[英]How to check whether a value is already in an arraylist before inserting it in Java?
[英]android how to check in java before saving record the string value already exist in mysql data base
我有 6 個字符串值,但我想檢查記錄的一個字符串,即 MySQL 數據庫中記錄之前的值。
我有一個點,我想在這里檢查java是PHP。
$billno = $_POST["billno"];
$date = $_POST["date"];
$customer_name = $_POST["customer_name"];
$customer_number = $_POST["customer_number"];
$remark = $_POST["remark"];
$amount = $_POST["amount"];
我想插入數據,還想檢查 customer_number 是否已經存在。
將客戶編號列設置為在 Mysql DB 中唯一。 嘗試將重復的客戶編號插入數據庫時,它會給出錯誤響應。
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