例如:向数据库中插入100万条数据,在默认的情况下如果仅仅是执行
sqlite3_exec(db,“insert into name values ‘lxkxf',‘24'; ”,&zErrMsg);
将会重复的打开关闭数据库文件100万次,所以速度当然会很慢。因此对于这种情况我们应该使用“事务”。
具体方法如下:在执行sql语句之前和sql语句执行完毕之后加上
rc = sqlite3_exec(db,"BEGIN;",&zErrMsg);
//执行sql语句
rc = sqlite3_exec(db,"COMMIT;",&zErrMsg);
sqlite3_exec(db,“insert into name values ‘lxkxf',‘24'; ”,&zErrMsg);
将会重复的打开关闭数据库文件100万次,所以速度当然会很慢。因此对于这种情况我们应该使用“事务”。
具体方法如下:在执行sql语句之前和sql语句执行完毕之后加上
rc = sqlite3_exec(db,"BEGIN;",&zErrMsg);
//执行sql语句
rc = sqlite3_exec(db,"COMMIT;",&zErrMsg);
测试1: 1000 INSERTs
CREATE TABLE t1(a INTEGER,b INTEGER,c VARCHAR(100));
INSERT INTO t1 VALUES(1,13153,'thirteen thousand one hundred fifty three');
INSERT INTO t1 VALUES(2,75560,'seventy five thousand five hundred sixty');
... 995 lines omitted
INSERT INTO t1 VALUES(998,66289,'sixty six thousand two hundred eighty nine');
INSERT INTO t1 VALUES(999,24322,'twenty four thousand three hundred twenty two');
INSERT INTO t1 VALUES(1000,94142,'ninety four thousand one hundred forty two');
sqlite 2.7.6:
13.061
sqlite 2.7.6 (nosync):
0.223
CREATE TABLE t1(a INTEGER,b INTEGER,c VARCHAR(100));
INSERT INTO t1 VALUES(1,13153,'thirteen thousand one hundred fifty three');
INSERT INTO t1 VALUES(2,75560,'seventy five thousand five hundred sixty');
... 995 lines omitted
INSERT INTO t1 VALUES(998,66289,'sixty six thousand two hundred eighty nine');
INSERT INTO t1 VALUES(999,24322,'twenty four thousand three hundred twenty two');
INSERT INTO t1 VALUES(1000,94142,'ninety four thousand one hundred forty two');
sqlite 2.7.6:
13.061
sqlite 2.7.6 (nosync):
0.223
测试2: 使用事务 25000 INSERTs
BEGIN;
CREATE TABLE t2(a INTEGER,c VARCHAR(100));
INSERT INTO t2 VALUES(1,59672,'fifty nine thousand six hundred seventy two');
... 24997 lines omitted
INSERT INTO t2 VALUES(24999,89569,'eighty nine thousand five hundred sixty nine');
INSERT INTO t2 VALUES(25000,94666,'ninety four thousand six hundred sixty six');
COMMIT;
sqlite 2.7.6:
0.914
sqlite 2.7.6 (nosync):
0.757
可见使用了事务之后却是极大的提高了数据库的效率。但是我们也要注意,使用事务也是有一定的开销的,所以对于数据量很小的操作可以不必使用,以免造成而外的消耗。
android中的方法,
解决方法:
添加事务处理,把5000条插入作为一个事务
dataBase.beginTransaction();//手动设置开始事务
//数据插入操作循环
dataBase.setTransactionSuccessful();//设置事务处理成功,不设置会自动回滚不提交
dataBase.endTransaction();//处理完成
public final intbulkInsert(Uriurl,ContentValues[]values)
Since:
API Level 1
Inserts multiple rows into a table at the given URL. This function make no guarantees about the atomicity of the insertions.