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  • storing data for maps database

    - by Timigen
    I am working on an application that displays choropleth maps. These maps are of all different types, some display state by county, country by state/province, or world by country. How should I handle storing the map information in the database? My Thoughts: I won't need to do queries to find POI inside a region, so I don't think there is a need to use spatial datatypes. I am considering storing a map as a geoJSON object (I am using JS mapping library that accepts geoJSON). The only issue is what if I want a map of the US northeast. Then I would have geoJSON for the US and a separate one for the US northeast, which would be redundant. Would it make sense to have a shape database where I had each state then when I needed a map of the US I could query for each state, and when I needed a map of the US Northeast I could again query for what I need? Note: I am not concerned with storing the data for each region, just the region itself. I will query for the data on the fly for the specific region.

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  • How to make this sub-sub-query work?

    - by Josh Weissbock
    I am trying to do this in one query. I asked a similar question a few days ago but my personal requirements have changed. I have a game type website where users can attend "classes". There are three tables in my DB. I am using MySQL. I have four tables: hl_classes (int id, int professor, varchar class, text description) hl_classes_lessons (int id, int class_id, varchar lessonTitle, varchar lexiconLink, text lessonData) hl_classes_answers (int id, int lesson_id, int student, text submit_answer, int percent) hl_classes stores all of the classes on the website. The lessons are the individual lessons for each class. A class can have infinite lessons. Each lesson is available in a specific term. hl_classes_terms stores a list of all the terms and the current term has the field active = '1'. When a user submits their answers to a lesson it is stored in hl_classes_answers. A user can only answer each lesson once. Lessons have to be answered sequentially. All users attend all "classes". What I am trying to do is grab the next lesson for each user to do in each class. When the users start they are in term 1. When they complete all 10 lessons in each class they move on to term 2. When they finish lesson 20 for each class they move on to term 3. Let's say we know the term the user is in by the PHP variable $term. So this is my query I am currently trying to massage out but it doesn't work. Specifically because of the hC.id is unknown in the WHERE clause SELECT hC.id, hC.class, (SELECT MIN(output.id) as nextLessonID FROM ( SELECT id, class_id FROM hl_classes_lessons hL WHERE hL.class_id = hC.id ORDER BY hL.id LIMIT $term,10 ) as output WHERE output.id NOT IN (SELECT lesson_id FROM hl_classes_answers WHERE student = $USER_ID)) as nextLessonID FROM hl_classes hC My logic behind this query is first to For each class; select all of the lessons in the term the current user is in. From this sort out the lessons the user has already done and grab the MINIMUM id of the lessons yet to be done. This will be the lesson the user has to do. I hope I have made my question clear enough.

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  • DB2 upgrade database Fails due to descriptor corruption

    - by Jdcc
    Hi Everyone, I've recently upgraded my DB2 9.5 to DB2 9.7, and I am unable to update my database to v9.7. The error I have been receiving is this: "SQL0901N The SQL statement failed because of a non-severe system error. Subsequent SQL statements can be processed. (Reason "Packed descriptor corruption found. Please run RUNSTATS on this table".) SQLSTATE=58004" I have tried to connect with 9.5 clients that worked before the "upgrade" on other machines, but they complain about the DB not being migrated to the current version. So my DB is now somewhere in limbo between 9.5 and 9.7. Would anyone have any clever ideas on how to execute runstats on this DB without being able to connect to it? I'm not concerned so much about the data inside, as I am about the settings (name,optimization stuff, etc) Please let me know if I there is any information I left out. Thanks, Jdcc

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  • Windows 7 Phone Database – Querying with Views and Filters

    - by SeanMcAlinden
    I’ve just added a feature to Rapid Repository to greatly improve how the Windows 7 Phone Database is queried for performance (This is in the trunk not in Release V1.0). The main concept behind it is to create a View Model class which would have only the minimum data you need for a page. This View Model is then stored and retrieved rather than the whole list of entities. Another feature of the views is that they can be pre-filtered to even further improve performance when querying. You can download the source from the Microsoft Codeplex site http://rapidrepository.codeplex.com/. Setting up a view Lets say you have an entity that stores lots of data about a game result for example: GameScore entity public class GameScore : IRapidEntity {     public Guid Id { get; set; }     public string GamerId {get;set;}     public string Name { get; set; }     public Double Score { get; set; }     public Byte[] ThumbnailAvatar { get; set; }     public DateTime DateAdded { get; set; } }   On your page you want to display a list of scores but you only want to display the score and the date added, you create a View Model for displaying just those properties. GameScoreView public class GameScoreView : IRapidView {     public Guid Id { get; set; }     public Double Score { get; set; }     public DateTime DateAdded { get; set; } }   Now you have the view model, the first thing to do is set up the view at application start up. This is done using the following syntax. View Setup public MainPage() {     RapidRepository<GameScore>.AddView<GameScoreView>(x => new GameScoreView { DateAdded = x.DateAdded, Score = x.Score }); } As you can see, using a little bit of lambda syntax, you put in the code for constructing a single view, this is used internally for mapping an entity to a view. *Note* you do not need to map the Id property, this is done automatically, a view model id will always be the same as it’s corresponding entity.   Adding Filters One of the cool features of the view is that you can add filters to limit the amount of data stored in the view, this will dramatically improve performance. You can add multiple filters using the fluent syntax if required. In this example, lets say that you will only ever show the scores for the last 10 days, you could add a filter like the following: Add single filter public MainPage() {     RapidRepository<GameScore>.AddView<GameScoreView>(x => new GameScoreView { DateAdded = x.DateAdded, Score = x.Score })         .AddFilter(x => x.DateAdded > DateTime.Now.AddDays(-10)); } If you wanted to further limit the data, you could also say only scores above 100: Add multiple filters public MainPage() {     RapidRepository<GameScore>.AddView<GameScoreView>(x => new GameScoreView { DateAdded = x.DateAdded, Score = x.Score })         .AddFilter(x => x.DateAdded > DateTime.Now.AddDays(-10))         .AddFilter(x => x.Score > 100); }   Querying the view model So the important part is how to query the data. This is done using the repository, there is a method called Query which accepts the type of view as a generic parameter (you can have multiple View Model types per entity type) You can either use the result of the query method directly or perform further querying on the result is required. Querying the View public void DisplayScores() {     RapidRepository<GameScore> repository = new RapidRepository<GameScore>();     List<GameScoreView> scores = repository.Query<GameScoreView>();       // display logic } Further Filtering public void TodaysScores() {     RapidRepository<GameScore> repository = new RapidRepository<GameScore>();     List<GameScoreView> todaysScores = repository.Query<GameScoreView>().Where(x => x.DateAdded > DateTime.Now.AddDays(-1)).ToList();       // display logic }   Retrieving the actual entity Retrieving the actual entity can be done easily by using the GetById method on the repository. Say for example you allow the user to click on a specific score to get further information, you can use the Id populated in the returned View Model GameScoreView and use it directly on the repository to retrieve the full entity. Get Full Entity public void GetFullEntity(Guid gameScoreViewId) {     RapidRepository<GameScore> repository = new RapidRepository<GameScore>();     GameScore fullEntity = repository.GetById(gameScoreViewId);       // display logic } Synchronising The View If you are upgrading from Rapid Repository V1.0 and are likely to have data in the repository already, you will need to perform a synchronisation to ensure the views and entities are fully in sync. You can either do this as a one off during the application upgrade or if you are a little more cautious, you could run this at each application start up. Synchronise the view public void MyUpgradeTasks() {     RapidRepository<GameScore>.SynchroniseView<GameScoreView>(); } It’s worth noting that in normal operation, the view keeps itself in sync with the entities so this is only really required if you are upgrading from V1.0 to V2.0 when it gets released shortly.   Summary I really hope you like this feature, it will be great for performance and I believe supports good practice by promoting the use of View Models for specific pages. I’m hoping to produce a beta for this over the next few days, I just want to add some more tests and hopefully iron out any bugs. I would really appreciate any thoughts on this feature and would really love to know of any bugs you find. You can download the source from the following : http://rapidrepository.codeplex.com/ Kind Regards, Sean McAlinden.

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  • extreme slowness with a remote database in Drupal

    - by ceejayoz
    We're attempting to scale our Drupal installations up and have decided on some dedicated MySQL boxes. Unfortunately, we're running into extreme slowness when we attempt to use the remote DB - page load times go from ~200 milliseconds to 5-10 seconds. Latency between the servers is minimal - a tenth or two of a millisecond. PING 10.37.66.175 (10.37.66.175) 56(84) bytes of data. 64 bytes from 10.37.66.175: icmp_seq=1 ttl=64 time=0.145 ms 64 bytes from 10.37.66.175: icmp_seq=2 ttl=64 time=0.157 ms 64 bytes from 10.37.66.175: icmp_seq=3 ttl=64 time=0.157 ms 64 bytes from 10.37.66.175: icmp_seq=4 ttl=64 time=0.144 ms 64 bytes from 10.37.66.175: icmp_seq=5 ttl=64 time=0.121 ms 64 bytes from 10.37.66.175: icmp_seq=6 ttl=64 time=0.122 ms 64 bytes from 10.37.66.175: icmp_seq=7 ttl=64 time=0.163 ms 64 bytes from 10.37.66.175: icmp_seq=8 ttl=64 time=0.115 ms 64 bytes from 10.37.66.175: icmp_seq=9 ttl=64 time=0.484 ms 64 bytes from 10.37.66.175: icmp_seq=10 ttl=64 time=0.156 ms --- 10.37.66.175 ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 8998ms rtt min/avg/max/mdev = 0.115/0.176/0.484/0.104 ms Drupal's devel.module timers show the database queries aren't running any slower on the remote DB - about 150 microseconds whether it's the local or the remote server. Profiling with XHProf shows PHP execution times that aren't out of whack, either. Number of queries doesn't seem to make a difference - we seem the same 5-10 second delay whether a page has 12 queries or 250. Any suggestions about where I should start troubleshooting here? I'm quite confused.

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  • Big Data – Buzz Words: Importance of Relational Database in Big Data World – Day 9 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned what is HDFS. In this article we will take a quick look at the importance of the Relational Database in Big Data world. A Big Question? Here are a few questions I often received since the beginning of the Big Data Series - Does the relational database have no space in the story of the Big Data? Does relational database is no longer relevant as Big Data is evolving? Is relational database not capable to handle Big Data? Is it true that one no longer has to learn about relational data if Big Data is the final destination? Well, every single time when I hear that one person wants to learn about Big Data and is no longer interested in learning about relational database, I find it as a bit far stretched. I am not here to give ambiguous answers of It Depends. I am personally very clear that one who is aspiring to become Big Data Scientist or Big Data Expert they should learn about relational database. NoSQL Movement The reason for the NoSQL Movement in recent time was because of the two important advantages of the NoSQL databases. Performance Flexible Schema In personal experience I have found that when I use NoSQL I have found both of the above listed advantages when I use NoSQL database. There are instances when I found relational database too much restrictive when my data is unstructured as well as they have in the datatype which my Relational Database does not support. It is the same case when I have found that NoSQL solution performing much better than relational databases. I must say that I am a big fan of NoSQL solutions in the recent times but I have also seen occasions and situations where relational database is still perfect fit even though the database is growing increasingly as well have all the symptoms of the big data. Situations in Relational Database Outperforms Adhoc reporting is the one of the most common scenarios where NoSQL is does not have optimal solution. For example reporting queries often needs to aggregate based on the columns which are not indexed as well are built while the report is running, in this kind of scenario NoSQL databases (document database stores, distributed key value stores) database often does not perform well. In the case of the ad-hoc reporting I have often found it is much easier to work with relational databases. SQL is the most popular computer language of all the time. I have been using it for almost over 10 years and I feel that I will be using it for a long time in future. There are plenty of the tools, connectors and awareness of the SQL language in the industry. Pretty much every programming language has a written drivers for the SQL language and most of the developers have learned this language during their school/college time. In many cases, writing query based on SQL is much easier than writing queries in NoSQL supported languages. I believe this is the current situation but in the future this situation can reverse when No SQL query languages are equally popular. ACID (Atomicity Consistency Isolation Durability) – Not all the NoSQL solutions offers ACID compliant language. There are always situations (for example banking transactions, eCommerce shopping carts etc.) where if there is no ACID the operations can be invalid as well database integrity can be at risk. Even though the data volume indeed qualify as a Big Data there are always operations in the application which absolutely needs ACID compliance matured language. The Mixed Bag I have often heard argument that all the big social media sites now a days have moved away from Relational Database. Actually this is not entirely true. While researching about Big Data and Relational Database, I have found that many of the popular social media sites uses Big Data solutions along with Relational Database. Many are using relational databases to deliver the results to end user on the run time and many still uses a relational database as their major backbone. Here are a few examples: Facebook uses MySQL to display the timeline. (Reference Link) Twitter uses MySQL. (Reference Link) Tumblr uses Sharded MySQL (Reference Link) Wikipedia uses MySQL for data storage. (Reference Link) There are many for prominent organizations which are running large scale applications uses relational database along with various Big Data frameworks to satisfy their various business needs. Summary I believe that RDBMS is like a vanilla ice cream. Everybody loves it and everybody has it. NoSQL and other solutions are like chocolate ice cream or custom ice cream – there is a huge base which loves them and wants them but not every ice cream maker can make it just right  for everyone’s taste. No matter how fancy an ice cream store is there is always plain vanilla ice cream available there. Just like the same, there are always cases and situations in the Big Data’s story where traditional relational database is the part of the whole story. In the real world scenarios there will be always the case when there will be need of the relational database concepts and its ideology. It is extremely important to accept relational database as one of the key components of the Big Data instead of treating it as a substandard technology. Ray of Hope – NewSQL In this module we discussed that there are places where we need ACID compliance from our Big Data application and NoSQL will not support that out of box. There is a new termed coined for the application/tool which supports most of the properties of the traditional RDBMS and supports Big Data infrastructure – NewSQL. Tomorrow In tomorrow’s blog post we will discuss about NewSQL. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Create my own database system

    - by Xananax
    Ok so before I get bashed: I know it's something huge for one person; I don't care if the end product can actually be used or not. I need to learn how databases work in order to use them more efficiently, and my way of learning is by doing. So I want to create my own database system. I am not referring to creating a pseudo-database that would use query to parse files; this would simply be a filesystem interface with a query language. I am talking about the actual structure of a database engine. And since what I have in mind is neither relational nor document-oriented (it's "node-oriented", if that even exists), I would need any resource to be as abstract and high-level as possible. So how would I go about creating that? What resources/tutorials/books can I read to understand? The language does not matter in the slightest. Ideally, the code would be pseudo-code to illustrate the concept, not tied to a particular language, but anything would do. I was not able to find anything on the matter on google (since I am so illiterate on the subject, maybe I am just not entering the right search). If such resources are not available, then I guess something about how to create a client would at least be a step in the right direction.

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  • Partner Webcast – More out of Database Appliance with DB Options - 13 September 2012

    - by Thanos
    The Oracle Database Appliance is a new way to take advantage of the world's most popular database—Oracle Database 11g —in a single, easy-to-deploy and manage system. It's a complete package of software, server, storage, and networking that's engineered for simplicity; saving time and money by simplifying deployment, maintenance, and support of database workloads. But that is not all, with the support for all Oracle Database Options, Oracle Database Appliance can be the ideal solution for many use cases. Feature Benefit Simplifies deployment, maintenance, and support of high-availability database workloads Saves significant time and effort throughout the database administration lifecycle An engineered system of software, server, storage, and networking High availability for a wide range of custom and packaged OLTP and data warehousing application databases Simple one-button Installation, full-stack integrated patching and diagnostics Reduces planned and unplanned downtime by automatically monitoring and logging service requests with Oracle Support Built using the world’s #1 database Protects databases from server and storage failures with Oracle Real Application Clusters and Automatic Storage Management Unique Pay-As-You-Grow software licensing Reduces cost with flexibility to adjust your software spend as your business grows without the need for any hardware upgrades Discover the Oracle Database Appliance Value Proposition and learn how to position and combine it with database options to capture new business and easily roll out solutions safely and with maximum cost efficiency. This webcast is repeated once again for your benefit. Agenda: Oracle Database& Engineered Systems Innovation. What’s the Oracle Database Appliance ? Oracle Database Appliance Value Proposition. Oracle Database Appliance with Database Options Oracle Database Appliance Partners Business Delivery FormatThis FREE online LIVE eSeminar will be delivered over the Web. Registrations received less than 24hours prior to start time may not receive confirmation to attend. Duration: 1 hour Register Now! Oracle Database Appliance is available for purchase at the Oracle Store under Engineered Systems. For any questions please contact us at partner.imc-AT-beehiveonline.oracle-DOT-com Visit regularly our ISV Migration Center blog Or Follow us @oracleimc to learn more on Oracle Technologies as well as upcoming partner webcasts and events.

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  • Document-oriented vs Column-oriented database fit

    - by user1007922
    I have a data-intensive application that desperately needs a database make-over. The general data model: There are records with RIDs, grouped together by group IDs (GID). The records have arbitrary data fields, (maybe 5-15) with a few of them mandatory and the rest optional, and thus sparse. The general use model: There are LOTS and LOTS of Writes. Millions to Billions of records are stored. Very often, they are associated with new GIDs, but sometimes, they are associated with existing GIDs. There aren't as many reads, but when they happen, they need to be pretty fast or at least constant speed regardless of the database size. And when the reads happen, it will need to retrieve all the records/RIDs with a certain GID. I don't have a need to search by the record field values. Primarily, I will need to query by the GID and maybe RID. What database implementation should I use? I did some initial research between document-oriented and column-oriented databases and it seems the document-oriented ones are a good fit, model-wise. I could store all the records together under the same document key using the GID. But I don't really have any use for their ability to search the document contents itself. I like the simplicity and scalability of column-oriented databases like Cassandra, but how should I model my data in this paradigm for optimal performance? Should my key be the GID and should I create a column for each record/RID? (there maybe thousands or hundreds of thousands of records in a group/GID). Or should my key be the RID and ensure each row has a column for the GID value? What results in faster writes and reads under this model?

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  • Can I use access used by Visual Basic for building a database [on hold]

    - by user3413537
    I am the only programmer where I work (summer job) and I am a student with only a few years of programming experience. So I was asked to build a database and I am very excited about this project because hopefully I can learn a lot from this. Using this database my manager is supposed to be able to assign work (dealing with businesses) to different people within the company using an interface (all workers have a shared drive). When workers are done with that paperwork related to the business, they can check off that its done, add comments at the bottom of the interface, and then move on to the next business. The only experience I've had with databases is some querying with SQL, and I've built GUI interfaces with JAVA. The information on the interface will be populated from Excel so workers know what businesses they are dealing with. I've done some research and I believe the best way to build this would be building a GUI using Microsoft Visual Studio (Visual Basic) first, then figuring out a way to populate the Interface from Excel. Also because the data is pretty straight forward and not complicated I will be using MS Access to store and track the database. I know this won't be easy, but for all you geniuses out there, is this on the right path? Thanks.

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  • SQL SERVER – Fastest Way to Restore the Database

    - by pinaldave
    A few days ago, I received following email: “Pinal, We are in an emergency situation. We have a large database of around 80+ GB and its backup is of 50+ GB in size. We need to restore this database ASAP and use it; however, restoring the database takes forever. Do you think a compressed backup would solve our problem? Any other ideas you got?” First of all, the asker has already answered his own question. Yes; I have seen that if you are using a compressed backup, it takes lesser time when you try to restore a database. I have previously blogged about the same subject. Here are the links to those blog posts: SQL SERVER – Data and Page Compressions – Data Storage and IO Improvement SQL SERVER – 2008 – Introduction to Row Compression SQL SERVER – 2008 – Introduction to New Feature of Backup Compression However, if your database is very large that it still takes a few minutes to restore the database even though you use any of the features listed above, then it will really take some time to restore the database. If there is urgency and there is no time you can spare for restoring the database, then you can use the wonderful tool developed by Idera called virtual database. This tool restores a certain database in just a few seconds so it will readily be available for usage. I have in depth written my experience with this tool in the article here SQL SERVER – Retrieve and Explore Database Backup without Restoring Database – Idera virtual database. Let me know your experience in this scenario. Have you ever needed your database backup restored very quickly, what did you do in that scenario. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Backup and Restore, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Oracle Database 12c: Partner Material

    - by Thanos Terentes Printzios
    Oracle Database 12c offers the latest innovation from Oracle Database Server Technologies with a new Multitenant Architecture, which can help accelerate database consolidation and Cloud projects. The primary resource for Partners on Database 12c is of course the Oracle Database 12c Knowledge Zone where you can get up to speed on the latest Database 12c enhancements so you can sell, implement and support this. Resources and material on Oracle Database 12c can be found all around Oracle.com, but even hidden in AR posters like the one on the left. Here are some additional resources for you Oracle Database 12c: Interactive Quick Reference is a multimedia tool for various terms and concepts used in the Oracle Database 12c release. This reference was built as a multimedia web page which provides descriptions of the database architectural components, and references to relevant documentation. Overall, is a nice little tool which may help you quickly to find a view you are searching for or to get more information about background processes in Oracle Database 12c. Use this tool to find valuable information for any complex concept or product in an intuitive and useful manner. Oracle Database 12c Learning Library contains several technical traininings (2-day DBA, Multitenant Architecture, etc) but also Videos/Demos, Learning Paths by Role and a lot more. Get ready and become an Oracle Database 12c Specialized Partner with the Oracle Database 12c Specialization for Partners. Review the Specialization Criteria, your company status and apply for an Oracle Database 12c Specialization. Access our OPN training repository to get prepared for the exams. "Oracle Database 12c: Plug into the Cloud!"  Marketing Kit includes a great selection of assets to help Oracle partners in their marketing activities to promote solutions that leverage all the new features of Oracle Database 12c. In the package you will find assets (templates, invitation texts, presentations, telemarketing script,...) to be used for your demand generation activities; a full set of presentations with the value propositions for customers; and Sales Enablement and Sales Support material. Review here and start planning your marketing activities around Database 12c. Oracle Database 12c Quick Reference Guide (PDF) and Oracle Database 12c – Partner FAQ (PDF) Partners that need further assistance with Database 12c can always contact us at partner.imc-AT-beehiveonline.oracle-DOT-com or locally address one the Oracle ECEMEA Partner Hubs for assistance.

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  • Predicting advantages of database denormalization

    - by Janus Troelsen
    I was always taught to strive for the highest Normal Form of database normalization, and we were taught Bernstein's Synthesis algorithm to achieve 3NF. This is all very well and it feels nice to normalize your database, knowing that fields can be modified while retaining consistency. However, performance may suffer. That's why I am wondering whether there is any way to predict the speedup/slowdown when denormalizing. That way, you can build your list of FD's featuring 3NF and then denormalize as little as possible. I imagine that denormalizing too much would waste space and time, because e.g. giant blobs are duplicated or it because harder to maintain consistency because you have to update multiple fields using a transaction. Summary: Given a 3NF FD set, and a set of queries, how do I predict the speedup/slowdown of denormalization? Link to papers appreciated too.

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  • Best approach for a database of long strings

    - by gsingh2011
    I need to store questions and answers in a database. The questions will be one to two sentences, but the answers will be long, at least a paragraph, likely more. The only way I know about to do this right now is an SQL database. However, I don't feel like this is a good solution because as far as I've seen, these databases aren't used for data of this type or size. Is this the correct way to go or is there a better way to store this data? Is there a better way than storing raw strings?

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  • Is it necessary to create a database with as few tables as possible

    - by Shaheer
    Should we create a database structure with a minimum number of tables? Should it be designed in a way that everything stays in one place or is it okay to have more tables? Will it in anyway affect anything? I am asking this question because a friend of mine modified some database structure in mediaWiki. In the end, instead of 20 tables he was using only 8, and it took him 8 months to do that (it was his college assignment). EDIT I am concluding the answer as: size of the tables does NOT matter, until the case is exceptional; in which case the denormalization may help. Thanks to everyone for the answers.

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  • ???????????I/O?SSD????!

    - by Yusuke.Yamamoto
    ????? ??:2010/11/25 ??:???? ?????????????????????I/O???????????????? Oracle Database 11g Release 2 ?????Database Smart Flash Cache?????????????????????????????????????????????????????? ???????????????????SSD????????????"?????(??)"???????????????????? Database Smart Flash Cache ???OLTP??+?????????????????OLTP??+OLTP???10????????? ????????? ????????????????? http://oracletech.jp/products/pickup/000076.html

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  • SQL SERVER – Quiz and Video – Introduction to Basics of a Query Hint

    - by pinaldave
    This blog post is inspired from SQL Architecture Basics Joes 2 Pros: Core Architecture concepts – SQL Exam Prep Series 70-433 – Volume 3. [Amazon] | [Flipkart] | [Kindle] | [IndiaPlaza] This is follow up blog post of my earlier blog post on the same subject - SQL SERVER – Introduction to Basics of a Query Hint – A Primer. In the article we discussed various basics terminology of the query hints. The article further covers following important concepts of query hints. Expecting Seek and getting a Scan Creating an index for improved optimization Implementing the query hint Above three are the most important concepts related to query hint and SQL Server.  There are many more things one has to learn but without beginners fundamentals one can’t learn the advanced  concepts. Let us have small quiz and check how many of you get the fundamentals right. Quiz 1) You have the following query: DECLARE @UlaChoice TinyInt SET @Type = 1 SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice You have a nonclustered index named IX_Legal_Ula on the UlaChoice field. The Primary key is on the ID field and called PK_Legal_ID 99% of the time the value of the @UlaChoice is set to ‘YP101′. What query will achieve the best optimization for this query? SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice WITH(INDEX(X_Legal_Ula)) SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice WITH(INDEX(PK_Legal_ID)) SELECT * FROM LegalActivity WHERE UlaChoice = @UlaChoice OPTION (Optimize FOR(@UlaChoice = ‘YP101′)) 2) You have the following query: SELECT * FROM CurrentProducts WHERE ShortName = ‘Yoga Trip’ You have a nonclustered index on the ShortName field and the query runs an efficient index seek. You change your query to use a variable for ShortName and now you are using a slow index scan. What query hint can you use to get the same execution time as before? WITH LOCK FAST OPTIMIZE FOR MAXDOP READONLY Now make sure that you write down all the answers on the piece of paper. Watch following video and read earlier article over here. If you want to change the answer you still have chance. Solution 1) 3 2) 4 Now compare let us check the answers and compare your answers to following answers. I am very confident you will get them correct. Available at USA: Amazon India: Flipkart | IndiaPlaza Volume: 1, 2, 3, 4, 5 Please leave your feedback in the comment area for the quiz and video. Did you know all the answers of the quiz? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Move Database Files MDF and LDF to Another Location

    - by pinaldave
    When a novice DBA or Developer create a database they use SQL Server Management Studio to create new database. Additionally, the T-SQL script to create a database is very easy as well. You can just write CREATE DATABASE DatabaseName and it will create new database for you. The point to remember here is that it will create the database at the default location specified for SQL Server Instance (this default instance can be changed and we will see that in future blog posts). Now, once the database goes in production it will start to grow. It is not common to keep the Database on the same location where OS is installed. Usually Database files are on SAN, Separate Disk Array or on SSDs. This is done usually for performance reason and manageability perspective. Now the challenges comes up when database which was installed at not preferred default location and needs to move to a different location. Here is the quick tutorial how you can do it. Let us assume we have two folders loc1 and loc2. We want to move database files from loc1 to loc2. USE MASTER; GO -- Take database in single user mode -- if you are facing errors -- This may terminate your active transactions for database ALTER DATABASE TestDB SET SINGLE_USER WITH ROLLBACK IMMEDIATE; GO -- Detach DB EXEC MASTER.dbo.sp_detach_db @dbname = N'TestDB' GO Now move the files from loc1 to loc2. You can now reattach the files with new locations. -- Move MDF File from Loc1 to Loc 2 -- Re-Attached DB CREATE DATABASE [TestDB] ON ( FILENAME = N'F:\loc2\TestDB.mdf' ), ( FILENAME = N'F:\loc2\TestDB_log.ldf' ) FOR ATTACH GO Well, we are done. There is little warning here for you: If you do ROLLBACK IMMEDIATE you may terminate your active transactions so do not use it randomly. Do it if you are confident that they are not needed or due to any reason there is a connection to the database which you are not able to kill manually after review. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Structuring database for multi-object "activity" and "following" functionalities

    - by romaninsh
    I am working on a web application which operate with different types of objects such as user, profiles, pages etc. All objects have unique object_id. When objects interact it may produce "activity", such as user posting on the page or profile. Activity may be related to multiple objects through their object_id. Users may also follow "objects" and they need to be able to see stream of relevant activity. Could you provide me with some data structure suggestions which would be efficient and scalable? My goal is to show activity limited to the objects which user is following I am not limited by relational databases. Update As I'm getting advices on ORM and how index things, I'd like to again, stress my question. According to my current design model the database structure looks like this: As you can see - it's quite easy to implement database like that. Activity and Follower tables do contain much larger amount of records than the upper level but it's tolerable. But when it comes for me to create a "timeline" table, it becomes a nightmare. For every user I need to reference all the object activities which he follows. In terms of records it easily gets out of control. Please suggest me how to change this structure to avoid timeline creation and also be abel to quickly retrieve activity for any given user. Thanks.

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  • Database Schema Usage

    - by CrazyHorse
    I have a question regarding the appropriate use of SQL Server database schemas and was hoping that some database gurus might be able to offer some guidance around best practice. Just to give a bit of background, my team has recently shrunk to 2 people and we have just been merged with another 6 person team. My team had set up a SQL Server environment running off a desktop backing up to another desktop (and nightly to the network), whilst the new team has a formal SQL Server environment, running on a dedicated server, with backups and maintenance all handled by a dedicated team. So far it's good news for my team. Now to the query. My team designed all our tables to belong to a 3-letter schema name (e.g. User = USR, General = GEN, Account = ACC) which broadly speaking relate to specific applications, although there is a lot of overlap. My new team has come from an Access background and have implemented their tables within dbo with a 3-letter perfix followed by "_tbl" so the examples above would be dbo.USR_tblTableName, dbo.GEN_tblTableName and dbo.ACC_tblTableName. Further to this, neither my old team nor my new team has gone live with their SQL Servers yet (we're both coincidentally migrating away from Access environments) and the new team have said they're willing to consider adopting our approach if we can explain how this would be beneficial. We are not anticipating handling table updates at schema level, as we will be using application-level logins. Also, with regards to the unwieldiness of the 7-character prefix, I'm not overly concerned myself as we're using LINQ almost exclusively so the tables can simply be renamed in the DMBL (although I know that presents some challenges when we update the DBML). So therefore, given that both teams need to be aligned with one another, can anyone offer any convincing arguments either way?

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  • SQL – Quick Start with Explorer Sections of NuoDB – Query NuoDB Database

    - by Pinal Dave
    This is the third post in the series of the blog posts I am writing about NuoDB. NuoDB is very innovative and easy-to-use product. I can clearly see how one can scale-out NuoDB with so much ease and confidence. In my very first blog post we discussed how we can install NuoDB (link), and in my second post I discussed how we can manage the NuoDB database transaction engines and storage managers with a few clicks (link). Note: You can Download NuoDB from here. In this post, we will learn how we can use the Explorer feature of NuoDB to do various SQL operations. NuoDB has a browser-based Explorer, which is very powerful and has many of the features any IDE would normally have. Let us see how it works in the following step-by-step tutorial. Let us go to the NuoDBNuoDB Console by typing the following URL in your browser: http://localhost:8080/ It will bring you to the QuickStart screen. Make sure that you have created the sample database. If you have not created sample database, click on Create Database and create it successfully. Now go to the NuoDB Explorer by clicking on the main tab, and it will ask you for your domain username and password. Enter the username as a domain and password as a bird. Alternatively you can also enter username as a quickstart and password as a quickstart. Once you enter the password you will be able to see the databases. In our example we have installed the Sample Database hence you will see the Test database in our Database Hierarchy screen. When you click on database it will ask for the database login. Note that Database Login is different from Domain login and you will have to enter your database login over here. In our case the database username is dba and password is goalie. Once you enter a valid username and password it will display your database. Further expand your database and you will notice various objects in your database. Once you explore various objects, select any database and click on Open. When you click on execute, it will display the SQL script to select the data from the table. The autogenerated script displays entire result set from the database. The NuoDB Explorer is very powerful and makes the life of developers very easy. If you click on List SQL Statements it will list all the available SQL statements right away in Query Editor. You can see the popup window in following image. Here is the cool thing for geeks. You can even click on Query Plan and it will display the text based query plan as well. In case of a SELECT, the query plan will be much simpler, however, when we write complex queries it will be very interesting. We can use the query plan tab for performance tuning of the database. Here is another feature, when we click on List Tables in NuoDB Explorer.  It lists all the available tables in the query editor. This is very helpful when we are writing a long complex query. Here is a relatively complex example I have built using Inner Join syntax. Right below I have displayed the Query Plan. The query plan displays all the little details related to the query. Well, we just wrote multi-table query and executed it against the NuoDB database. You can use the NuoDB Admin section and do various analyses of the query and its performance. NuoDB is a distributed database built on a patented emergent architecture with full support for SQL and ACID guarantees.  It allows you to add Transaction Engine processes to a running system to improve the performance of your system.  You can also add a second Storage Engine to your running system for redundancy purposes.  Conversely, you can shut down processes when you don’t need the extra database resources. NuoDB also provides developers and administrators with a single intuitive interface for centrally monitoring deployments. If you have read my blog posts and have not tried out NuoDB, I strongly suggest that you download it today and catch up with the learnings with me. Trust me though the product is very powerful, it is extremely easy to learn and use. Reference: Pinal Dave (http://blog.sqlauthority.com)   Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: NuoDB

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  • Oracle Database 12c: Oracle Multitenant Option

    - by hamsun
    1. Why ? 2. What is it ? 3. How ? 1. Why ? The main idea of the 'grid' is to share resources, to make better use of storage, CPU and memory. If a database administrator wishes to implement this idea, he or she must consolidate many databases to one database. One of the concerns of running many applications together in one database is: ‚what will happen, if one of the applications must be restored because of a human error?‘ Tablespace point in time recovery can be used for this purpose, but there are a few prerequisites. Most importantly the tablespaces are strictly separated for each application. Another reason for creating separated databases is security: each customer has his own database. Therefore, there is often a proliferation of smaller databases. Each of them must be maintained, upgraded, each allocates virtual memory and runs background processes thereby wasting resources. Oracle 12c offers another possibility for virtualization, providing isolation at the database level: the multitenant container database holding pluggable databases. 2. What ? Pluggable databases are logical units inside a multitenant container database, which consists of one multitenant container database and up to 252 pluggable databases. The SGA is shared as are the background processes. The multitenant container database holds metadata information common for pluggable databases inside the System and the Sysaux tablespace, and there is just one Undo tablespace. The pluggable databases have smaller System and Sysaux tablespaces, containing just their 'personal' metadata. New data dictionary views will make the information available either on pdb (dba_views) or container level (cdb_views). There are local users, which are known in specific pluggable databases and common users known in all containers. Pluggable databases can be easily plugged to another multitenant container database and converted from a non-CDB. They can undergo point in time recovery. 3. How ? Creating a multitenant container database can be done using the database configuration assistant: There you find the new option: Create as Container Database. If you prefer ‚hand made‘ databases you can execute the command from a instance in nomount state: CREATE DATABASE cdb1 ENABLE PLUGGABLE DATABASE …. And of course this can also be achieved through Enterprise Manager Cloud. A freshly created multitenant container database consists of two containers: the root container as the 'rack' and a seed container, a template for future pluggable databases. There are 4 ways to create other pluggable databases: 1. Create an empty pdb from seed 2. Plug in a non-CDB 3. Move a pdb from another pdb 4. Copy a pdb from another pdb We will discuss option2: how to plug in a non_CDB into a multitenant container database. Three different methods are available : 1. Create an empty pdb and use Datapump in traditional export/import mode or with Transportable Tablespace or Database mode. This method is suitable for pre 12c databases. 2. Create an empty pdb and use GoldenGate replication. When the pdb catches up with the non-CDB, you fail over to the pdb. 3. Databases of Version 12c or higher can be plugged in with the help of the new dbms_pdb Package. This is a demonstration for method 3: Step1: Connect to the non-CDB to be plugged in and create an xml File with description of the database. The xml file is written to $ORACLE_HOME/dbs per default and contains mainly information about the datafiles. Step 2: Check if the non-CDB is pluggable in the multitenant container database: Step 3: Create the pluggable database, connected to the Multitenant container database. With nocopy option the files will be reused, but the tempfile is created anew: A service is created and registered automatically with the listener: Step 4: Delete unnecessary metadata from PDB SYSTEM tablespace: To connect to newly created pdb, edit tnsnames.ora and add entry for new pdb. Connect to plugged-in non_CDB and clean up Data Dictionary to remove entries now maintained in multitenant container database. As all kept objects have to be recompiled it will take a few minutes. Step 5: The plugged-in database will be automatically synchronised by creating common users and roles when opened the first time in read write mode. Step 6: Verify tablespaces and users: There is only one local tablespace (users) and one local user (scott) in the plugged-in non_CDB pdb_orcl. This method of creating plugged_in non_CDB from is fast and easy for 12c databases. The method for deplugging a pluggable database from a CDB is to create a new non_CDB and use the the new full transportable feature of Datapump and drop the pluggable database. About the Author: Gerlinde has been working for Oracle University Germany as one of our Principal Instructors for over 14 years. She started with Oracle 7 and became an Oracle Certified Master for Oracle 10g and 11c. She is a specialist in Database Core Technologies, with profound knowledge in Backup & Recovery, Performance Tuning for DBAs and Application Developers, Datawarehouse Administration, Data Guard and Real Application Clusters.

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  • Database users in the Oracle Utilities Application Framework

    - by Anthony Shorten
    I mentioned the product database users fleetingly in the last blog post and they deserve a better mention. This applies to all versions of the Oracle Utilities Application Framework. The Oracle Utilities Application Framework uses up to three users initially as part of the base operations of the product. The type of database supported (the framework supports Oracle, IBM DB2 and Microsoft SQL Server) dictates the number of users used and their permissions. For publishing brevity I will outline what is available for the Oracle database and, in summary, mention where it differs for the other database supported. For Oracle database customers we ship three distinct database users: Administration User (SPLADM or CISADM by default) - This is the database user that actually owns the schema. This user is not used by the product to do any DML (Data Manipulation Language) SQL other than that is necessary for maintenance of the database. This database user performs all the DCL (Data Control Language) and DDL (Data Definition Language) against the database. It is typically reserved for Database Administration use only. Product Read Write User (SPLUSER or CISUSER by default) - This is the database user used by the product itself to execute DML (Data Manipulation Language) statements against the schema owned by the Administration user. This user has the appropriate read and write permission to objects within the schema owned by the Administration user. For databases such as DB2 and SQL Server we may not create this user but use other DCL (Data Control Language) statements and facilities to simulate this user. Product Read User (SPLREAD or CISREAD by default) - This is the database that has read only permission to the schema owned by the Administration user. It is used for reporting or any part of the product or interface that requires read permissions to the database (for example, products that have ConfigLab and Archiving use this user for remote access). For databases such as DB2 and SQL Server we may not create this user but use other DCL (Data Control Language) statements and facilities to simulate this user. You may notice the words by default in the list above. The values supplied with the installer are the default and can be changed to what the site standard or implementation wants to use (as long as they conform to the standards supported by the underlying database). You can even create multiples of each within the same database and pointing to same schema. To manage the permissions for the users, there is a utility provided with the installation (oragensec (Oracle), db2gensec (DB2) or msqlgensec (SQL Server)) that generates the security definitions for the above users. That can be executed a number of times for each schema to give users appropriate permissions. For example, it is possible to define more than one read/write User to access the database. This is a common technique used by implementations to have a different user per access mode (to separate online and batch). In fact you can also allocate additional security (such as resource profiles in Oracle) to limit the impact of specific users at the database. To facilitate users and permissions, in Oracle for example, we create a CISREAD role (read only role) and a CISUSER role (read write role) that can be allocated to the appropriate database user. When the security permissions utility, oragensec in this case, is executed it uses the role to determine the permissions. To give you a case study, my underpowered laptop has multiple installations on it of multiple products but I have one database. I create a different schema for each product and each version (with my own naming convention to help me manage the databases). I create individual users on each schema and run oragensec to maintain the permissions for each appropriately. It works fine as long I have setup the userids appropriately. This means: Creating the users with the appropriate roles. I use the common CISUSER and CISREAD role across versions and across Oracle Utilities Application Framework products. Just remember to associate the CISUSER role with the database user you want to use for read/write operations and the CISREAD role with the user you wish to use for the read only operations. The role is treated as a tag to indicate the oragensec utility which appropriate permissions to assign to the user. The utilities for the other database types essentially do the same, obviously using the technology available within those databases. Run oragensec against the read write user and read only user against the appropriate administration user (I will abbreviate the user to ADM user). This ensures the right permissions are allocated to the right users for the right products. To help me there, I use the same prefix on the user name for the same product. For example, my Oracle Utilities Application Framework V4 environment has the administration user set to FW4ADM and the associated FW4USER and FW4READ as the users for the product to use. For my MWM environment I used MWMADM for the administration user and MWMUSER and MWMREAD for my associated users. You get the picture. When I run oragensec (once for each ADM user), I know what other users to associate with it. Remember to rerun oragensec against the users if I run upgrades, service packs or database based single fixes. This assures that the users are in synchronization with the ADM user. As a side note, for those who do not understand the difference between DML, DCL and DDL: DDL (Data Definition Language) - These are SQL statements that define the database schema and the structures within. SQL Statements such as CREATE and DROP are examples of DDL SQL statements. DCL (Data Control Language) - These are the SQL statements that define the database level permissions to DDL maintained objects within the database. SQL Statements such as GRANT and REVOKE are examples of DCL SQL statements. DML (Database Manipulation Language) - These are SQL statements that alter the data within the tables. SQL Statements such as SELECT, INSERT, UPDATE and DELETE are examples of DML SQL statements. Hope this has clarified the database user support. Remember in Oracle Utilities Application Framework V4 we enhanced this by also supporting CLIENT_IDENTIFIER to allow the database to still use the administration user for the main processing but make the database session more traceable.

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  • SQL SERVER – Shard No More – An Innovative Look at Distributed Peer-to-peer SQL Database

    - by pinaldave
    There is no doubt that SQL databases play an important role in modern applications. In an ideal world, a single database can handle hundreds of incoming connections from multiple clients and scale to accommodate the related transactions. However the world is not ideal and databases are often a cause of major headaches when applications need to scale to accommodate more connections, transactions, or both. In order to overcome scaling issues, application developers often resort to administrative acrobatics, also known as database sharding. Sharding helps to improve application performance and throughput by splitting the database into two or more shards. Unfortunately, this practice also requires application developers to code transactional consistency into their applications. Getting transactional consistency across multiple SQL database shards can prove to be very difficult. Sharding requires developers to think about things like rollbacks, constraints, and referential integrity across tables within their applications when these types of concerns are best handled by the database. It also makes other common operations such as joins, searches, and memory management very difficult. In short, the very solution implemented to overcome throughput issues becomes a bottleneck in and of itself. What if database sharding was no longer required to scale your application? Let me explain. For the past several months I have been following and writing about NuoDB, a hot new SQL database technology out of Cambridge, MA. NuoDB is officially out of beta and they have recently released their first release candidate so I decided to dig into the database in a little more detail. Their architecture is very interesting and exciting because it completely eliminates the need to shard a database to achieve higher throughput. Each NuoDB database consists of at least three or more processes that enable a single database to run across multiple hosts. These processes include a Broker, a Transaction Engine and a Storage Manager.  Brokers are responsible for connecting client applications to Transaction Engines and maintain a global view of the network to keep track of the multiple Transaction Engines available at any time. Transaction Engines are in-memory processes that client applications connect to for processing SQL transactions. Storage Managers are responsible for persisting data to disk and serving up records to the Transaction Managers if they don’t exist in memory. The secret to NuoDB’s approach to solving the sharding problem is that it is a truly distributed, peer-to-peer, SQL database. Each of its processes can be deployed across multiple hosts. When client applications need to connect to a Transaction Engine, the Broker will automatically route the request to the most available process. Since multiple Transaction Engines and Storage Managers running across multiple host machines represent a single logical database, you never have to resort to sharding to get the throughput your application requires. NuoDB is a new pioneer in the SQL database world. They are making database scalability simple by eliminating the need for acrobatics such as sharding, and they are also making general administration of the database simpler as well.  Their distributed database appears to you as a user like a single SQL Server database.  With their RC1 release they have also provided a web based administrative console that they call NuoConsole. This tool makes it extremely easy to deploy and manage NuoDB processes across one or multiple hosts with the click of a mouse button. See for yourself by downloading NuoDB here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: CodeProject, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology Tagged: NuoDB

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