if (isKeyword(constantName)) {
throw DbException.get(ErrorCode.CONSTANT_ALREADY_EXISTS_1, constantName);
}
read("VALUE");
Expression expr = readExpression();
CreateConstant command = new CreateConstant(session, schema);
command.setConstantName(constantName);
command.setExpression(expr);
command.setIfNotExists(ifNotExists);
return command;
}