@@ -761,17 +761,16 @@ Query OK, 1 row(s) in set (0.000141s)
you see sample code here: [JDBC example](https://github.com/taosdata/TDengine/tree/develop/tests/examples/JDBC)
## FAQ
- Why does not addBatch and executeBatch provide a performance benefit for executing "batch writes/updates"?
**Cause**:In TDengine's JDBC implementation, SQL statements submitted through the addBatch method are executed in the order in which they are added. This method does not reduce the number of interactions with the server and does not improve performance.
**Answer**：1. Concatenate multiple values in an INSERT statement; 2. Use multi-threaded concurrent insertion; 3. Use the parameter-binding to write
- java.lang.UnsatisfiedLinkError: no taos in java.library.path
**Cause**：The application program cannot find Library function *taos*
**Answer**：Copy `C:\TDengine\driver\taos.dll` to `C:\Windows\System32\` on Windows and make a soft link through `ln -s /usr/local/taos/driver/libtaos.so.x.x.x.x /usr/lib/libtaos.so` on Linux.
- java.lang.UnsatisfiedLinkError: taos.dll Can't load AMD 64 bit on a IA 32-bit platform
**Cause**：Currently TDengine only support 64bit JDK
**Answer**：re-install 64bit JDK.
- For other questions, please refer to [Issues](https://github.com/taosdata/TDengine/issues)
tdSql.query(f'select {table_name_sub1},{table_name_sub2},{table_name_sub3},{table_name_sub4},{table_name_sub5},{table_name_sub6},{table_name_sub7},{table_name_sub8},{table_name_sub9} from {table_name} where tbname in ("{table_name_sub1}","{table_name_sub2}","{table_name_sub3}","{table_name_sub4}","{table_name_sub5}","{table_name_sub6}","{table_name_sub7}","{table_name_sub8}","{table_name_sub9}") and ts >= "1980-01-01 00:00:00.000"')
this test case is an test case for unexpectd error for taosd work error ,it maybe caused by ;
'''
return
defrun(self):
tdSql.prepare()
tdSql.execute("create database if not exists testdb keep 36500;")
tdSql.execute("use testdb;")
tdSql.execute("create stable st (ts timestamp , id int , value double) tags(hostname binary(10) ,ind int);")
foriinrange(self.num):
tdSql.execute("insert into sub_%s using st tags('host_%s' , %d) values (%d , %d , %f );"%(str(i),str(i),i*10,self.ts+100*i,i*2,i+10.00))
tdSql.execute("insert into sub_%s using st tags('host_%s' , %d) values (%d , %d , %f );"%(str(i),str(i),i*10,self.ts+200*i,i*2,i+10.00))
tdSql.execute("insert into sub_%s using st tags('host_%s' , %d) values (%d , %d , %f );"%(str(i),str(i),i*10,self.ts+300*i,i*2,i+10.00))
tdSql.execute("insert into sub_%s using st tags('host_%s' , %d) values (%d , %d , %f );"%(str(i),str(i),i*10,self.ts+10000*i,i*2,i+10.00))
cfg_path=self.getcfgPath()
print(cfg_path)
tdSql.execute('select elapsed(ts,10s) from testdb.st where ts>=\"2015-01-01 00:00:00.000\" and ts < \"2015-01-01 00:10:00.000\" session(ts,1d) group by tbname;')# session not support super table
taos_cmd1="taos -c %s -s 'select elapsed(ts,10s) from testdb.st where ts>=\"2015-01-01 00:00:00.000\" and ts < \"2015-01-01 00:10:00.000\" session(ts,1d) group by tbname;' "%(cfg_path)
sql='select * from stable_1 where t_smallint between 0 and 32767 and t_float between 0 and 3.4E38 and t_nchar is not null and q_smallint between 0 and 32767 and q_nchar is not null and t_binary is not null and q_tinyint is not null and ts < now +1s order by ts ;;;'
tdSql.execute("create table db.`%s` as select avg(`%s`) from db.`%s` where ts > now interval(1m) sliding(30s);"%(self.cr_tb1,self.col_bigint,self.stb1))
tdSql.query("show db.tables like 'create_table_%' ")
tdSql.checkRows(1)
print("==============drop\ add\ change\ modify column or tag")
print("==============drop==============")
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_ts))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(21)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_double))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(20)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_float))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(19)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_nchar))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(18)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_binary))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(17)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_bool))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(16)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_tinyint))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(15)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_smallint))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(14)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_bigint))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(13)
tdSql.execute("ALTER TABLE db.`%s` DROP TAG `%s`; "%(self.stb1,self.tag_int))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(12)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_ts))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_9(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(11)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_double))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_8(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(10)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_float))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_7(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(9)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_nchar))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_6(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(8)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_binary))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_5(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(7)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_bool))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_4(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(6)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_tinyint))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_3(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(5)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_smallint))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_2(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(4)
tdSql.execute("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_bigint))
sql=" select * from db.`%s`; "%self.stb1
datacheck=self.table1_checkall_1(sql)
tdSql.query("describe db.`%s` ; "%self.tb1)
tdSql.checkRows(3)
tdSql.error("ALTER TABLE db.`%s` DROP COLUMN `%s`; "%(self.stb1,self.col_int))
sql=" select * from db2.`%s`; "%self.regular_table
datacheck=self.table1_checkall(sql)
tdSql.checkRows(2)
sql=" select * from db2.`%s` where `%s`=1 and `%s`=2 and `%s`=3 and `%s`=4 and `%s`='True' and `%s`=6 and `%s`=7 and `%s`=8 and `%s`=9 and `%s`=10; " \
