[英]Multiple Statement in single connection
我編寫了在單個連接中運行多個語句的代碼。 第一條語句將檢索要循環並由第二條語句使用的 ID,然后獲得所需的輸出。 例如:
String sql1 = "SELECT ID FROM __TestParent WHERE Status = 'S'";
try (
Connection conn = DbConnector.getConnection();
Statement s = conn.createStatement();
Statement s2 = conn.createStatement();
ResultSet rs = s.executeQuery(sql1)
) {
while(rs.next()) {
String id = String.valueOf(rs.getInt("ID"));
String sql2 = "SELECT Description FROM __TestChild WHERE FK = " + id;
try (
ResultSet rs2 = s2.executeQuery(sql2)
) {
while(rs2.next())
Util.printLog("INFO",rs2.getString("Description"));
}catch(SQLTimeoutException sqltoex){
Util.printLog("SEVERE",sqltoex);
}catch(SQLException sqlex){
Util.printLog("SEVERE",sqlex);
}
}
}catch(SQLTimeoutException sqltoex){
Util.printLog("SEVERE",sqltoex);
}catch(SQLException sqlex){
Util.printLog("SEVERE",sqlex);
}
代碼運行良好,輸出符合預期。 我想知道的是:
謝謝。
您實際上可以使用單個查詢和結果集執行您想要的操作:
SELECT c.Description
FROM __TestChild c
INNER JOIN __TestParent p
ON c.FK = p.ID
WHERE p.Status = 'S';
代碼:
String sql = "SELECT c.Description FROM __TestChild c ";
sql += " INNER JOIN __TestParent p ON c.FK = p.ID ";
sql += "WHERE p.Status = 'S'";
try (
Connection conn = DbConnector.getConnection();
Statement s = conn.createStatement();
ResultSet rs = s.executeQuery(sql)
) {
while(rs.next()) {
Util.printLog("INFO", rs.getString("Description"));
}
} catch(SQLTimeoutException sqltoex) {
Util.printLog("SEVERE",sqltoex);
} catch(SQLException sqlex) {
Util.printLog("SEVERE",sqlex);
}
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