不透明指针错误 Swift 3.1

Question

我在使用 Swift 3.1 将外国字符和国际字符插入或更新到 SQLite 数据库时遇到问题。因此，我尝试在下面添加 UTF8，但是运行出现错误“无法将类型 'string' 的值转换为预期的参数类型 'OpaquePointer!'”。

我很困惑，不知道去哪里找。

func saveDiveDetails (_ dives: Dives) -> Int32 {
    let diveLog = AppDelegate.getDLDatabase()

    let diveBuddy = diveBuddyTextField.text ?? ""
    let diveMaster = diveBuddyTextField.text ?? ""
    let boatName = diveBuddyTextField.text ?? ""
    let diveCenter = diveBuddyTextField.text ?? ""
    let boatOperator = diveBuddyTextField.text ?? ""
    let city = diveBuddyTextField.text ?? ""
    let country = diveBuddyTextField.text ?? ""
    let bodyOfWater = diveBuddyTextField.text ?? ""
    let tripName = diveBuddyTextField.text ?? ""
    var statement: OpaquePointer? = nil

    let update:String = String(format: "UPDATE Dives SET dive_buddy = ?, dive_master = ?, boatName_name = ?, diveCenter_name = ?, boatOperator_name = ?, diveCity_name = ?, bodyOfWater_name = ?, diveCountry_name = ?, tripName_name = ? WHERE id = %d")

    if(sqlite3_prepare_v2(self.dlDatabase.database, update, -1, &statement, nil) == SQLITE_OK){
        sqlite3_bind_text(update, 0, diveBuddy.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 1, diveMaster.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 2, boatName.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 3, diveCenter.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 4, boatOperator.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 5, city.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 6, bodyOfWater.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 7, country.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_text(update, 8, tripName.cString(using: String.Encoding.utf8), -1, SQLITE_TRANSIENT)
        sqlite3_bind_int(update, 9, self.diveNumber)
    }

    sqlite3_prepare_v2(self.dlDatabase.database, update, -1, &statement, nil)
    sqlite3_bind_int(statement, 1, Int32(self.diveNumber));
    if sqlite3_step(statement) == SQLITE_DONE {

        print("SQLite saved")
    }
    else {
        let errorMessage = String.init(validatingUTF8: sqlite3_errmsg(dlDatabase.database))!
        print("update failed! \(errorMessage)")
    }
    sqlite3_finalize(statement)
}

我每次都在搜索，但找不到对此类错误的引用。

Answer 1

您不需要将 Swift 字符串转换为 C 字符串：

sqlite3_bind_text(update, 1, diveMaster, -1, SQLITE_TRANSIENT)

此外，请注意：sqlite3_bind_xxx 函数接受基于 1 的索引：sqlite3_bind_text(update, 0, ...) 无效。参见 https://sqlite.org/c3ref/bind_blob.html

参考：https://github.com/groue/GRDB.swift/blob/v0.106.2/GRDB/Core/Statement.swift#L162

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