Crystal Reports: Advanced Tutorials
Advanced Database Concepts / Database Verification
Subtitles of the Movie (Crystal Reports: Advanced / Advanced Database Concepts / Database Verification)
Errors occur in data, some errors can be catastrophic, others just simply effect the computer system itself. Because we're so dependent on our information however, reducing the amount of these errors is crucial. Now errors occur at several times. It can happen when the data is captured, when it's initially collected, when it's transmitted from one system to another, or even when it's been processed by the actual software program itself. What happens is that the data can be corrupted. Remember, when we're working with our data, we're actually capturing a series on ones and zeros. Now let's say for instance that we have just a minor corruption, we have three bits of data that were being transferred over, and the characters did not get changed over correctly. Let's say for instance in an ASCII format, one zero got kicked out in the background. Well, this could result in a difference between IC and T becoming HG and V. The data just got shifted over. Now we need to do as much as possible to actually avoid these transition errors. This is why we have such things as Parity Checks. We also will ask people to verify their data. Now in our database programs, the verification is usually automatic, but I would like you to be aware of the fact, that we must do this verification. Almost every database program out, comes with a type of verification program. What it's doing is it's looking to see if the data is still in it's original format. I've gone into a program that is called QuickBooks. QuickBooks is an accounting database, although QuickBooks will have a different screenshot, the concepts are still the same in all of our databases. I'm going to go to the File, and down to Utilities. In Utilities is where I'll find Verify the Data, and Rebuild the Data. Now if I'm verifying the data itself, it's actually not going to do any corrections, it's simply going to tell me, yes I found an error, or no your data is correct. If the data is correct, nothing to worry about. If there's a storm, if there's a hiccup in electricity, whenever we have these unusual events, we really try to verify our data to make sure it's okay. It does not take much with electricity and computers to have a little hiccup in the program. When I rebuild data, it is always going to ask for a backup, this is in case it tries to fix some type of an error, that actually corrupts the program even more. Remember, it's trying to fix an issue, sometimes they cannot be fixed, and we have to go back to a backup. So in this case, I'm going to say, let's just do a local backup. The minute I do, it's going to take us to our verification screen. Now here you'll notice that I'll have different formats of the verification. A complete means that it'll take a long period of time, but it's really going to go in, and look to see, if the data is reasonable. It looks for unusual characters, it looks for any corruption within the data itself. Now if I do a quicker verification, it's only looking for key system commands. Your program will run, the database will come up, but here's where you'll go in, and notice garbage as your results. Sometimes we start getting error messages in our calculations, that's because the system files were okay, it never looked at the actual data in each field. If you have the time, we always encourage complete verification, but remember with the amount of data that we have in the office, this is hard to do. Very often when we're using a database throughout the day, when we copy data over, we do no verification whatsoever. Now this is for speed, this is so that you can get your data real time. Sooner or later however, we have to do the full maintenance. It should go without saying, that when we're doing these verifications, you're not going to be using your data. When you're working with Crystal, I'd like you to be aware of this verification process. Ask around, make sure that you're taking whatever steps necessary to protect your database, so there are no surprises when you're using Crystal Reports.
Tutorial Information
| Course: | Crystal Reports: Advanced |
| Author: | Lauri Sowa-Matson |
| SKU: | 34268 |
| ISBN: | 978-1-61866-016-9 |
| Release Date: | 2011-09-30 |
| Duration: | 7.5 hrs / 100 lessons |
| Work Files: |
Yes |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
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