SQLITE bulk UPDATE语句

Question

我想执行许多这样的SQL UPDATE语句：

UPDATE cityd SET time_zone='-7.000000' WHERE locId = 173567;
UPDATE cityd SET time_zone='-8.000000' WHERE locId = 173568;
UPDATE cityd SET time_zone='-6.000000' WHERE locId = 173569;
UPDATE cityd SET time_zone='-5.000000' WHERE locId = 173570;
UPDATE cityd SET time_zone='-6.000000' WHERE locId = 173571;

我想优化事务时间，所以我需要使用BEGIN TRANSACTION/COMMIT对。如何在SQLtite管理器中用Syntax编写？

编辑:当我在事务管理器中使用标准语法时，我收到这个错误消息："SQLiteManager: BEGIN TRANSACTION；[ cannot start a transaction in a SQLite“

Answer 1

根据SQL Documention，CASE有两种受支持的语法

CASE x WHEN w1 THEN r1 WHEN w2 THEN r2 ELSE r3 END

CASE WHEN x = w1 THEN r1 WHEN x = w2 THEN r2 ELSE r3 END

因此，您的多个UPDATE语句可以进一步简化为

UPDATE  cityd
SET     time_zone = CASE locId
                        WHEN 173567 THEN '-7.000000'
                        WHEN 173568 THEN '-8.000000'
                        WHEN 173569 THEN '-6.000000'
                        WHEN 173570 THEN '-5.000000'
                        WHEN 173571 THEN '-6.000000'
                    END
WHERE   locId IN (173567, 173568, 173569, 173570, 173571)

Answer 2

BEGIN TRANSACTION;
.....YOUR SQL Statements here

COMMIT;