如何使用 JDBC 的 Oracle DBMS 的 COPY 表命令？

Question

I'm trying copy table from one database to another(On different machines), and using JDBC Template to execute query, but this request is specific to Oracle:

COPY FROM username1/passwd1@//192.168.3.17:1521/PROD_SERVICE to username2/passwd2@//192.168.4.17:1521/SANDBOX_SERVICE INSERT TABLE_C (*) USING (SELECT * FROM TABLE_C);

And I get error:

Caused by: java.sql.SQLSyntaxErrorException: ORA-00900: invalid SQL statement

How can I use specific to Oracle syntax in JDBC?

Answer 1

Like some of the comments have already clarified, COPY is a sqlplus command, and it has been deprecated for a while. You cannot use it inside JAVA, because this command is not part of the SQL engine, it's just a kind of additional feature available only in sqlplus. It is still available, but only for backwards compatibility.

If you want to copy a table using Java, you need to understand first some things:

• Java, or any external engine for that matter, can't connect at the same time to both databases. Either it connects to one or to the other.
• You need to have a kind of bridge between both databases, so that your Java program is only acting as trigger.
• Copying tables between databases is something related to the database, so you should think in using tools provided by your database engine. You have some options, like Datapump or RMAN, although I consider Datapump the best suitable for your scenario.

However, if you insist in using Java, first you need to have a database link between both databases. Then you can use Java to invoke an insert from one database to another.

https://docs.oracle.com/database/121/SQLRF/statements_5006.htm#SQLRF01205

If you don't want to depend on thsnames entries in the server, here an example of database links:

CREATE DATABASE LINK to_my_remote_user 
   CONNECT TO remote_user IDENTIFIED BY password
   USING '(DESCRIPTION=
            (ADDRESS=(PROTOCOL=TCP)(HOST=remote_server)(PORT=remote_port))
            (CONNECT_DATA=(SERVICE_NAME=remote_service_name))
          )';

Once you have the dblink created, then you can connect from java to the database where the link is available and copy the data to the remote database

INSERT INTO remote_user.remote_table@to_my_remote_user 
select * from local_user.local_table ;

Important : Normally dblinks are not allowed on Production systems, because they increase security risks. Also remember that DDL operations over a database link require an extra step, such as using the procedure DBMS_UTILITY.EXEC_DDL_STATEMENT@dblink('create table...);

Another option outside of Java is using SQL Developer copy feature. Although I only recommend it for small tables. If you want to use it with big tables, it will probably hang. You can read here an good example:

copy from one database to another using oracle sql developer - connection failed