D.3 Using Oracle Data Pump to Migrate to JSON Data Type

With this migration approach you use Oracle Data Pump, in data-only mode, to load the data from the original table that has a textual JSON column into a new table of the same shape, but with a JSON-type column.

Follow these steps:

1. Create the new table, j_purchaseorder_new, using code similar to that of Example 4-1, that is, with the same shape as the original table, j_purchaseorder, but with a JSON-type column instead of the textual JSON column.

   
   CREATE TABLE j_purchaseorder_new (id VARCHAR2(32),
                                     date_loaded TIMESTAMP(6) WITH TIME ZONE,
                                     data        JSON);

2. Use command-line client expdp, to export the data from the original table, j_purchaseorder, to a dump file, purchase_ord_txt.dmp. (table_owner, here, is the database schema that owns the table, and password is its password.)

   expdp table_owner/password tables=j_purchaseorder directory=mydir dumpfile=purchase_ord_txt.dmp logfile=expdp_po.log

3. Use command-line client impdp, to import the dumped data into the new table, using data-only mode.

   In this example, table_owner, is a placeholder for the database schema that owns the table; password is a placeholder for its password; and dumpfile_dir is a placeholder for the directory that contains the dump file.

   impdp table_owner/password tables=j_purchaseorder directory=dumpfile_dir dumpfile=purchase_ord_txt.dmp logfile=impdp_po.log
   remap_table=j_purchaseorder:j_purchaseorder_new content=data_only

4. Drop the original table, or rename it to some third name, and then rename the new table to the original table name. This is shown in Example D-4.

See Also:

Oracle Data Pump