String sql = "select count(*) as dd from zbn_computer ";
results = stmt.executeQuery(sql);
計算count的值:
int count;
if(results.next()){
count = results.getInt(1);
}
String sql = "select count(*) as dd from zbn_computer ";
results = stmt.executeQuery(sql);
計算count的值:
int count;
if(results.next()){
count = results.getInt(1);
}
數據庫備份和恢復 一、數據庫的備份 備份的類型以及瞭解 物理備份:1.冷備份(脫機備份):數據庫處於關閉狀態,直接打包數據庫文件 特點:備份速度快,回覆時簡單 2.熱