Process to Create Table in SQL

For Creating a New Table: For creating a new table in the SQL Server, you need to follow the following process:

• Type the command i.e. enter the keyword “create table”
• Type the table name
• Insert open parenthesis
• Type first column name
• Enter the data type for that column
• Enter any optional constraints
• Insert closing parenthesis

Points to Remember: It is important to remember the following points while performing the process of creating a table in SQL:

• Use open parenthesis before starting the table
• Use a closing parenthesis at the end of the last column definition of the table
• Separate each column definition using a comma
• SQL statements must end with “;”

Make sure that table name and column names start with a letter. They can be followed by letters, numbers, or underscores (limit is 30 characters in length). Always remember that you should not use any SQL reserved keywords as table names or column names (like you must not use keywords like select, create, insert, etc).

Most Common Data types: Following are the most common data types using in SQL:

• char(size): It is the fixed length of the string of characters of the set size. The string size is limited to 255 characters
• date
• number(maxsize): It is the number with a maximum digits specified by “maxsize”
• number(maxdigits, maxright): It is a decimal number with minimum “maxdigits” and with maximum digits to the right of the decimal, “maxright”
• varchar(maxsize): It is a character string with variable length limited to
  “maxsize”

Constraints: Constraints are basically the rules for the column. Below mentioned are the possible values:

• Not null: This means that the column values must have some value and they cannot be null
• Primary key: This means that each record is distinctively identified by this column
• Unique key: This means that two values may not be same in the column