![]() ![]() The clause NO DELETE UNTIL 16 DAYS AFTER INSERT protects rows for the specified number of days.The row retention clause determines how long each row will be protected from the NO DELETE This clause alone means that the rows are kept forever.On the other hand, NO DROP UNTIL 31 DAYS IDLE means that the table can't be dropped until no rows have been inserted for that number of days. NO DROP by itself means that the table can never be dropped. The table will still be dropped if a DROP USER CASCADE command is issued to drop the entire schema. The DROP TABLE clause determines how long the table is protected from deletion.There are three clauses to be aware of in the blockchain table: ![]() The table creation looks like a regular table except that you need to add the BLOCKCHAIN keyword to the table creation command. ![]() You can also disable row deletions altogether or allow rows to be deleted beyond a time threshold. You can add rows at the end of the table, but you can't update those rows. Therefore, the hash can verify that a row has not been tampered with because as soon as the data changes, the hash will calculate a different value. The hash is stored in the row's metadata. The hash is based on the data in the current row plus the hash value of the previous row in the chain. A blockchain table in Oracle 21c is a tamper-proof insert-only table with an associated table level and row-level retention period.īriefly, a blockchain table works as follows: Each row except the first row is chained to the previous row in the chain using a cryptographic hash (SHA2-512). Blockchain is a shared and immutable ledger that facilitates the process of recording transactions and tracking assets in a business network. ![]() Oracle 21c database introduced new Blockchain tables. This overview walks through the basics of each of these supported features and offers some select use cases. Quest© Toad© for Oracle 15.1 supports a variety of Oracle 21c new features. ![]()
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