@Override
  public Statement visitShowDatabases(IoTDBSqlParser.ShowDatabasesContext ctx) {
    ShowDatabaseStatement showDatabaseStatement;

    // Parse prefixPath
    if (ctx.prefixPath() != null) {
      showDatabaseStatement = new ShowDatabaseStatement(parsePrefixPath(ctx.prefixPath()));
    } else {
      showDatabaseStatement =
          new ShowDatabaseStatement(new PartialPath(SqlConstant.getSingleRootArray()));
    }

    // Is detailed
    showDatabaseStatement.setDetailed(ctx.DETAILS() != null);

    return showDatabaseStatement;
  }
Check and set datatype, encoding, compressor.

@throws SemanticException if encoding or dataType meets error handling
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/parser/ASTVisitor.java