What is difference between primary key and foreign key ?

  • Filter
  • Time
  • Show
Clear All
new posts

  • What is difference between primary key and foreign key ?

    Hello Friends,

    I have little bit confusion about this question what is main difference between primary key and foreign key /

    Please share with me...
    Modular Office Furniture Manufacturers | Modular Office Furniture Mumbai

  • #2
    every relation in the database should have the primary key so that the records can be distinguished.
    as we know the primary key has some characteristics:
    1> It cannot be null
    2.> It should be unique.
    Now the same key can be used in another table as the foreign key to making a relationship between two tables.
    there are certain constraints are applied as related to the update, insertion, and deletion of the records.
    sagittarius birthstone color | aries birthstone color | libra birthstone color | birthstones | Aries Birthstone Meaning


    • #3
      You cannot ignore Java considering how well the Android app market is performing


      • #4
        Difference between Primary Key and Foreign Key. Primary key uniquely identify a record in the table. Foreign key is a field in the table that is primary key in another table. By default, Primary key is clustered index and data in the database table is physically organized in the sequence of clustered index.


        • #5
          SQL Keys

          1. Primary Key

          The SQL Primary Key constraint is used to define the unique record in the table. It does not allow 'NULL' value. PK can be defined only once in the table.
          By default, creates a Clustered index and define once in the SQL table.

          2. Foreign Key

          The Foreign Key is the database concept to create the relation between tables. The purpose of the Foreign key is to define referential integrity of data between tables.
          A Foreign key prevents the physical creation of a record because until it doesn't fulfill relation. It's just a way to be safer.
          Enterprise Security Platform | protect sensitive data | prevent data loss


          • #6
            Primary key is always unique and never void. Whereas a foreign key is used to establish relationship between two tables. It helps in Database linking.
            MS Teams | MS Dynamics 365


            • #7
              Primary key is a special key which helps to uniquely identifies record in table. Primary key must be unique for each table just like serial number which cannot be same and unique for each row. One more thing primary key cannot contain null values.

              Foreign key is a field which helps to connect two tables together. It can be a column or group of column from which we can identify row from 2 or more tables.


              • #8
                Every table in database has a primary key and it is always unique can't be a Null whereas Foreign key is not unique and it is used to establish a relation in the tables
                sagittarius birthstone color | aries birthstone color | libra birthstone color | birthstones | Aries Birthstone Meaning


                • #9
                  A primary key is used to ensure data in the specific column is unique. A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables
                  Sumatriptan EP Impurity H | Sumatriptan EP Impurity A | Sumatriptan EP Impurity D | Sumatriptan EP Impurity E | Sumatriptan EP Impurity C


                  Unconfigured Ad Widget



                  1 of 2 < >

                  FreeHostForum Rules and Guidelines

                  Webmaster forum - Web Hosting Forum,Domain Name Forum, Web Design Forum, Travel Forum,World Forum, VPS Forum, Reseller Hosting Forum, Free Hosting Forum


                  Board-wide Policies:

                  Do not post links (ads) in posts or threads in non advertising forums.

                  Forum Rules
                  Posts are to be made in the relevant forum. Users are asked to read the forum descriptions before posting.

                  Members should post in a way that is respectful of other users. Flaming or abusing users in any way will not be tolerated and will lead to a warning or will be banned.

                  Members are asked to respect the copyright of other users, sites, media, etc.

                  Spam is not tolerated here in most circumstances. Users posting spam will be banned. The words and links will be censored.

                  The moderating, support and other teams reserve the right to edit or remove any post at any time. The determination of what is construed as indecent, vulgar, spam, etc. as noted in these points is up to Team Members and not users.

                  Any text links or images contain popups will be removed or changed.

                  Signatures may contain up to four lines

                  Text in signatures is subject to the same conditions as posts with respect decency, warez, emoticons, etc.

                  Font sizes above 3 are not allowed

                  Links are permitted in signatures. Such links may be made to non-Freehostforum material, commercial ventures, etc. Links are included within the text and image limits above. Links to offensive sites may be subject to removal.

                  You are allowed ONLY ONE picture(banner) upto 120 pixels in width and 60 pixels in height with a maximum 30kB filesize.

                  In combination with a banner/picture you can have ONLY ONE LINE text link.

                  Webmaster related advertising is allowed in Webmaster Marketplace section only. Free of charge.

                  Shopping related (tangible goods) advertising is allowed in Buy Sell Trade section only. Free of charge.

                  No advertising allowed except paid stickies in other sections.

                  Please make sure that your post is relevant.

                  More to come soon....
                  2 of 2 < >

                  Advertise at FreeHostForum

                  We offer competitive rates and a many kinds of advertising opportunities for both small and large scale campaigns.More and more webmasters find advertising at is a useful way to promote their sites and services. That is why we now have many long-term advertisers.

                  At here, we also want to thank you all for your support.

                  For more details:

                  More ad spots:
                  See more
                  See less