Besides the SQL utility functions, Oracle inbuilt function library contains type conversion functions. There may be scenarios where the query character certificate for bank pdf input in a specific data type, but it receives it in a different data type. In such cases, Oracle implicitly tries to convert the unexpected value to a compatible data type which can be substituted in place and application continuity is not compromised. Type conversion can be either implicitly done by Oracle or explicitly done by the programmer.
Implicit data type conversion works based on a matrix which showcases the Oracle’s support for internal type casting. Besides these rules, Oracle offers type conversion functions which can be used in the queries for explicit conversion and formatting.
As a matter of fact, it is recommended to perform explicit conversion instead of relying on software intelligence. Though implicit conversion works well, but to eliminate the skew chances where bad inputs could be difficult to typecast internally. A VARCHAR2 or CHAR value can be implicitly converted to NUMBER or DATE type value by Oracle.
Note that the impicit interconversion happens only when the character represents the a valid number or date type value respectively. For example, examine the below SELECT queries. Both the queries will give the same result because Oracle internally treats 15000 and ‘15000’ as same.
SQL Conversion functions are single row functions which are capable of typecasting column value, literal or an expression . TO_CHAR, TO_NUMBER and TO_DATE are the three functions which perform cross modification of data types. For number to character conversion, nls parameters can be used to specify decimal characters, group separator, local currency model, or international currency model. It is an optional specification – if not available, session level nls settings will be used.