What is the difference between type and subtype in oracle

When the bind value is Line No. This environment variable opens up an output buffer of size limit of Start of the declare section of the block. Start of the execution section of the block. End of the execution section of the block. In the below example, a NOT NULL constraint is imposed on the number data type to make sure no null values are assigned to the variable.

When the bind value is 5. Both fixed-width and variable-width character sets are supported. Every CLOB variable stores a locator, which points to a large block of character data. CLOB s participate fully in transactions, are recoverable, and can be replicated. CLOB locators can span transactions for reads only , but they cannot span sessions. NCLOB s participate fully in transactions, are recoverable, and can be replicated.

NCLOB locators can span transactions for reads only , but they cannot span sessions. After defining a subtype, you can declare items of that type. The subtype name indicates the intended use of the variable.

You can constrain a user-defined subtype when declaring variables of that type, as in Example Subtypes can increase reliability by detecting out-of-range values. Example restricts the subtype pinteger to storing integers in the range An unconstrained subtype is interchangeable with its base type.

Example assigns the value of amount to total without conversion. Different subtypes are also interchangeable if their base types are in the same data type family. For example, the value of verb can be assigned to sentence :. Sometimes it is necessary to convert a value from one data type to another.

For example, to use a DATE value in a report, you must convert it to a character string. For best reliability and maintainability, use explicit conversion. Implicit conversion is context-sensitive and not always predictable, and its rules might change in later software releases. Implicit conversion can also be slower than explicit conversion. To explicitly convert values from one data type to another, you use built-in functions, which are described in Oracle Database SQL Language Reference.

This is called implicit conversion, and the data types are called compatible. When two data types are compatible, you can use a value of one type where a value of the other type is expected. For example, you can pass a numeric literal to a subprogram that expects a string value, and the subprogram receives the string representation of the number.

In such cases, you must use explicit conversion. Conversion rules for the DATE data type also apply to the datetime data types. However, because of their different internal representations, these types cannot always be converted to each other. Each character represents the hexadecimal equivalent of a nibble half a byte. Composite Data items that have internal components that can be accessed individually.

Explained in "Cursor Variables". Large Object LOB Pointers to large objects that are stored separately from other data items, such as text, graphic images, video clips, and sound waveforms. Subtypes A subtype is a subset of another data type, which is its base type. Character Alphanumeric values that represent single characters or strings of characters, which you can manipulate. Datetime Dates and times, which you can manipulate. Interval Time intervals, which you can manipulate. See Also: "Subprograms that You Can Overload" , for information about writing libraries that accept different numeric types.

Otherwise: Any value that is too small is rounded to zero. A literal value that is too large causes a compilation error. Comparing Character Values You can use relational operators in Table to compare character values. Avoiding Truncation Problems with Date and Time Subtypes The default precisions for some date and time types are less than the maximum precision. Cannot exceed 4 gigabytes GB. Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. What is the difference between "type" and "subtype" keywords? Ask Question. ANSI specific floating-point type with maximum precision of binary digits approximately 38 decimal digits. ANSI and IBM specific floating-point type with maximum precision of binary digits approximately 38 decimal digits.

The DATE datatype is used to store fixed-length datetimes, which include the time of day in seconds since midnight. For example, the default might be 'DD-MON-YY', which includes a two-digit number for the day of the month, an abbreviation of the month name, and the last two digits of the year.

For example, OCT Each DATE includes the century, year, month, day, hour, minute, and second.