Client Globalization Settings

Client globalization settings are derived from the Oracle globalization setting (NLS_LANG) in the Windows registry of the local computer. The client globalization parameter settings are read-only and remain constant throughout the lifetime of the application. The client globalization settings can be obtained by calling the OracleGlobalization.GetClientInfo() static method.

The following example retrieves the client globalization setting:

// C#
...
// GetClientInfo() is a static method on OracleGlobalization class
OracleGlobalization ClientGlob = OracleGlobalization.GetClientInfo();

The properties of the OracleGlobalization object provide the Oracle globalization value settings.

Session Globalization Settings

Session globalization parameters are initially identical to client globalization settings. Unlike client settings, session globalization settings can be updated. However, they can only be obtained after establishing a connection against the database server. The session globalization settings can be obtained by calling GetSessionInfo() on the OracleConnection. Invoking this method returns an instance of an OracleGlobalization object whose properties represent the globalization settings of the session.

When the OracleConnection object establishes a connection, it implicitly opens a session whose globalization parameters are initialized with those values specified by the client computer's Oracle globalization (or National Language Setting (NLS)) registry settings. The session settings are updatable and can change during its lifetime.

The following example changes the date format setting on the session:

// C#
...
OracleConnection con = new OracleConnection("User Id=scott;Password=tiger;");
con.Open();
OracleGlobalization SessionGlob = con.GetSessionInfo();

// SetSessionInfo updates the Session with the new value
SessionGlob.DateFormat = "YYYY/MM/DD"; 
con.SetSessionInfo(SessionGlob);       
...

Thread-Based Globalization Settings

Thread-based globalization parameter settings are specific to each thread. Initially, these settings are identical to the client globalization parameters, but they can be changed as specified by the application. When ODP.NET Types are converted to and from strings, the thread-based globalization parameters are used, if applicable.

Thread-based globalization parameter settings are obtained by invoking the GetThreadInfo static method of the OracleGlobalization object. The SetThreadInfo static method of the OracleGlobalization object can be called to set the thread's globalization settings.

ODP.NET classes and structures rely solely on the OracleGlobalization settings when manipulating culture-sensitive data. They do not use .NET thread culture information. If the application uses only .NET types, OracleGlobalization settings have no effect. However, when conversions are made between ODP.NET types and .NET types, OracleGlobalization settings are used where applicable.

The following code snippet shows how the thread's globalization settings are used by the ODP.NET Types:

...
OracleGlobalization ThreadGlob = OracleGlobalization.GetThreadInfo();
// set and validate the format
ThreadGlob.DateFormat = "YYYY-MM-DD";

// set the thread with the new format
OracleGlobalization.SetThreadInfo(ThreadGlob); 

// create a new instance of OracleDate
OracleDate date = new OracleDate("2002-01-01"); 
...

The OracleGlobalization object validates property changes made to it. If an invalid value is used to set a property, an exception is thrown. Note that changes made to the Territory and Language properties change other properties of the OracleGlobalization object implicitly.

Operations Dependent on Client Computer's Globalization Settings

The OracleString structure depends on the client computer's OracleGlobalization settings. The local computer's client character set is used when it converts a Unicode string to a byte[] in the GetNonUnicode method and when it converts a byte[] of ANSI characters to Unicode in the OracleString constructor which accepts a byte[].

Operations Dependent on Thread Globalization Settings

The thread globalization settings are used by ODP.NET types whenever they are converted to and from .NET string types, where applicable. In most cases, the ToString method, the Parse static method, constructors that accept .NET string data, and conversion operators to and from .NET strings use specific thread globalization settings depending on the ODP.NET type used.

For example, the OracleDate type uses the DateFormat property of the thread globalization settings when the ToString method is invoked on it. This returns a DATE as a string in the format specified by the thread's settings.

For more details, read the remarks in Chapter 5 for the ODP.NET type methods that convert between ODP.NET types and .NET string types, to identify which thread globalization settings are used for that particular method.

Operations Sensitive to Session Globalization Parameters

Session globalization settings affect any data that is retrieved from or sent to the server as a string.

For example, if a DATE column is selected with the TO_CHAR() function applied on it, the DATE column data will be a string in the date format specified by the DateFormat of the session globalization settings. Transmitting data in the other direction, the string data that is to be inserted into the DATE column, must be in the format specified by the DateFormat property of the session globalization settings.

The session globalization settings also affect data that is retrieved into the DataSet as a string using Safe Type Mapping. If the type is format-sensitive, the strings are always in the format specified by the session globalization settings.

For example, VARCHAR2 and CHAR data are not affected by session settings since no format is applicable for these types. However, the DateFormat and NumericCharacters properties can impact the string representation of DATE and NUMBER types, respectively, when they are retrieved as strings from the database server through safe type mapping.