Question

我试图创建一个进度条，检查用户是否已将数据填充到数据库中。

到目前为止，我已经做到了，但是有没有更短的方法呢？此外，我在MYSQL工作台上收到一条警告消息，说

“选择对于此服务器版本在此位置无效，期望：'（'，

SELECT * FROM userCertificate 
WHERE certificatename IS NOT NULL 
AND organization IS NOT NULL 
AND location IS NOT NULL 
AND startdate IS NOT NULL;

Answer 1

您可以将COALESCE函数用于多列

class User : MyType {
  val address: Address? = null
  val company: Company? = null
  ...
}

class Address : MyType {
  val city: String? = null
}

class Company : MyType {
  val name: String? = null
}

var properties: MutableMap<String, Collection<KProperty1<Any, *>>>? = mutableMapOf()

fun init() {
    fillPropertiesMap(User::class.java)
}

private inline fun <reified T : Any> fillPropertiesMap(clazz: Class<T>) {
    val prop = clazz.kotlin.memberProperties
            .filter { it.visibility == KVisibility.PUBLIC } as Collection<KProperty1<Any, *>>
    fill(clazz as Class<Any>, prop)
}

fun fill(clazz: Class<Any>, props: Collection<KProperty1<Any, *>>) {
    properties[clazz.simpleName] = props
    props.forEach()
    { prop ->
        if (isMyCustomType(prop)) { 
            fillPropertiesMap(prop.????) . // how get class from KProperty1 for Address.class and Company.class
        }
    }
}

如何检查表中是否有多列为空

1 个答案: