Understanding SAP HANA

SAP HANA is a revolutionary platform based in the company’s new In-memory database.Learning it implies choosing to pursue a career path that is both fulfilling and exciting to work with. I am honored that you chose TeachMeHANA to assist you on this journey. TeachMeHANA delivers a series of tutorials designed for beginners that will steadily and surely make you an expert in the subject.

For those of you who are new to SAP, do read my post – What is SAP ?

Question before we go further – What is an In-Memory database?

An In-memory database is one that stores all of its data online or in its memory.Confused? Let’s explain this again with the most played out analogy.Now picture yourself turning on your laptop. You now want to work on a word document.

What do you do? Simple. Find that blue icon and give it a click. Then comes the wait.

The wait may be of a few seconds or more based on your configurations. After it opens, now close the program. Now go open it again. The wait this time would be really less at least compared to the first time you started it.  What brought around this mystical change?


As shown in the figure, there are 3 components of your computer here. For your CPU to start executing your program, the required information should be available in your RAM. If the program was not called recently, the information would not be available here and would need to be picked up from the persistent disk – your hard drive. Consequently, when you call a program for the first time, the information is loaded to the RAM and then processed by the CPU. The second time when you called it, it was already there in the RAM and hence got processed really fast.

RAM access is really fast and any data present there is referred to as data in-memory.

Your hard disk storage is relatively slower in access but offers cheaper storage. The size of your RAM is a crucial factor in deciding how much of data you can keep In-memory and access really fast. But unfortunately, it’s not practical to expand the RAM size of a PC to be able to house all the data you access.


Realizing this, the good folks at SAP created an in-memory database that keeps all of the customer data online/in-memory. So, in a way you could picture this as a gigantic RAM running multiple cores of CPUs and hence delivering lightning fast response times.

Now before you throw your disks out for being a disappointment, it’s important to understand that the RAM is volatile memory, i.e. it loses its data on loss of power. Thus, it’s important for backups to be taken to persistent disks. Backups are scheduled jobs executed as per the configurations to make sure no data is lost in case of SAP HANA DB down times.



How exactly do Backups happen? We’ll discuss that in a different post.

The beauty of SAP HANA lies in the fact that it does most of its calculations in-memory at the database layer instead of the application layer as done traditionally. SAP HANA is not just a database. It consists of different engines that crunch calculations efficiently and return results to the application layer.

Due to this push-down of logic, the data latency (Time taken between request and response) is really small and that’s where the true magic lies.

SAP HANA opens up possibilities that were unimaginable with a traditional database which range from real-time status reporting of your inventories, online analysis of streaming data from sensors, unrivaled predictive analysis capabilities and many more.

Since you have taken the first step towards a career in SAP HANA, let me tell you exciting roads lie ahead.

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Happy Learning!

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  1. Simple English,

    I’m Currently working in JD Edwards Domain as a (Techno/Developer and Admin/ CNC) but my plans are to settle in SAP-DB side, i found your website from (Quora) :).

    I found your website a very good start to know what is SAP and HANA.

    Thank you sir.

    • Glad you liked it.
      I have great plans for this website. Need to finish it soon.
      Comments like yours keep me motivated.

    • Hi Anel,

      I am also working in JD Edwards(User Admin/CNC), I am planning to learn SAP HANA and move into it. How difficult to get a job with my current experience(1 year, 9 months)? Is it a right idea? Could you please suggest me.


  2. Hi Shyam, Liked the content, currently working as a SAP MDM Consultant(Techno Functional) so i think HANA is the way forward, Combining your tutorials with the Open SAP courses give many insights into HANA, Thanks for the help, you’re doing a amazing job.

    • Happy to know that these tutorials are helping everyone. Please share this documents on social media to show your support for this website. Thanks!

    • SAP HANA Developer guide is the only source I trust. The links may change so its best if you google it. Also check open.sap.com . And also, I would say finish everything on my website first. A beginner always wants to learn everything but my website focuses on everything you need in regular real-time project. Any special requirements can easily be searched in the developer guide once your foundations are strong. Try to take one source of information and finish it end to end. Take my site or any other but finish it from that source and practice the examples given before you search around for more.

    • Open.sap.com has video tutorials. I would love to create tutorials on YouTube but with the limited time I have every week, I want to finish the written tutorials set with case studies. Video and text formats of tutorials both have their own level of effectiveness but text is my preferred method for now. I would suggest that you finish all of TeachMeHANA tutorials and let me know if you have gaps in understanding. I can create specific articles explaining them better. But firstly, finish everything here 🙂 and get a system and practice, practice, practice. There’s no book/article/video good enough to teach you HANA.. it only comes when you practice and bang your head against the wall solving errors.

  3. Fantastic tutorial shyam. very informative. I do not have any background on SAP but still it is very much understandable. I am looking forward for more SAP related stuff from you in future.

  4. Thank you Syam for this Blog. You have taught us last year on SAP BW on HANA here in Manila. Happy to find you blog which is a refresher on the knowledge you shared that week since it was really informative. Looking forward for BW on HANA tutorials here in your blog as well 🙂

    • Joan, nice to hear from you again. Yes.. BW on HANA is also in my list of things to do. But BW is such a large topic which needs a lot of time to write and publish. Once I finish all the native HANA tutorials, I do plan on starting BW as well. So maybe in the upcoming months.. Thanks for your feedback.

  5. Hi,
    How many types of transformation in SLT system.?
    can we filter data in SLT before loading data into target..?
    Max size of a input parameter ?
    if we are getting data from oracle ,some data type are not present in HANA then how we have to change and where we have change the datatype in HANA ?

    • Hi Nabi,
      Sorry for the late reply. I hope you already found the answer but I’ll reply anyways.
      SLT is usually used for 1:1 mapping of data. That means that the raw data from the source comes to the SAP HANA database in real-time. But it has the capability to do minor transformations like filtering data, hiding fields, combining datasets.etc..
      But it is always recommended to not do these transformations in SLT and have them done in HANA because that’s where the true processing capabilities are. SLT is rarely used for any type of transformations. Plus, as a developer, you would ideally not have any access to the SLT application as well. All you would do is ask the SLT administrators for the tables you want for your development.
      2. Max size of input parameter depends on the datatype you are creating it on. For example, if the input parameter is NVARCHAR type, it would have a limit of 5000 characters which is the limit of this datatype. You can find these limits in SAP documentation.
      3. Data types would always be available. SLT maintains datatype mappings for all supported sources. These settings can be changed of course but are best left untouched.

      Hope this clears your doubts.

  6. Excellent Shyam!! This is really very helpful for all the HANA developers and for the people who wants to learn HANA in detail. Thanks a lot for the great work.

  7. 1. As per performance wise, which join is better Referential or Left Outer Join? Why?
    2. After replicating data, there is mismatch number of records in source system and hana system then how you will resolve it?
    3. As per performance wise, which one is better Attribute View or Dimenstion Calculation view? Why?
    4. What is the landscape in SLT?
    5. Once we created ATV, ANV and CV. To which reporting tool these views available ( Webi or Microsoft Excel or lumira)
    6. What is the Sidecar in HANA?
    7. How you are using SLT in your HANA system like is it seperate server?

    • Hi,
      Firstly, as an advice to everyone new to HANA, please understand that you must choose a clear path of what you want to do in HANA. Do you wish to be a developer or an Admin? This site is aimed mostly towards teaching SAP HANA development and the admin parts that are good to know.
      I say this because you try to dwell too deep into SLT which is not required since a developer usually requests tables to the admin team who then assigns it in a replicating state. If you are a developer, a high level overview of what SLT is should be enough.
      Now, let’s speak about your questions.
      1. Left outer join is the best join which can be used in terms of performance. Referential join is a better performing version of an inner join but should ideally never be used because it requires the referential integrity to be maintained which is dangerous territory to tread in. Check my tutorial on Join types where I’ve discussed this in detail.
      2. There is a delta Queue monitor in SLT under the transaction ODQMON where you can analyze and recover lost data. As a developer, you do not need to get into all this.
      3. Forget about attribute and analytical views. Only Calculation views are the path forward. AV and ANV can be considered obsolete.
      4. SLT is just a server in between the source system and SAP HANA. It uses an RFC connection when connecting to SAP Sources and DB Connection to SAP HANA target. It also can perform minor transformations which is usually not used since calculations are preferred to be done in SAP HANA. Again, no need to get too deep into all this is you wish to be a HANA developer instead of an admin.
      5. Of these 3, only CV should be used for development as per SAP’s path forward. All reporting tools can connect to it. Just that the connectivity types might differ. Keep checking the reporting section of this website where I am demonstrating how different reporting tools connect to CVs. There are already documents there but it might take another month to fully finish based on my current bandwidth.
      6. HANA Sidecar is a scenario in HANA implementation wherein the client decides to keep their existing BI solution but only move one or more functional modules to SAP HANA. For example, if a client decides to move only the FI (Financie) module’s data models and subsequent reporting to be based on SAP HANA sources. This helps the client do a kind of proof of concept to check if it would provide a good return on investment or not.
      7. SLT is usually always a separate server even though you can install it on an ECC system too but that is not recommended.

      Hope this clarifies your doubts.

  8. Hi Shyam,
    Its a great website for beginners to understand the HANA concepts in nutshell. Would be great if you can also include XSJS, XSODATA and their consumption from SAPUI5. That would give an end to end perspective of how HANA can be used in a development environment.

  9. Hey Mate,

    The articles are written in simple English and very easily understandable. Good job. I have started working on SAP HANA now. Looking forward to for more of your articles.

    • It was there on the right side pane on every tutorial.. but today, the plugin corrupted and this disappeared. Will have to restore some backup files. Should be fixed by today.

  10. Hello, excellent documentation on Hana ..
    Kindly incorporate calculation view .. type cube with star join..


      • Sure..I have already informed to my friends.. Now i am looking into the next sessions…Keep update the tutorials..and keep learning..Thanks,

  11. Hi shyamuthaman please dont mind me asking this question ,Iam new to HANA world .I want to know what profile will i be targeting after going through the course is it more of administration or developer .I want to focus on developer side of HANA .please reply if possible thank you .

  12. Hi Shyam,

    I have a very basic question – could you please explain how a Dialog step works in HANA ? How data flows from Front End to HANA & Back – interalia this would help us better understand the architecture. Thanks, John

    • Push down refers to the process by which the filters get applied before data is pulled from a database. It restricts unwanted data from flowing up and thereby slowing the process.

  13. hello Sir,
    i read your blog. Its most clear and best across all available blogs. I wanted to ask you that what are the certifications available in sap hana? Is content on your blog enough to do any certification? I have little experience in SAP SD (no certification). Please Reply.
    Thank you.

  14. This explanation was very good. Any beginner can easily understand it. Thanks for sharing it and documenting patiently. Keep doing more of this kind of content. It is very very useful.

    Thanks a lot again !!!!


  15. Hi
    I am going to take admission in georgian@ilac campus toronto canada in SUPPLY CHAIN MANAGEMENT COURSE.

    I want to learn SAP software in Supply Chain .

    where should I start and what’s best software for that ? Can anyone help me in this .

    also is there SAP available for free to practice?


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