ecpg 编译 postgresql 程序测试。

有关 ecpg 的功能方面的内容，请自行查阅 postgresql 手册。

测试建库语句：

create database sampledb;

测试表建表语句：

create table item_info (
      km_code        varchar(9),
      org_id         varchar(19),
      km_name        varchar(33),
      km_level       int2,
      km_code_parent varchar(9),
      jd_type        int2,
      km_attr        int2,
      data_dt        date,
      constraint pk_item_info primary key(km_code)
)

建立连接数据库测试：pg_connect.pgc

#include <stdio.h>
#include <stdlib.h>

int main ( void )
{
EXEC SQL BEGIN DECLARE SECTION;
char *target="sampledb@192.168.137.208:5432";
char *user="postgres";
char *passwd="postgres";
EXEC SQL END DECLARE SECTION;


        exec sql connect to :target user :user using :passwd;

        printf("%s\n",target);

        if (sqlca.sqlcode == 0 )
                printf("connect sucesess  ... \n");
        else {
                printf("connect faild ... ... \n");
                printf( " sqlca.sqlcode = %d \n",sqlca.sqlcode );
        }

        exit(0);
}

插入数据测试：pg_insert.pgc

#include <stdio.h>
#include <stdlib.h>

int main ( void )
{
        EXEC SQL BEGIN DECLARE SECTION;
        char *target="sampledb@192.168.137.208:5432";
        char *user="postgres";
        char *passwd="postgres";

        char    km_code[9] = "1909";
        char    org_id[19] = "8001";
        char    km_name[33] = "bbbb";
        int km_level = 1;
        char    km_code_parent[9] = "0000";
        int jd_type = 1;
        int km_attr = 1;
        char    data_dt[11] = "2020-12-31";


        EXEC SQL END DECLARE SECTION;


        exec sql connect to :target user :user using :passwd;

        printf("%s\n",target);

        if (sqlca.sqlcode != 0 ) {
                printf("connect faild ... ... \n");
                printf( " sqlca.sqlcode = %d \n",sqlca.sqlcode );
                exit(0);
        }

        exec sql begin;
        exec sql insert into item_info ( km_code,org_id, km_name , km_level , km_code_parent , jd_type , km_attr , data_dt ) values (:km_code , :org_id , :km_name , :km_level, :km_code_parent, :jd_type, :km_attr, :data_dt ) ;
        if ( sqlca.sqlcode == 0 ) {
                exec sql commit;
                printf (" insert into item_info ok \n");
        } else {
                printf (" insert into item_info err , sqlca.sqlcode = %d \n" , sqlca.sqlcode );
                exec sql rollback;
        }
        exit(0);
}

检索数据 pg_select.pgc

#include <stdio.h>
#include <stdlib.h>

int main ( void )
{
        EXEC SQL BEGIN DECLARE SECTION;
        char *target="sampledb@192.168.137.208:5432";
        char *user="postgres";
        char *passwd="postgres";

        char    km_code[9];
        char    org_id[19];
        char    km_name[33];
        int km_level;
        char    km_code_parent[9];
        int jd_type;
        int km_attr;
        char    data_dt[11];


        EXEC SQL END DECLARE SECTION;


        exec sql connect to :target user :user using :passwd;

        printf("%s\n",target);

        if (sqlca.sqlcode != 0 ) {
                printf("connect faild ... ... \n");
                printf( " sqlca.sqlcode = %d \n",sqlca.sqlcode );
                exit(0);
        }

        exec sql select km_code,org_id, km_name , km_level , km_code_parent , jd_type , km_attr , data_dt
                into :km_code , :org_id , :km_name , :km_level, :km_code_parent, :jd_type, :km_attr, :data_dt from item_info while limit 1;

        if ( sqlca.sqlcode == 0 )
        {
                printf(" km_code        = %s \n",km_code);
                printf(" org_id         = %s \n",org_id);
                printf(" km_name        = %s \n",km_name);
                printf(" km_level       = %d \n",km_level);
                printf(" km_code_parent = %s \n",km_code_parent);
                printf(" jd_type        = %d \n",jd_type);
                printf(" km_attr        = %d \n",km_attr);
                printf(" data_dt        = %s \n",data_dt);
        }
        exit(0);
}

Makefile 文件：

TARGET  = pg_connect pg_select pg_insert

CC = gcc
CFLAGS = -g -O2 -c -fPIC -DDEBUG

ECPG = ecpg -c

AR = ar -rcvl
RANLIB = ranlib

INCLDIR = -I. -I/opt/PostgreSQL/11.10/include
LIBDIR = -L. -L$(HOME)/lib -L/opt/PostgreSQL/11.10/lib
LIBS = -lecpg

OBJ =

all:$(TARGET)

clean:
rm -f $(TARGET) *.o core.* .*.swp

pg_connect:pg_connect.o
$(CC) -o $@ $^ $(LIBDIR) $(LIBS)

pg_select:pg_select.o
$(CC) -o $@ $^ $(LIBDIR) $(LIBS)

pg_insert:pg_insert.o
$(CC) -o $@ $^ $(LIBDIR) $(LIBS)

# ################################################################################

.SUFFIXES:
.SUFFIXES:.c .o .pgc

.pgc.c:
$(ECPG) $(INCLUDE) $<

.c.o:
$(CC) $(CFLAGS) $(INCLDIR) $<

需要注意：
以上参个程序编译完成后，运行时需要 /usr/lib/libecpg.so.6 和 /usr/lib/libpgtypes.so.3 这两个动态连接库。
切记！切记！