== Why is this an issue?

The ``++TO_NUMBER++`` function is converting the value of ``++BINARY_FLOAT++``, ``++BINARY_DOUBLE++``, ``++CHAR++``, ``++VARCHAR2++``, ``++NCHAR++``, or ``++NVARCHAR2++`` datatype to a value of ``++NUMBER++`` datatype.


Without providing the format of the input, ``++TO_NUMBER++`` will consider the provided value is compliant with the default format. Relying on a default configuration is a source of error because it creates a dependency between the code and the configuration of the ORACLE server where this code is deployed.

The behaviour of the ``++TO_NUMBER++`` function will certainly not be the expected one if the configuration of the ORACLE server is changing.


=== Noncompliant code example

The following code with return 0 on an ORACLE server running with its default US configuration with p_string = "2,540" 

[source,sql]
----
IF ( TO_NUMBER(p_string) >= 0 and TO_NUMBER(p_string) <= TO_NUMBER('50.00') ) THEN
  RETURN 1;
ELSE
  RETURN 0;
END IF;
----


=== Compliant solution

The following code with return 1 on an ORACLE server running with its default FR configuration with p_string = "2,540" because the comma will be interpreted as decimal separator instead of thousand separator.

[source,sql]
----
IF ( TO_NUMBER(p_string, '99.99') >= 0 and TO_NUMBER(p_string, '99.99') <= TO_NUMBER('50.00','99.99') ) THEN
  RETURN 1;
ELSE
  RETURN 0;
END IF;
----

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Provide the format of the input value.


endif::env-github,rspecator-view[]