A data type is an attribute that specifies the type of data that the object can hold
Char Data type :This specify the character string and has a length specified by size.if you insert a shorter value the blank space will be counted and if you insert a longer value then it returns a error.Maximum length allowed is 2000 Bytes.
Varchar2 : this specify a variable length character string.maximum of 4000 bytes.
Numeric Data type : This number data type stores +ve & -ve numbers including zero.
Date :The date data type stores Date and time information.It can be represented in both character and number data type.
Time Stamp : This is extension of date data type it stores year,month,day,hour,minute, and second value it also stores fractional seconds.
Blob Data type : It stores unstructured binary data it can store upto 8terabytes of binary data.
Clob Data types : It stores character data it can store upto 8terabytes of character data
LITERALS : These are fixed data values similarly like constants.
Text Literals : Text,character and string these are always surrounded by single quotations mark.can have maximum length of 4000 bytes.
Numeric Literals : These are used to specify fixed and floating point number stores maximum of 38 digits of precision.
Date Literals : we can specify date as string literals or can convert char or num. value to date value.
Null Value : If a column in a table has no value then it is said to be Null. A column can have many null values unless its restricted by primary key or not null.in a column no value is equal to null or no two null values are same
Comments : comments are used to understand table clearly.this is optional.
begin with /* and end the statement with */.
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