Problem

StarRocksCatalog.buildColumnStmt() wraps all default values with double quotes unconditionally:

This generates invalid DDL for SQL keywords like CURRENT_TIMESTAMP:

-- Generated (incorrect):
`created_at` DATETIME NOT NULL DEFAULT "CURRENT_TIMESTAMP"

-- Expected:
`created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP

StarRocks rejects this with:
Getting analyzing error. Detail message: Invalid default value for 'created_at': date literal [CURRENT_TIMESTAMP] is invalid.

How to reproduce

1. Create a PostgreSQL table with DEFAULT CURRENT_TIMESTAMP
2. Set up a Flink CDC (>= 3.2.0) pipeline with StarRocks sink
3. Pipeline fails on StarRocksCatalog.createTable() with the error above

Suggested fix

Distinguish between literal values (need quotes) and SQL keywords/functions (must not be quoted):

if (column.getDefaultValue().isPresent()) {
    String defaultValue = column.getDefaultValue().get();
    if (isKeywordDefault(defaultValue)) {
        builder.append(String.format(" DEFAULT %s", defaultValue));
    } else {
        builder.append(String.format(" DEFAULT \"%s\"", defaultValue));
    }
}

Where isKeywordDefault() checks for known expressions such as CURRENT_TIMESTAMP.

Environment

• starrocks-connector-for-apache-flink: 1.2.10_flink-1.19
• Flink CDC: 3.5.0
• StarRocks: 4.0.6
• Source: PostgreSQL (DEFAULT CURRENT_TIMESTAMP)

References

• StarRocks CREATE TABLE docs — DEFAULT current_timestamp is supported (without quotes)
• FLINK-34638 — Flink CDC 3.2.0, default value propagation added
• FLINK-38248 — Flink CDC 3.5.0, 0000-00-00 00:00:00 default value fix (similar issue, different case)