What Are Oracle Blockchain Tables? (And What’s New in Oracle 23ai)

Keywords: Oracle Blockchain Table, Oracle 23ai, immutable data, blockchain in database, Oracle new features

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Introduction

If you’re in IT, data security, or compliance, you’ve probably heard the word “blockchain” thrown around a lot. But what if I told you Oracle lets you use blockchain-style features directly in your database? No, not some complex integration with cryptocurrency platforms—but right there in Oracle Database.

Welcome to Oracle Blockchain Tables—a feature that’s been around since Oracle 21c and just got a major upgrade in Oracle 23ai.

In this blog, I’ll walk you through what Oracle Blockchain Tables are, why they matter, and what’s new in the Oracle 23ai release.

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What is an Oracle Blockchain Table?

At its core, a Blockchain Table is a special kind of table that ensures data cannot be changed once it’s inserted. It’s like writing data in permanent ink.

Here’s what makes it different from a regular table:

• ✅ Insert-only: You can only insert data. No updates, no deletes.
• 🔐 Tamper-proof: Every row is connected using cryptographic hashes—just like in blockchain technology.
• 🕒 Retention rules: You can set how long rows must be kept and when they can be dropped.
• 📄 Audit-ready: Perfect for financial records, compliance logs, supply chains, and anything you never want tampered with.

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Why Use Blockchain Tables?

Imagine you’re storing financial transactions, employee access logs, or medical records. You want those entries to be unalterable and fully traceable.

With blockchain tables:

• You prevent fraud by making the data tamper-proof.
• You meet compliance requirements easily.
• You create a verifiable audit trail inside your existing Oracle environment.

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What’s New in Oracle 23ai for Blockchain Tables?

Oracle 23ai introduces powerful upgrades to make blockchain tables more flexible and easier to use. Here are the key features:

1. 🔁 GoldenGate Support

Now you can replicate blockchain tables using Oracle GoldenGate, keeping data synchronized across databases without breaking immutability.

2. 🚀 Faster Inserts & Commits

Insert and commit operations are faster and more efficient, making it easier to use blockchain tables in high-volume apps.

3. 🔧 Schema Flexibility (Add/Drop Columns)

Need to tweak your schema? Oracle 23ai lets you add or drop columns in blockchain tables without breaking the hash chain. That’s huge!

4. 🔐 Delegate Signing & Database Signing

Users can now sign records on behalf of others, and Oracle itself can also counter-sign rows for added trust.

5. 🔍 Track Changes in Regular Tables

Want blockchain-style audit for normal tables? Use Flashback Archive with a blockchain history table. Now every change is cryptographically secure.

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Real Example with SQL Commands

Here’s a quick walkthrough using real Oracle SQL commands:

-- Connect to your database
ALTER SESSION SET CONTAINER = freepdb1;
CONN hol23c/oracle;

-- Create a Blockchain Table
CREATE BLOCKCHAIN TABLE bct_t1 (
  id            NUMBER,
  fruit         VARCHAR2(20),
  quantity      NUMBER,
  created_date  DATE,
  CONSTRAINT bct_t1_pk PRIMARY KEY (id)
)
NO DROP UNTIL 0 DAYS IDLE
NO DELETE UNTIL 16 DAYS AFTER INSERT
HASHING USING "SHA2_512" VERSION "v2";

-- Insert data
INSERT INTO bct_t1 (id, fruit, quantity, created_date)
VALUES (1, 'Apple', 100, SYSDATE);

COMMIT;

-- Try updating (it will fail!)
UPDATE bct_t1 SET quantity = 50 WHERE id = 1;
-- ERROR: Can't update in a blockchain table!

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Can I Drop or Modify These Tables?

Sort of—but with strict rules.

You can set retention policies like:

ALTER TABLE bct_t1 NO DELETE UNTIL 32 DAYS AFTER INSERT;

You can increase the days but not reduce them. That’s by design—to protect the data.

Adding a Column

ALTER TABLE bct_t1 ADD (transaction_type VARCHAR2(20));

Signing a Row

DECLARE
  l_signature BLOB;
BEGIN
  -- Retrieve row data and generate signature
  -- Sign the row using DBMS_BLOCKCHAIN_TABLE.SIGN_ROW
END;

Verifying Rows

DECLARE
  l_verified NUMBER;
BEGIN
  DBMS_BLOCKCHAIN_TABLE.VERIFY_ROWS(
    schema_name => 'user',
    table_name  => 'transactions',
    number_of_rows_verified => l_verified
  );
  DBMS_OUTPUT.PUT_LINE('Verified Rows: ' || l_verified);
END;

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Use Cases for Oracle Blockchain Tables

Oracle Blockchain Tables are particularly useful in scenarios where data integrity and auditability are critical:

• Financial Ledgers: Maintaining a secure and immutable record of financial transactions.
• Supply Chain Tracking: Ensuring the authenticity and traceability of goods and materials.
• Regulatory Compliance: Providing verifiable audit trails for compliance with industry regulations.
• Legal Documentation: Creating tamper-proof records of legal agreements and documents.​

Final Thoughts

Oracle Blockchain Tables bring the security of blockchain into the familiar world of relational databases. With Oracle 23ai, they’ve become even more powerful, efficient, and flexible.

So if your application needs trustworthy, tamper-proof data, you don’t have to look to external blockchain platforms. It’s all built into Oracle now.