DBMS Indexing: The Basic Concept

A quick introduction to the concept of indexing in RDBMSs

[JollyAZ]

Indexes are used to quickly locate data without having to search every row in a database table every
time a database table is accessed. An index is a copy of selected columns of data from a table, called a database key that can be searched very efficiently that also includes a low-level disk block address or direct link to the complete row of data it was copied from.

[Vikasslytherine]

The analogy helped me a lot to understand and now I don't think I will forget this concept. Thanks a lot!

[innate-videos]

Thank you Brian, great intro and great description. Very helpful!

[ShabnamKhan-cjzc]

Wow that was awsome....explained with such a simple example..thanks a lot

[ananyaimtiazhussain]

nice video. tomorrow is my exam on web designing, circuit, history of computer technology, programming and database. I didn't know anything about database management. the video really helped.
thanks

[erichansen]

I use many Flat Files, with fixed-length records, and "text" fields, working in tandem with Perl SDBM binary files of key/value pairs tied to Perl program hash tables. These key/value pairs offer persistent, instantaneous, random access to Flat File records. For random access, the file pointer is first set to a single record location byte offset, where the offset is the number of bytes to seek to from either TOP of file or END of file. Then the record is read into memory. Once in memory, the contents of the record can be changed/modified and written back out to the Flat File, overwriting the existing data stored in that record.

[xxibmehrab]

thank you so much, I have a test tomorrow and I didn't know why not just sort instead of indexing.. hopefully I'll go good

[mohammadahmedragab]

thank you so much for this valuable helpful video

[mamedk]

Thank you for explaining this 🙏 Helped me

[b.petrushchak]

Thank you for an interesting intoro to the indexing concept.

[hansmartinhanken]

Thanks @Brian! A good intro to indexing.

[mau_lopez]

Great explanation, very clear, just what I was looking for right now. Thanks a lot

[TurtlGAmnG]

Excellent explanation of Index. Thanks. 

[chidinwaka]

Very well explained, thank you very much.

[gchehabayesa]

Thanks for the explanation. The only con I see is that to generate an index you first need to scan the whole thing. But I guess its pro as that you only have to scan once.

[juandefelix]

Thanks for the video!! It was very helpful!

[haowenxu]

Thank you, very nice example and explanation

[baatar]

What I've understood is that an index is used to find specific records of data quickly. The index is a separate, independent data structure that you can look through regarding a specific value, such as the company number in your example. The index structure for all the company numbers appears to be ordered. This way, someone can go through the values in order so they can quickly find the specific company number they are looking for. Once they've found the number, the index will point to the specific record in the database that it is referring to. The index structure is also nice because you can easily realize when you've exhausted your search for the company number you're looking for because if you stumble upon a different value, that means your search is over.

[AgriAasan]

Create index not give that much fast...in my table i use more
AS is it slow the execution time ? if this is the pblm give any suggesstion

[benripka]

x1.5 speed is a must for this one. Good video though! thanks man.