[SPARK-50792][SQL] Format binary data as a binary literal in JDBC.

[sunxiaoguang]

What changes were proposed in this pull request?

Format binary data as a binary literal in JDBC.

Why are the changes needed?

The binary data is not handled to format it as binary literal in JDBC connectors
These are the steps to reproduce.

1. CREATE TABLE test_binary_literal(b BINARY);
2. INSERT INTO test_binary_literal VALUES(x'010203');
3. SELECT * FROM test_binary_literal WHERE b=x'010203';

Does this PR introduce any user-facing change?

'No'

How was this patch tested?

Added new integration tests

Was this patch authored or co-authored using generative AI tooling?

'No'

[beliefer]

Please add the similar test case into JDBCV2Suite.

[beliefer]

Please prepare data at tablePreparation.

[sunxiaoguang]

tablePreparation

Sorry, I'm not quite familiar with the test infrastructure. In case I make mistakes, let me confirm this question.

To mixin the tablePreparation and dataPreparation from trait defined in V2JDBCTest.scala, we need to update all the integration tests and call the these functions defined in trait.

And duplicate the extra call to multiple integration tests is OK, am I right?

[sunxiaoguang]

Hm, Just realized I have to use Spark SQL to create table and use the types defined in Spark SQL. If I prepare table and data in tablePreparation and dataPreparation, that will have to be database specific. The code will definitely have to be duplicated for connectors of all the databases.

[beliefer]

Yes. If we update the basic class JdbcDialect, we should test all the built-in integration tests.
tablePreparation used to customize the DDL, I'm afraid Spark SQL can covers all the built-in integration tests. But you could do your best effort, let's see the result and make the decision.

[sunxiaoguang]

Wait, just realized each dialect embeds a builder which can override the implementation. Let me have a try.

[sunxiaoguang]

Oracle support is ready for review, PTAL. Thanks.

[beliefer]

You can override visitBinaryComparison in OracleSQLBuilder.

[sunxiaoguang]

There are couple threads discussing this topic. Let me copy the comment in case it's missed.

We can only rewrite comparison when one of the arguments is BLOB. For other cases, we have to use existing implementation. But unfortunately, the signature of visitBinaryComparison is accepting everything in string which loss the type information to understand if one of the arguments is binary type.

  protected String visitBinaryComparison(String name, String l, String r) {
    if (name.equals("<=>")) {
      return "((" + l + " IS NOT NULL AND " + r + " IS NOT NULL AND " + l + " = " + r + ") " +
              "OR (" + l + " IS NULL AND " + r + " IS NULL))";
    }
    return l + " " + name + " " + r;
  }

[sunxiaoguang]

All tests passed, but downloading report failed. We can rerun the whole test again to clear all the checks, but it takes quite some time to finish.
https://github.com/sunxiaoguang/spark/actions/runs/12744731853

[beliefer]

The test case skips the Oracle, but the users still possible use this case.

[sunxiaoguang]

Yes, that requires a significant change in how V2ExpressionSQLBuilder works. The binary literal was not working before this PR anyway. We can make it work at least on other databases this time. And propose another design changes to V2ExpressionSQLBuilder to make it flexible enable to support cases like this.

[sunxiaoguang]

As Oracle is supported, the test is now enabled for Oracle.

[beliefer]

That's not a good idea if the bug still exists when using oracle dialect. Is there a way to fix the bug?

[beliefer]

Yes, that requires a significant change in how V2ExpressionSQLBuilder works. The binary literal was not working before this PR anyway. We can make it work at least on other databases this time. And propose another design changes to V2ExpressionSQLBuilder to make it flexible enable to support cases like this.

Why we need change V2ExpressionSQLBuilder? Please describe the detail.

[sunxiaoguang]

Sorry for the confusion; I didn't check the inheritance structure initially. After realizing that each dialect embeds a builder inherited from V2ExpressionSQLBuilder, I made all the changes in OracleDialect. PTAL

[sunxiaoguang]

BTW: I just changed test to verify the returned result in addition. It's going to run for a while.

[sunxiaoguang]

All tests passed, but downloading report failed. We can rerun the whole test again to clear all the checks, but it takes quite some time to finish.
https://github.com/sunxiaoguang/spark/actions/runs/12744731853

[beliefer]

You just need override visitBinaryComparison

[sunxiaoguang]

We can only rewrite comparison when one of the arguments is BLOB. For other cases, we have to use existing implementation. But unfortunately, the signature of visitBinaryComparison is accepting everything in string which loss the type information to understand if one of the arguments is binary type.

  protected String visitBinaryComparison(String name, String l, String r) {
    if (name.equals("<=>")) {
      return "((" + l + " IS NOT NULL AND " + r + " IS NOT NULL AND " + l + " = " + r + ") " +
              "OR (" + l + " IS NULL AND " + r + " IS NULL))";
    }
    return l + " " + name + " " + r;
  }

[sunxiaoguang]

All tests passed, but downloading report failed. We can rerun the whole test again to clear all the checks, but it takes quite some time to finish.
https://github.com/sunxiaoguang/spark/actions/runs/12744731853