本文介绍了 DBMS_CLOUD 包的基本用法。
自治数据库中引入了 DBMS_CLOUD 包，以提供一种与数据库中的对象存储进行交互的简单方法。它可用于版本 19c 和 21c 的本地安装。 它同样适用于 AWS S3 存储 buckets 或 Oracle Cloud Object Storage 存储 buckets。
先决条件
本文中的大多数示例都使用 DBMS_CLOUD 包的本地安装，但某些功能似乎只能在自治数据库上正常工作，过程中我将强调这些限制出现的地方。
DBMS_CLOUD 包默认存在于自治数据库中，它未安装在 Oracle 19c 或 21c 安装中，因此必须手动安装，此 MOS 说明中描述了安装。
可以参考下方的安装示例：
对于某些示例，我们需要一个对象存储 buckets。这可以是 Oracle Cloud Object Store 存储 buckets 或 AWS S3 存储 buckets。以下文章介绍了如何创建 Oracle Cloud Object Store 存储 buckets。
安装
我们创建一个测试用户，确保用户可以创建凭据，并授予其访问 DBMS_CLOUD 包的权限。
conn sys/SysPassword1@//localhost:1521/pdb1 as sysdba
--drop user testuser1 cascade;
create user testuser1 identified by testuser1 quota unlimited on users;
grant connect, resource to testuser1;
grant create credential to testuser1;
grant execute on dbms_cloud to testuser1;
我们需要一个本地目录对象来与数据库文件服务器上的文件进行交互，授予 test 用户和 C##CLOUD$SERVICE 用户访问此目录的权限。
create or replace directory tmp_files_dir as '/tmp/files';
grant read, write on directory tmp_files_dir to testuser1, C##CLOUD$SERVICE;
外部表功能需要访问名为 DATA_PUMP_DIR 的目录对象，因此在 PDB 中创建它并向测试用户授予读/写访问权限。
alter session set "_oracle_script"=TRUE;
create or replace directory data_pump_dir as '/u01/app/oracle/admin/cdb1/dpdump/';
alter session set "_oracle_script"=FALSE;
grant read, write on directory data_pump_dir to testuser1;
连接到测试用户并创建下表：
conn testuser1/testuser1@//localhost:1521/pdb1
create table emp (
empno number(4,0),
ename varchar2(10 byte),
job varchar2(9 byte),
mgr number(4,0),
hiredate date,
sal number(7,2),
comm number(7,2),
deptno number(2,0),
constraint pk_emp primary key (empno)
);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7369,'SMITH','CLERK',7902,to_date('17-DEC-80','DD-MON-RR'),800,null,20);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7499,'ALLEN','SALESMAN',7698,to_date('20-FEB-81','DD-MON-RR'),1600,300,30);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7521,'WARD','SALESMAN',7698,to_date('22-FEB-81','DD-MON-RR'),1250,500,30);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7566,'JONES','MANAGER',7839,to_date('02-APR-81','DD-MON-RR'),2975,null,20);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7654,'MARTIN','SALESMAN',7698,to_date('28-SEP-81','DD-MON-RR'),1250,1400,30);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7698,'BLAKE','MANAGER',7839,to_date('01-MAY-81','DD-MON-RR'),2850,null,30);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7782,'CLARK','MANAGER',7839,to_date('09-JUN-81','DD-MON-RR'),2450,null,10);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7788,'SCOTT','ANALYST',7566,to_date('19-APR-87','DD-MON-RR'),3000,null,20);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7839,'KING','PRESIDENT',null,to_date('17-NOV-81','DD-MON-RR'),5000,null,10);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7844,'TURNER','SALESMAN',7698,to_date('08-SEP-81','DD-MON-RR'),1500,0,30);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7876,'ADAMS','CLERK',7788,to_date('23-MAY-87','DD-MON-RR'),1100,null,20);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7900,'JAMES','CLERK',7698,to_date('03-DEC-81','DD-MON-RR'),950,null,30);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7902,'FORD','ANALYST',7566,to_date('03-DEC-81','DD-MON-RR'),3000,null,20);
insert into emp (empno,ename,job,mgr,hiredate,sal,comm,deptno) values (7934,'MILLER','CLERK',7782,to_date('23-JAN-82','DD-MON-RR'),1300,null,10);
commit;
本文中所有 SQL 操作均由测试用户执行，除非特殊说明。
conn testuser1/testuser1@//localhost:1521/pdb1
对象存储 URI
对于本文中的许多示例，我们使用对象存储 URI。对于 Oracle Cloud，URI 可以采用这些形式之一。
https://swiftobjectstorage.{region}.oraclecloud.com/v1/{namespace}/{bucket}/{objectname}
https://objectstorage.{region}.oraclecloud.com/n/{namespace}/b/{bucket}/o/{objectname}本文主要使用 swiftobjectstorage URI，但两者都有效。 在本文的其余部分，我们将使用 swiftobjectstorage URI。
AWS S3 和 Azure blob 存储 URI 通常如下所示：
AWS S3: https://s3-{region}.amazonaws.com/{bucket}/{objectname}
Azure Blog Storage: https://{account}.blob.core.windows.net/{container}/{objectname}对象存储凭证
DBMS_CLOUD 包包含来自 DBMS_CREDENTIAL 包的过程的副本。这两个包可以互换使用，因为它们做同样的事情。
使用 CREATE_CREDENTIAL 过程为您的对象存储创建凭证。对于 Oracle 对象存储桶，我们使用我们的 Oracle Cloud 电子邮件和我们生成的身份验证令牌。
begin
dbms_cloud.create_credential (
credential_name => 'obj_store_cred',
username => 'me@example.com',
password => '{my-Auth-Token}'
) ;
end;
/
对于 AWS 存储 buckets，我们使用我们的 AWS 访问密钥和秘密访问密钥。
begin
dbms_cloud.create_credential (
credential_name => 'obj_store_cred',
username => 'my AWS access key',
password => 'my AWS secret access key'
);
end;
/
可以使用 USER_CREDENTIALS 视图显示有关凭证的信息。
column credential_name format a25
column username format a20
select credential_name,
username,
enabled
from user_credentials
order by credential_name;
CREDENTIAL_NAME USERNAME ENABL
------------------------- -------------------- -----
OBJ_STORE_CRED me@example.com TRUE
SQL>
DISABLE_CREDENTIAL 和 ENABLE_CREDENTIAL 过程分别禁用和启用凭据。
begin
dbms_credential.disable_credential('obj_store_cred');
dbms_credential.enable_credential('obj_store_cred');
end;/
UPDATE_CREDENTIALS 过程允许我们编辑凭证的属性。
begin
dbms_credential.update_credential(
credential_name => 'obj_store_cred',
attribute => 'username',
value => 'me@example.com');
dbms_credential.update_credential(
credential_name => 'obj_store_cred',
attribute => 'password',
value => '{my-Auth-Token}');
end;
/
DROP_CREDENTIAL 过程删除命名凭据。
begin
dbms_cloud.drop_credential(credential_name => 'obj_store_cred');
end;
/
以下示例需要有效凭据。
对象和文件
有几个例程可用于操作本地数据库文件系统上的文件和云对象存储中的对象。
在数据库服务器文件系统上创建一个文件。
mkdir -p /tmp/files
echo "This is a test file" > /tmp/files/test1.txt
我们使用 PUT_OBJECT 过程将文件从目录对象位置传输到云对象存储。
begin
dbms_cloud.put_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test1.txt',
directory_name => 'tmp_files_dir',
file_name => 'test1.txt');
end;
/
PUT_OBJECT 过程有一个重载，用于将 BLOB 的内容传输到对象存储。
declare
l_file blob;
begin
l_file := utl_raw.cast_to_raw('This is another test file');
dbms_cloud.put_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test2.txt',
contents => l_file);
end;
/
LIST_OBJECTS 表函数列出对象存储 URI 指向的位置中的对象。
set linesize 150
column object_name format a12
column checksum format a35
column created format a35
column last_modified format a35
select *
from dbms_cloud.list_objects(
credential_name => 'obj_store_cred',
location_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket');
OBJECT_NAME BYTES CHECKSUM CREATED LAST_MODIFIED
------------ ---------- ----------------------------------- ----------------------------------- -----------------------------------
test1.txt 20 5dd39cab1c53c2c77cd352983f9641e1 11-SEP-21 08.45.42.779000 AM +00:00
test2.txt 25 d0914057907f9d04dd9e68b1c1e180f0 11-SEP-21 08.45.54.148000 AM +00:00
SQL>
我们使用 GET_METADATA 函数返回有关特定对象的信息。
select dbms_cloud.get_metadata(
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test2.txt') as metadata
from dual;
METADATA
--------------------------------------------------------------------------------
{"Content-Length":25}
SQL>
我们使用 GET_OBJECT 过程将对象从云对象存储传输到目录对象位置。
begin
dbms_cloud.get_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test2.txt',
directory_name => 'tmp_files_dir',
file_name => 'test2.txt');
end;
/
有一个 GET_OBJECT 函数可以将对象从云对象存储传输到 BLOB。
declare
l_file blob;
begin
l_file := dbms_cloud.get_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test2.txt');
end;
/
DELETE_OBJECT 过程从云对象存储中删除对象。
begin
dbms_cloud.delete_object(
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test1.txt');
dbms_cloud.delete_object(
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/test2.txt');
end;
/
DELETE_FILE 过程从目录对象位置删除文件。
begin
dbms_cloud.delete_file(
directory_name => 'tmp_files_dir',
file_name => 'test1.txt');
dbms_cloud.delete_file(
directory_name => 'tmp_files_dir',
file_name => 'test2.txt');
end;
/
LIST_FILES 表函数列出指定 Oracle 目录对象指向的位置中的文件。 文档说它只支持映射到 Oracle 文件系统 (OFS) 或数据库文件系统 (DBFS) 文件系统的目录对象，所以我们不能将它用于常规文件系统。 它确实在自治数据库上提供的位置工作。
select *
from dbms_cloud.list_files(directory_name => 'data_pump_dir');
外部表
本节介绍基于云对象存储中的文件创建外部表。
CREATE_EXTERNAL_TABLE
我们使用以下内容创建一个名为“emp.dat”的文件并将其放入我们的对象存储中。 它是一个没有标题的管道分隔文件。
7369|"SMITH"|"CLERK"|7902|17-DEC-80|800||20
7499|"ALLEN"|"SALESMAN"|7698|20-FEB-81|1600|300|30
7521|"WARD"|"SALESMAN"|7698|22-FEB-81|1250|500|30
7566|"JONES"|"MANAGER"|7839|02-APR-81|2975||20
7654|"MARTIN"|"SALESMAN"|7698|28-SEP-81|1250|1400|30
7698|"BLAKE"|"MANAGER"|7839|01-MAY-81|2850||30
7782|"CLARK"|"MANAGER"|7839|09-JUN-81|2450||10
7788|"SCOTT"|"ANALYST"|7566|19-APR-87|3000||20
7839|"KING"|"PRESIDENT"||17-NOV-81|5000||10
7844|"TURNER"|"SALESMAN"|7698|08-SEP-81|1500|0|30
7876|"ADAMS"|"CLERK"|7788|23-MAY-87|1100||20
7900|"JAMES"|"CLERK"|7698|03-DEC-81|950||30
7902|"FORD"|"ANALYST"|7566|03-DEC-81|3000||20
7934|"MILLER"|"CLERK"|7782|23-JAN-82|1300||10
CREATE_EXTERNAL_TABLE 过程基于云对象存储中的文件创建名为 EMP_EXT 的外部表。
--drop table emp_ext;
begin
dbms_cloud.create_external_table(
table_name => 'emp_ext',
credential_name => 'obj_store_cred',
file_uri_list => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/emp.dat',
column_list => 'empno number(4),
ename varchar2(10),
job varchar2(9),
mgr number(4),
hiredate date,
sal number(7,2),
comm number(7,2),
deptno number(2)',
format => json_object('ignoremissingcolumns' value 'true', 'removequotes' value 'true')
);
end;
/
我们查询外部表，它从云对象存储中读取数据。
select * from emp_ext;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
SQL>
FORMAT 参数允许我们调整加载过程以适应数据文件内容。 可以在此处找到格式选项的完整列表，以下示例适用于 CSV 文件。
我们使用以下内容创建一个名为“emp.csv”的文件并将其放入我们的对象存储中。 它是一个带有标题行的 CSV 文件。
"EMPNO","ENAME","JOB","MGR","HIREDATE","SAL","COMM","DEPTNO"
7369,"SMITH","CLERK",7902,17-DEC-80,800,,20
7499,"ALLEN","SALESMAN",7698,20-FEB-81,1600,300,30
7521,"WARD","SALESMAN",7698,22-FEB-81,1250,500,30
7566,"JONES","MANAGER",7839,02-APR-81,2975,,20
7654,"MARTIN","SALESMAN",7698,28-SEP-81,1250,1400,30
7698,"BLAKE","MANAGER",7839,01-MAY-81,2850,,30
7782,"CLARK","MANAGER",7839,09-JUN-81,2450,,10
7788,"SCOTT","ANALYST",7566,19-APR-87,3000,,20
7839,"KING","PRESIDENT",,17-NOV-81,5000,,10
7844,"TURNER","SALESMAN",7698,08-SEP-81,1500,0,30
7876,"ADAMS","CLERK",7788,23-MAY-87,1100,,20
7900,"JAMES","CLERK",7698,03-DEC-81,950,,30
7902,"FORD","ANALYST",7566,03-DEC-81,3000,,20
7934,"MILLER","CLERK",7782,23-JAN-82,1300,,10
CREATE_EXTERNAL_TABLE 过程基于云对象存储中的文件创建名为 EMP_CSV_EXT 的外部表。
--drop table emp_csv_ext;
begin
dbms_cloud.create_external_table(
table_name => 'emp_csv_ext',
credential_name => 'obj_store_cred',
file_uri_list => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/emp.csv',
column_list => 'empno number(4),
ename varchar2(10),
job varchar2(9),
mgr number(4),
hiredate date,
sal number(7,2),
comm number(7,2),
deptno number(2)',
format => json_object('type' value 'csv', 'skipheaders' value '1')
);
end;
/
我们查询外部表，它从云对象存储中读取数据。
select * from emp_csv_ext;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
SQL>
VALIDATE_EXTERNAL_TABLE 过程允许我们检查外部表的有效性。
begin
dbms_cloud.validate_external_table('emp_csv_ext');
end;
/
CREATE_EXTERNAL_PART_TABLE
使用以下查询创建四个 CSV 文件：
set markup csv on quote on
set trimspool on linesize 1000 feedback off pagesize 0
spool /tmp/files/gbr1.txt
select 'GBR',
object_id,
owner,
object_name
from all_objects
where object_id <= 2000
and rownum <= 1000;
spool off
spool /tmp/files/gbr2.txt
select 'GBR',
object_id,
owner,
object_name
from all_objects
where object_id BETWEEN 2000 AND 3999
and rownum <= 1000;
spool off
spool /tmp/files/ire1.txt
select 'IRE',
object_id,
owner,
object_name
from all_objects
where object_id <= 2000
and rownum <= 1000;
spool off
spool /tmp/files/ire2.txt
select 'IRE',
object_id,
owner,
object_name
from all_objects
where object_id BETWEEN 2000 AND 3999
and rownum <= 1000;
spool off
set markup csv off
set trimspool on linesize 1000 feedback off pagesize 14
在上传文件之前，您可能需要稍微清理文件的开头和结尾。 将文件复制到对象存储：
begin
dbms_cloud.put_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/gbr1.txt',
directory_name => 'tmp_files_dir',
file_name => 'gbr1.txt');
end;
/
begin
dbms_cloud.put_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/gbr2.txt',
directory_name => 'tmp_files_dir',
file_name => 'gbr2.txt');
end;
/
begin
dbms_cloud.put_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/ire1.txt',
directory_name => 'tmp_files_dir',
file_name => 'ire1.txt');
end;
/
begin
dbms_cloud.put_object (
credential_name => 'obj_store_cred',
object_uri => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/ire2.txt',
directory_name => 'tmp_files_dir',
file_name => 'ire2.txt');
end;
/
CREATE_EXTERNAL_PART_TABLE 过程基于云对象存储中的文件创建名为 COUNTRY_PART_TAB_EXT 的外部分区表。
--drop table country_part_tab_ext;
begin
dbms_cloud.create_external_part_table(
table_name => 'country_part_tab_ext',
credential_name => 'obj_store_cred',
format => json_object('type' value 'csv', 'skipheaders' value '1'),
column_list => 'country_code varchar2(3),
object_id number,
owner varchar2(128),
object_name varchar2(128)',
partitioning_clause => 'partition by list (country_code) (
partition part_gbr values (''GBR'') location (
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/gbr1.txt'',
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/gbr2.txt''
),
partition part_ire values (''IRE'') location (
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/ire1.txt'',
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/ire2.txt''
)
)'
);
end;
/
我们查询外部表，它从云对象存储中读取数据。
select country_code, count(*) as amount
from country_part_tab_ext
group by country_code
order by country_code;
COU AMOUNT
--- ----------
GBR 2000
IRE 2000
SQL>
VALIDATE_EXTERNAL_PART_TABLE 过程允许我们检查外部分区表的有效性。
begin
dbms_cloud.validate_external_part_table('country_part_tab_ext');
end;
/
CREATE_HYBRID_PART_TABLE
CREATE_HYBRID_PART_TABLE 过程基于云对象存储中的文件创建一个名为 COUNTRY_HYBRID_PART_TAB_EXT 的外部混合分区表。
--drop table country_hybrid_part_tab_ext;
begin
dbms_cloud.create_hybrid_part_table(
table_name => 'country_hybrid_part_tab_ext',
credential_name => 'obj_store_cred',
format => json_object('type' value 'csv', 'skipheaders' value '1'),
column_list => 'country_code varchar2(3),
object_id number,
owner varchar2(128),
object_name varchar2(128)',
partitioning_clause => 'partition by list (country_code) (
partition part_gbr values (''GBR'') external location (
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/gbr1.txt'',
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/gbr2.txt''
),
partition part_ire values (''IRE'') external location (
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/ire1.txt'',
''https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/ire2.txt''
),
partition part_usa values (''USA'')
)'
);
end;
/
我们在常规分区中插入一行。
insert into country_hybrid_part_tab_ext values ('USA', 123, 'banana', 'banana');
commit;我们查询外部表，它从云对象存储中读取数据。
select country_code, count(*) as amount
from country_hybrid_part_tab_ext
group by country_code
order by country_code;
COU AMOUNT
--- ----------
GBR 2000
IRE 2000
USA 1
SQL>
VALIDATE_HYBRID_PART_TABLE 过程允许我们检查外部混合分区表的有效性。
begin
dbms_cloud.validate_hybrid_part_table('country_hybrid_part_tab_ext');
end;
/
COPY_DATA
COPY_DATA 过程允许我们将数据从云对象存储复制到现有表中。
我们使用以下内容创建一个名为“emp.csv”的文件并将其放入我们的对象存储中。 它是一个带有标题行的 CSV 文件。
"EMPNO","ENAME","JOB","MGR","HIREDATE","SAL","COMM","DEPTNO"
7369,"SMITH","CLERK",7902,17-DEC-80,800,,20
7499,"ALLEN","SALESMAN",7698,20-FEB-81,1600,300,30
7521,"WARD","SALESMAN",7698,22-FEB-81,1250,500,30
7566,"JONES","MANAGER",7839,02-APR-81,2975,,20
7654,"MARTIN","SALESMAN",7698,28-SEP-81,1250,1400,30
7698,"BLAKE","MANAGER",7839,01-MAY-81,2850,,30
7782,"CLARK","MANAGER",7839,09-JUN-81,2450,,10
7788,"SCOTT","ANALYST",7566,19-APR-87,3000,,20
7839,"KING","PRESIDENT",,17-NOV-81,5000,,10
7844,"TURNER","SALESMAN",7698,08-SEP-81,1500,0,30
7876,"ADAMS","CLERK",7788,23-MAY-87,1100,,20
7900,"JAMES","CLERK",7698,03-DEC-81,950,,30
7902,"FORD","ANALYST",7566,03-DEC-81,3000,,20
7934,"MILLER","CLERK",7782,23-JAN-82,1300,,10
我们截断本地 EMP 表并使用 COPY_DATA 过程从云对象存储重新加载数据。
truncate table emp;
begin
dbms_cloud.copy_data(
table_name => 'emp',
credential_name => 'obj_store_cred',
file_uri_list => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/emp.csv',
format => json_object('type' value 'csv', 'skipheaders' value '1')
);
end;
/
我们查询EMP表，可以看到数据已经加载完毕。
select * from emp;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
SQL>
与外部表示例类似，FORMAT 参数允许我们定制加载过程以适应数据文件内容。
Export Data
EXPORT_DATA 过程获取查询生成的数据，并以请求的格式将其导出到云对象存储。 这似乎不适用于 DBMS_CLOUD 包的本地版本，但适用于自治数据库。
begin
dbms_cloud.export_data (
credential_name => 'obj_store_cred',
file_uri_list => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/emp.json',
query => 'select * from emp',
format => '{"type" : "JSON"}'
);
end;
/
begin
dbms_cloud.export_data (
credential_name => 'obj_store_cred',
file_uri_list => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/emp.csv',
query => 'select * from emp',
format => '{"type" : "CSV"}'
);
end;
/
SODA Collections
Oracle 数据库可用作使用简单 Oracle 文档访问 (SODA) 的文档存储。 您可以在此处阅读有关 SODA 的信息。
我们创建一个名为“TestCollection1”的新集合。
set serveroutput on
declare
l_collection soda_collection_t;
begin
l_collection := dbms_soda.create_collection('TestCollection1');
if l_collection is not null then
dbms_output.put_line('Collection ID : ' || l_collection.get_name());
else
dbms_output.put_line('Collection does not exist.');
end if;
end;
/
Collection ID : TestCollection1
PL/SQL procedure successfully completed.
SQL>
使用以下内容创建一个名为“fruit.json”的文件并将其上传到您的云对象存储。
{"fruit": "banana"}COPY_COLLECTION 过程将数据从我们的云对象存储加载到集合中。
begin
dbms_cloud.copy_collection(
collection_name => 'TestCollection1',
credential_name => 'obj_store_cred',
file_uri_list => 'https://swiftobjectstorage.uk-london-1.oraclecloud.com/v1/my-namespace/ob-bucket/fruit.json',
format => json_object('unpackarrays' value 'true')
);
end;
/
我们可以使用以下查询查看集合中的数据。
select json_document
from "TestCollection1";
JSON_DOCUMENT
--------------------------------------------------------------------------------
{"fruit":"banana"}
SQL>
删除操作
许多 DBMS_CLOUD 操作会产生额外的文件（日志文件、坏文件、临时文件等）。 一旦操作完成，这些需要清理。 上面显示的几个过程具有返回操作 ID 值的重载，该值可与 DELETE_OPERATION 过程一起使用以清理额外的文件。 或者，可以使用 USER_LOAD_OPERATIONS 视图显示当前会话的操作。
SQL> desc user_load_operations
Name Null? Type
----------------------------------------------------- -------- ------------------------------------
ID NOT NULL NUMBER
TYPE NOT NULL VARCHAR2(128)
SID NOT NULL NUMBER
SERIAL# NOT NULL NUMBER
START_TIME TIMESTAMP(6) WITH TIME ZONE
UPDATE_TIME TIMESTAMP(6) WITH TIME ZONE
STATUS VARCHAR2(9)
OWNER_NAME VARCHAR2(128)
TABLE_NAME VARCHAR2(128)
PARTITION_NAME VARCHAR2(128)
SUBPARTITION_NAME VARCHAR2(128)
FILE_URI_LIST VARCHAR2(4000)
ROWS_LOADED NUMBER
LOGFILE_TABLE VARCHAR2(128)
BADFILE_TABLE VARCHAR2(128)
TEMPEXT_TABLE VARCHAR2(128)
SQL>
我们使用 USER_LOAD_OPERATIONS 视图返回当前会话的操作。
column type format a10
select id, type
from user_load_operations
order by 1;
ID TYPE
---------- ----------
1 COPY
11 COPY
SQL>
DELETE_OPERATION 过程允许我们清除与特定操作相关的附加文件。
begin
dbms_cloud.delete_operation(1);
end;
/
select id, type
from user_load_operations
order by 1;
ID TYPE
---------- ----------
11 COPY
SQL>
DELETE_ALL_OPERATIONS 过程允许我们清理所有操作的附加文件，或者如果我们指定类型值，则清理特定类型操作的附加文件。
-- Delete only COPY operations.
begin
dbms_cloud.delete_all_operations('COPY');
end;
/
-- Delete all operations.
begin
dbms_cloud.delete_all_operations;
end;
/
