Validating null value in oracle sql

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The ANSI SQL-92 specification states that a null must be the same for all data types, so that all nulls are handled consistently. CLR nullable types are not intended for storage of database nulls because an ANSI SQL null does not behave the same way as a in Visual Basic). For more information on working with CLR nullable types in Visual Basic see Nullable Value Types, and for C# see Using Nullable Types. The returns a Sql Boolean and can be used to check for null values. Sql Types provides the same semantics as when the ANSI_NULLS option is set on in SQL Server. Equals uses database semantics for evaluating nulls. Equals uses CLR type semantics for evaluating nulls. Equals shared/static method: Two nulls=Null String. NET Framework version 2.0 introduced support for nullable types, which allow programmers to extend a value type to represent all values of the underlying type.(like individual drop boxes ) that makes sure date is in expected format. for example November 12 2013" only in this cases you need separate function to validate Date. value the client retrieves that internal representation and converts it to a string based on its settings or your NLS_DATE_FORMAT, giving you something recognisable.

Dim a As New Sql String Dim b As New Sql String ' Compare nulls using static/shared Sql String. In Oracle XML DB, BEGIN -- Delete the schema, if it already exists; otherwise, this produces an error.DBMS_XMLSCHEMA.delete Schema(' END; / BEGIN -- Register the schema DBMS_XMLSCHEMA.register Schema(' '', TRUE, TRUE, FALSE); END; / -- Create table to hold XML instance documents DROP TABLE po_tab; CREATE TABLE po_tab (id NUMBER, xmlcol XMLType) XMLType COLUMN xmlcol XMLSCHEMA " ELEMENT "purchase Order"; INSERT INTO po_tab VALUES(1, XMLType( ' ipo:purchase Order: ship To: name: Helen Zoe street:100 Broadway city: Cardiff state: Wales country: UK zip: CF2 1QJ bill To: name: Robert Smith street:8 Oak Avenue city: Old Town state: CA country: US zip:95819 items: Often, besides knowing that a particular XML document is well-formed, it is necessary to know if a particular document conforms to a specific XML schema, that is, is VALID with respect to a specific XML schema.It would be a different matter if you were passing a string into a procedure and converting that to a date. You receive a date, which is either a valid date or NULL by definition.Then you would need to allow for and handle invalid inputs, unless you knew you could guarantee you were always going to be passed valid values - if it's only ever called from an application layer that did the validation, for example. No need to check anything (except for NULL, if you want so).

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