How to use

supportsCharSet

method

in

org.apache.calcite.sql.SqlDialect

public SqlNode getCastSpec(RelDataType type) {
 if (type instanceof BasicSqlType) {
  return new SqlDataTypeSpec(
    new SqlIdentifier(type.getSqlTypeName().name(), SqlParserPos.ZERO),
      type.getPrecision(),
      type.getScale(),
      type.getCharset() != null
        && supportsCharSet()
        ? type.getCharset().name()
        : null,
      null,
      SqlParserPos.ZERO);
 }
 return SqlTypeUtil.convertTypeToSpec(type);
}

public SqlNode getCastSpec(RelDataType type) {
 if (type instanceof BasicSqlType) {
  int precision = type.getPrecision();
  switch (type.getSqlTypeName()) {
  case VARCHAR:
   // if needed, adjust varchar length to max length supported by the system
   int maxPrecision = getTypeSystem().getMaxPrecision(type.getSqlTypeName());
   if (type.getPrecision() > maxPrecision) {
    precision = maxPrecision;
   }
  }
  return new SqlDataTypeSpec(
    new SqlIdentifier(type.getSqlTypeName().name(), SqlParserPos.ZERO),
      precision,
      type.getScale(),
      type.getCharset() != null
        && supportsCharSet()
        ? type.getCharset().name()
        : null,
      null,
      SqlParserPos.ZERO);
 }
 return SqlTypeUtil.convertTypeToSpec(type);
}

private SqlNode toSql(RelDataType type) {
 switch (dialect.getDatabaseProduct()) {
  case MYSQL:
   switch (type.getSqlTypeName()) {
    case VARCHAR:
     // MySQL doesn't have a VARCHAR type, only CHAR.
     return new SqlDataTypeSpec(new SqlIdentifier("CHAR", POS),
       type.getPrecision(), -1, null, null, POS);
    case INTEGER:
     return new SqlDataTypeSpec(new SqlIdentifier("_UNSIGNED", POS),
       type.getPrecision(), -1, null, null, POS);
   }
   break;
 }
 if (type instanceof BasicSqlType) {
  return new SqlDataTypeSpec(
    new SqlIdentifier(type.getSqlTypeName().name(), POS),
    type.getPrecision(),
    type.getScale(),
    type.getCharset() != null
      && dialect.supportsCharSet()
      ? type.getCharset().name()
      : null,
    null,
    POS);
 }
 return SqlTypeUtil.convertTypeToSpec(type);
 //throw new AssertionError(type); // TODO: implement
}