【原创】OCILIB操作bfile字段

1、目录知识

(1)、基于服务端 vs 基于客户端

文件的路径都是相对于服务端目录的路径。

(2)、如何创建一个目录对象？

为了创建目录，必须具有DBA角色或者赋予了CREATE ANY DIRECTORY权限。

示例：

Window平台

CONNECT system/manager 

CREATE OR REPLACE DIRECTORY my_dir as ‘D:\DataPump‘; 

CREATE OR REPLACE DIRECTORY my_logdir as ‘E:\logs‘; 

GRANT read, write ON DIRECTORY my_dir TO scott; 

GRANT read, write ON DIRECTORY my_logdir TO scott;

Unix平台

CONNECT system/manager 

GRANT CREATE ANY DIRECTORY TO scott; 

CONNECT scott/tiger 

CREATE OR REPLACE DIRECTORY my_dir as ‘/usr/DataPump‘; 

CREATE OR REPLACE DIRECTORY my_logdir as ‘/usr/logs‘;

如果普通用户被赋予了CREATE ANY DIRECTORY权限，那么用户就自动具备目录的READ和WRITE权限。

注意：CREATE DIRECTORY语句不会创建磁盘的真实目录，如果目录是无效的，数据泵作业会报错：

ORA-39002: invalid operation 

ORA-39070: Unable to open the log file. 

ORA-29283: invalid file operation 

ORA-06512: at "SYS.UTL_FILE", line 475 

ORA-29283: invalid file operation

(3)、如何查询可用的目录？

可以使用如下SQL查询具有READ和WRITE权限的目录：

SELECT directory_name, grantee, privilege 

FROM user_tab_privs t, all_directories d 

WHERE t.table_name(+)=d.directory_name   

ORDER BY 1,2,3;

2、建测试表

create table bfile_test

(

code number(6),

value bfile

)

3、代码(由ocilib demo增加注释而来)

#include "ocilib.h"

int main(void)
{
    OCI_Connection *cn;
    OCI_Statement *st;
    OCI_Resultset *rs;
    OCI_File *file;
    char buffer[256];
    int n;

     if (!OCI_Initialize(NULL, NULL, OCI_ENV_DEFAULT | OCI_ENV_CONTEXT))
    {
        printf("Error OCI_Initialize\n");
        return -1;
    }

    cn = OCI_ConnectionCreate("hisd", "ha2", "peidian", OCI_SESSION_DEFAULT);
    if (!cn)
    {
        printf("Error OCI_ConnectionCreate\n");
        return -1;
    }

    st = OCI_StatementCreate(cn);
    if (!st)
    {
        printf("Error OCI_StatementCreate\n");
        return -1;
    }

    file = OCI_FileCreate(cn, OCI_CFILE);
    if (!file)
    {
        printf("Error OCI_FileCreate\n");
        return -1;
    }

    if (!OCI_FileSetName(file, "MYDIR", "bbbb.txt"))
    {
        printf("Error OCI_FileSetName\n");
        return -1;
    }

    /* check if faile exists */
    if (OCI_FileExists(file))
    {
         printf("file size : %d\n", OCI_FileGetSize(file));
         printf("file dir  : %s\n", OCI_FileGetDirectory(file));
         printf("file name : %s\n", OCI_FileGetName(file));
    }else
    {
        printf("Error OCI_FileExists\n");
        return -1;
    }

    /* bind for inserting into table */

    if(!OCI_Prepare(st, "insert into BFILE_TEST(code, value) values (1, :bfile)"))
    {
        printf("Error OCI_Prepare\n");
        return -1;
    }

    if(!OCI_BindFile(st, ":bfile", file))
    {
        printf("Error OCI_BindFile\n");
        return -1;
    }

    if(!OCI_Execute(st))
    {
        printf("Error OCI_Execute\n");
        return -1;
    }

    if(!OCI_Commit(cn))
    {
        printf("Error OCI_Commit\n");
        return -1;
    }

    /* free local file object */

    OCI_FileFree(file);

     printf("insert OK\n");

#if 0
    /* fetch bfile data from table */
    OCI_ExecuteStmt(st, "select code, value from BFILE_TEST");
    rs = OCI_GetResultset(st);
    while (OCI_FetchNext(rs))
    {
        file = OCI_GetFile(rs, 2);

        OCI_FileOpen(file);

        printf("file size  %d\n", OCI_FileGetSize(file));
        printf("file dir   %s\n", OCI_FileGetDirectory(file));
        printf("file name  %s\n", OCI_FileGetName(file));

        while (n = OCI_FileRead(file, buffer, sizeof(buffer)-1))
        {
            buffer[n] = 0;
            printf(buffer);
        }

        OCI_FileClose(file);
    }

    OCI_Cleanup();
#endif

    return EXIT_SUCCESS;
}