Datatypes used in oracle database administration

Datatypes are the structural or the physical attributes of a table. I would say that the kind of table you create is determine by the data you are bringing into the table.  Datatypes helps determine the kind of data entered into a table. For example Column for phone numbers will not have the same kind of dataype with column for names.

Types of Datatypes

In oracle database, there a lot of datatypes used but I am going to filter it to the most commonly used in your day to day tasks as an administrator in creating your schema objects.

Here they are

1.            Varchar2 :- This allows the use of variables, character and numbers in a particular field/column.

               Variables such as *, @, #, _, -, >, %, ^, /, etc

               Characters such as alphabet A - Z

               Numbers such as 0 – 9

Examples of fields where you can use varchar2 are columns containing email address (chukwurahisaac@gmail.com), twitter handle @omegazee21. Etc

2.            Char:- This allows only the use of characters in a particular column.

               Character A –Z.

               You can use it in columns where you want only characters such as ‘names’ countries etc

3.            Date:- This is a datatype on its own. It stores point in time data values (data and time) in a table.

               Oracle can store dates in the Julian era from JAN 1, 4712BCE through Dec 31 4712CE/AD.

*Note    The default date format in oracle database is DD-MM-YYYY.

4.            Timestamp:- This stores date and time info with fractional precision for seconds. The only difference from date datatype is the ability to store time up to a precision of 9 digits.

5.            Number:- This type allows only numbers in the column used.

6.            Clob:-  CLOB is one of the Large Object datatypes provided to store variable-length character data. The maximum amount of data you can store in a CLOB column is based on the block size of the database. CLOB can store up to (4GB–1)*