OpenAPITools/openapi-generator · error · RuntimeException

Empty database/table/column name for property '{name}' not a

Error message

Empty database/table/column name for property '{name}' not allowed

What it means

The Ktorm schema generator derives database/table/column names from OpenAPI identifiers and sanitizes them (stripping illegal characters, trailing whitespace, etc.). If sanitization reduces a name to the empty string, escapeDatabaseName throws 'Empty database/table/column name for property ... not allowed' (KtormSchemaCodegen.java:1079) because an identifier-less column cannot be emitted. Earlier conditions (trailing spaces, all-digit names) are only warned about and repaired; emptiness is fatal.

Source

Thrown at modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KtormSchemaCodegen.java:1079

     * @return identifier name
     */
    public String toIdentifier(String name, String prefix, String suffix) {
        String escapedName = escapeQuotedIdentifier(name);
        // Database, table, and column names cannot end with space characters.
        if (escapedName.matches(".*\\s$")) {
            LOGGER.warn("Database, table, and column names cannot end with space characters. Check '{}' name", name);
            escapedName = escapedName.replaceAll("\\s+$", "");
        }

        // Identifiers may begin with a digit but unless quoted may not consist solely of digits.
        if (escapedName.matches("^\\d+$")) {
            LOGGER.warn("Database, table, and column names cannot consist solely of digits. Check '{}' name", name);
            escapedName = prefix + escapedName + suffix;
        }

        // identifier name cannot be empty
        if (escapedName.isEmpty()) {
            throw new RuntimeException("Empty database/table/column name for property '" + name + "' not allowed");
        }
        return escapedName;
    }

    /**
     * Escapes identifier to use it in SQL statements with backticks, eg. SELECT "identifier" FROM
     * Ref: https://www.sqlite.org/draft/tokenreq.html H41130
     * Spec is similar to MySQL
     *
     * @param identifier source identifier
     * @return escaped identifier
     */
    public String escapeQuotedIdentifier(String identifier) {
        // ASCII: [0-9,a-z,A-Z$_] (basic Latin letters, digits 0-9, dollar, underscore) Extended: U+0080 .. U+FFFF
        // ASCII NUL (U+0000) and supplementary characters (U+10000 and higher) are not permitted in quoted or unquoted identifiers.
        // This does in fact matches against >\xFFFF and against ^\x0000. works only on Java7+
        Pattern regexp = Pattern.compile("[^0-9a-zA-z$_\\x0080-\\xFFFF]");
        Matcher matcher = regexp.matcher(identifier);

View on GitHub (pinned to fcec517be3)

Solutions

1. Rename the offending property (the message includes the property name) to start with a letter or underscore and contain word characters.
2. Lint the spec for identifiers that contain no [A-Za-z0-9_] characters before generation.
3. If the symbolic name is mandated upstream, map it via a saner property name plus `x-` vendor extension or spec preprocessing.

Example fix

# before (api.yaml)
components:
  schemas:
    Row:
      properties:
        "###": { type: string }
# after
components:
  schemas:
    Row:
      properties:
        hash_prefix: { type: string }

// reject identifiers that sanitize to nothing before generation
Pattern wordChars = Pattern.compile("[^\\w]");
void checkIdentifiers(Map<String, Schema> props, String schemaName) {
  for (String key : props.keySet()) {
    if (wordChars.matcher(key).replaceAll("").isEmpty()) {
      throw new IllegalArgumentException(
          "Property '" + key + "' in '" + schemaName + "' has no valid identifier characters");
    }
  }
}

try {
    new DefaultGenerator().opts(clientOptInput).generate();
} catch (RuntimeException e) {
    // message contains the offending property name; rename it in the spec and retry
    throw new BuildException("Ktorm schema generation failed: " + e.getMessage(), e);
}

When it happens

Trigger: A schema property, model, or vendor-extension table/column name whose characters are all stripped during escaping — e.g. a property named `###`, `$`, `***`, or one made solely of whitespace/punctuation — reaching escapeDatabaseName() during ktorm schema generation.

Common situations: Hand-edited specs with placeholder names; specs generated from external systems where a field's display name is pure symbols; rename scripts that mangle property keys; properties whose name consists only of characters illegal in SQL identifiers.

Related errors

• Empty database/table/column name for property '{name}' not a
• Empty database/table/column name for property '{name}' not a
• The BLOB and JSON data types cannot be assigned a default va
• The BLOB, TEXT, GEOMETRY, and JSON data types cannot be assi
• The BLOB, TEXT, GEOMETRY, and JSON data types cannot be assi

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/44722cbb948f0830. Report an issue: GitHub.