error opening database.")
        return
    }

    let createTableQuery = "CREATE TABLE IF  NOT EXISTS test (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, strength TEXT)"

    if sqlite3_exec(db, createTableQuery, nil, nil, nil) != SQLITE_OK{
        print("Error creating table.")
        return
    }

    print("Database created.")
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    self.view.endEditing(true)

}

//Properties
@IBOutlet weak var inputName: UITextField!
@IBOutlet weak var inputStrength: UITextField!

//Action
@IBAction func buttonConfirm(_ sender: Any) {
    let name = inputName.text?.trimmingCharacters(in: .whitespacesAndNewlines)
    let strength = inputStrength.text?.trimmingCharacters(in: .whitespacesAndNewlines)

    if(name?.isEmpty)!{
        print("Name is empty.")
        return;
    }

    if(strength?.isEmpty)!{
        print("Strength is empty.")
        return;
    }

    var stmt: OpaquePointer?

    let insertQuery = "INSERT INTO testDB (name, strength) VALUES(?, ?);"

    if sqlite3_prepare(db, insertQuery, -1, &stmt, nil) != SQLITE_OK{
        print("Error binding query.")
    }

    if sqlite3_bind_text(stmt, 1, name, -1, nil) != SQLITE_OK{
        print("Error binding name.")
    }

    if sqlite3_bind_text(stmt, 2, strength, -1, nil) != SQLITE_OK{
        print("Error binding strength.")
    }

    if sqlite3_step(stmt) == SQLITE_DONE{
        print("Values saved successfully.")
    }

    }

}

我的大多数错误是“没有用空准备语句调用API”，没有任何查询绑定。

Database created.
Error binding query.
2019-11-20 09:32:18.381316+0000 PharmAssist[27925:1197718] [logging] API called with NULL prepared statement
2019-11-20 09:32:18.381453+0000 PharmAssist[27925:1197718] [logging] misuse at line 89232 of [378230ae7f]
Error binding name.
2019-11-20 09:32:18.381601+0000 PharmAssist[27925:1197718] [logging] API called with NULL prepared statement
2019-11-20 09:32:18.381719+0000 PharmAssist[27925:1197718] [logging] misuse at line 89232 of [378230ae7f]
Error binding strength.
2019-11-20 09:32:18.381835+0000 PharmAssist[27925:1197718] [logging] API called with NULL prepared statement
2019-11-20 09:32:18.381933+0000 PharmAssist[27925:1197718] [logging] misuse at line 88645 of [378230ae7f]
Message from debugger: Terminated due to signal 15

Answer 1

更正您的数据库和表名