TimesTen也支持Pro*C接口,从编程的角度来看,除了连接字符串的指定外,其它和针对Oracle的开发几乎一样。
我们先来看一下Pro*C程序连接TimesTen的框架:
int main(int argc, char** argv)
{
// 连接数据库,可以用以下三种方法之一
// 法一
EXEC SQL CONNECT :user IDENTIFIED BY :pass USING :svc;
// 法二
EXEC SQL CONNECT :connstr;
// 法三
EXEC SQL CONNECT :user IDENTIFIED BY :pass USING :easyconnstr;
// 执行DDL
EXEC SQL CREATE TABLE a (a int);
// 执行DML
EXEC SQL INSERT INTO a values(12345);
// 断开连接
EXEC SQL COMMIT WORK RELEASE;
exit(0);
}
EXEC SQL CONNECT :user IDENTIFIED BY :pass USING :svc;
法1是最传统的方法,svc指定的service在tnsnames.ora中定义
EXEC SQL CONNECT :connstr;
法2是法1的一个变种,connstr的形式为”username/password@service”, service也是在tnsnames.ora中定义,例如
“tthr/timesten@tnssampledb_1122”;
EXEC SQL CONNECT :user IDENTIFIED BY :pass USING :easyconnstr;
法3有些特别,不用TNS协议,而是直接使用easy connect字符串。
easy connect的通用格式为[//]host[:port]/service_name:server[/instance]。
TimesTen用的没这么复杂,简化的格式为hostname/DSN:driver, driver为timesten_client 或 timesten_direct,例如:
“localhost/sampledb_1122:timesten_direct”;
我还是建议使用TNS,TNS相当于为应用加了一层虚拟化接口,变动接口时,可以不用改源程序,比较灵活。
首先,预编译,是将.pc程序转化为.c程序
$ proc iname=helloworld.pc
Pro*C/C++: Release 11.2.0.2.0 - Production on Thu Jul 14 07:31:58 2016
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
System default option values taken from: /u01/app/oracle/product/11.2.0/dbhome_1/precomp/admin/pcscfg.cfg
$ ls -l helloworld.c
-rw-rw-r-- 1 oracle oracle 6678 Jul 14 07:31 helloworld.c
export INSTANT_CLIENT=$TT_HOME/ttoracle_home/instantclient_11_2
$ gcc -c helloworld.c -I $INSTANT_CLIENT/sdk/include
$ ll helloworld.o
-rw-rw-r-- 1 oracle oracle 5904 Jul 14 08:17 helloworld.o
$ gcc -o helloworld helloworld.o -L $INSTANT_CLIENT -lclntsh
$ ll helloworld
-rwxrwxr-x 1 oracle oracle 10446 Jul 14 08:18 helloworld
在此阶段定义了INSTANT_CLIENT,所谓instant client,就是一个简版的oracle client。
Oracle Instant Client is a light-weight software which helps to run OCI, OBDBC, Pro*C, JDBC without installing full Oracle client.
这就很好理解TimesTen自带的sqlplus可以连接Oracle数据库了。
这个程序的逻辑和之前的 极简Java连接TimesTen程序 是一样的。
$ ./helloworld
Command> select * from a;
< 12345 >
[oracle@timesten-hol proc]$ ./helloworld
ORACLE error--
ORA-00955: TT2207: Table A already exists -- file "plittddl.c", lineno 737, procedure "plittCreate"
Command> drop table a;
Command> select * from a;
< 12345 >
$ ./helloworld
Command> select * from a;
< 12345 >
Pro*C可以很简单的连接TimesTen, 和连接Oracle没有区别,不过我还是更建议不用 Pro*C,不伦不类的。
要性能,你可以用C,要简单和灵活性,你就用Java好了。
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sqlda.h>
#include <sqlcpr.h>
void sql_error(char *msg);
int main(int argc, char** argv)
{
char user[32] = "tthr";
char pass[32] = "timesten";
char svc[32] = "tnssampledb_1122";
char connstr[128] = "tthr/timesten@tnssampledb_1122";
char easyconnstr[128] = "localhost/sampledb_1122:timesten_direct";
EXEC SQL WHENEVER SQLERROR DO sql_error("ORACLE error--\n");
// EXEC SQL CONNECT :user IDENTIFIED BY :pass USING :svc;
EXEC SQL CONNECT :connstr;
// EXEC SQL CONNECT :user IDENTIFIED BY :pass USING :easyconnstr;
EXEC SQL CREATE TABLE a (a int);
EXEC SQL INSERT INTO a values(12345);
EXEC SQL COMMIT WORK RELEASE;
exit(0);
}
void sql_error(char *msg)
{
char err_msg[128];
size_t buf_len, msg_len;
EXEC SQL WHENEVER SQLERROR CONTINUE;
printf("\n%s\n", msg);
buf_len = sizeof (err_msg);
sqlglm((unsigned char *) err_msg, &buf_len, &msg_len);
printf("%.*s\n", (int) msg_len, err_msg);
EXEC SQL ROLLBACK RELEASE;
exit(EXIT_FAILURE);
}
tnssampledb_1122 =(DESCRIPTION=(CONNECT_DATA = (SERVICE_NAME = sampledb_1122)(SERVER = timesten_direct)))
这个是缺省安装自动产生的DSN,没有做修改
[sampledb_1122]
Driver=/home/oracle/TimesTen/tt1122/lib/libtten.so
DataStore=/home/oracle/TimesTen/tt1122/info/DemoDataStore/sampledb_1122
PermSize=40
TempSize=32
PLSQL=1
DatabaseCharacterSet=US7ASCII
SHELL=/bin/sh
TT_MVL_LINUX = 0
INSTDIR = /home/oracle/TimesTen/tt1122
COMMDIR = $(INSTDIR)/quickstart/sample_code/common
TTORACLE_HOME = $(INSTDIR)/ttoracle_home/instantclient_11_2
OCIINCS = $(TTORACLE_HOME)/sdk/include
CC = gcc
PLATCFLAGS = -Os -finline-functions
LDFLAGS =
EXTRALIBS = -lpthread -lm -lrt
ifeq ($(TT_MVL_LINUX),1)
EXTRALIBS += -ldl -lnsl -lnnz11
endif
INCS = -I$(INSTDIR)/include -I$(COMMDIR) -I$(OCIINCS)
CSDEFS = -DTTCLIENTSERVER
CFLAGS = $(PLATDEFS) $(PLATCFLAGS) $(INCS)
TTLINK = -L$(INSTDIR)/lib -L$(TTORACLE_HOME) -Wl,-rpath,$(INSTDIR)/lib
ICLIBS = $(TTLINK) -lclntsh $(EXTRALIBS)
HELLOWORLD = helloworld
HELLOWORLDOBJS = helloworld.o
PROGS = $(HELLOWORLD)
C_FILES = helloworld.c
#
# Top level targets
#
all: $(PROGS)
clean:
rm -f $(PROGS) *.o *.lis $(C_FILES)
#
# Targets for building executables
#
$(HELLOWORLD): $(HELLOWORLDOBJS)
$(CC) -o $@ $(LDFLAGS) $(HELLOWORLDOBJS) $(ICLIBS)
#
# Target for building object files
#
.c.o:
$(CC) $(CFLAGS) -o $@ -c $<
#
# Targets for Oracle Pro*C Pre-compilation
#
helloworld.c: helloworld.pc
@proc include=$(COMMDIR) iname=helloworld.pc config=pcscfg.cfg
在连接串中可以不指定服务,如下面的形式:
EXEC SQL CONNECT :user IDENTIFIED BY :pass
然后在环境变量中指定数据库名,环境变量的值既可以是TNS名,也可以是easy connect字符串。
环境变量的名字在Unix/Linux下是TWO_TASK,在Windows下是LOCAL。
如下例. 先测试TNS名:
[oracle@timesten-hol proc]$ unset TWO_TASK
[oracle@timesten-hol proc]$ ./helloworld
ORACLE error--
ORA-00955: name is already used by an existing object
$ export TWO_TASK=tnssampledb_1122
$ ./helloworld
Command> select * from a;
< 12345 >
Command> drop table a;
再测试easy connect 字符串:
$ export TWO_TASK='localhost/sampledb_1122:timesten_direct'
$ echo $TWO_TASK
localhost/sampledb_1122:timesten_direct
$ ./helloworld
Command> select * from a;
< 12345 >