A Nchar Data Type is a character data type in SQL that is used to store fixed-length Unicode character strings. It is commonly found in database systems such as Oracle, Microsoft SQL Server, and MySQL.
Unicode is a universal character encoding standard that supports characters from almost all writing systems across the world. It ensures that data can be stored and retrieved accurately irrespective of different languages or scripts.
The Nchar data type differs from the Varchar data type, which is used to store variable-length character strings. While Varchar can store strings of varying lengths, Nchar can only store strings of a fixed length.
When defining an Nchar column, you need to specify the maximum number of characters it can hold. For example, if you define an Nchar(10) column, it will always occupy 10 characters of storage space regardless of the actual length of the stored string.
Nchar columns are useful in scenarios where you need to ensure consistent storage space for each record, such as when storing names, addresses, or any other fixed-length textual information.
Here’s an example of creating an Nchar column in Oracle:
Create Table:
CREATE TABLE Employees (
EmployeeID NUMBER,
EmployeeName NCHAR(50),
..
);
In this example, we create an “Employees” table with an “EmployeeName” column defined as Nchar(50). This means that the “EmployeeName” column will always occupy 50 characters’ worth of storage space for each record.
One important thing to note is that since Nchar stores Unicode characters, it requires more storage space compared to non-Unicode character types like Char or Varchar.
When retrieving data from an Nchar column, any trailing spaces are preserved. For example, if you store the name “John” in an Nchar(10) column, retrieving it will return “John ” (with spaces to fill up the remaining characters).
Here’s an example of inserting data into an Nchar column in SQL Server:
Insert Data:
INSERT INTO Employees (EmployeeID, EmployeeName)
VALUES (1, N'John');
In this example, we insert a record with an EmployeeID of 1 and an EmployeeName of ‘John’ into the Employees table. The ‘N’ prefix before the string indicates that it is a Unicode string.
In conclusion, the Nchar data type is a fixed-length Unicode character data type used in SQL databases. It ensures consistent storage space for each record but requires more storage compared to non-Unicode character types. It is useful when dealing with textual information that has a fixed length requirement.