What is Cardinality and High Cardinality and Low Cardinality in Oracle SQL Tutorial SQL Tutorial for beginners PLSQL Tutorial PLSQL Tutorial for beginners PL/SQL Tutorial PL SQL Tutorial PL SQL Tutorial for beginners PL/SQL Tutorial for beginners Oracle SQL Tutorial
Views: 1212 TechLake
Donate!: http://bit.ly/DonateCTVM2. Cardinality is the maximum number of connections a row of one table can have with row(s) of another table. This is basically just a fancy word to describe the two options: 1, or many. Designing the cardinality shows us whether the relationship is a one-to-one relationship or a one-to-many relationship. In the event of a logical many-to-many relationship, the cardinality would be best designed as two separate one-to-many relationships with the intermediary table in the middle (see my video over many-to-many relationships). Learn more about cardinality here: https://www.calebcurry.com/blogs/database-design/cardinality-and-modality Courses for Download: http://www.udemy.com/u/calebcurry/ Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://Twitter.com/calebCurry Subscribe (it's free!): http://bit.ly/PqPyvH Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 44200 Caleb Curry
When it comes to writing efficient queries there are a few key concepts that need to be understood. One of them is the Oracle Cost-Based Optimizer (CBO). Although it's called a cost-based optimizer it's actually not the cost we need to focus on primarily to understand why the optimizer makes certain decisions. In this webinar, you will learn the basics of the CBO, see why it is crucial that the optimizer's picture of the data fits reality, why cardinality and selectivity estimates matter so muc
Views: 58806 Redgate Videos
Cardinality feedback, introduced with Oracle Database 11g, has been significantly enhanced with 12c. Cardinality feedback allows the CBO to learn from a cardinality estimate mistake and re-optimize the execution plan. Learn more in this free SQL Tuning tutorial. See all free Oracle Database tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3194 SkillBuilders
n this video you will understand what is an SQL profile and how does it help in SQL plan generation and execution. The entire course on Interpreting an AWR report is available at udemy https://www.udemy.com/oracle-database-troubleshooting-and-tuning You can use Coupon Code YOUTUBETT for discount Our Upcoming Online Course Schedule is available in the url below https://docs.google.com/spreadsheets/d/1qKpKf32Zn_SSvbeDblv2UCjvtHIS1ad2_VXHh2m08yY/edit#gid=0 Reach us at [email protected]
Views: 2553 Ramkumar Swaminathan
Do you use EXPLAIN PLAN to tune Oracle SQL? Does it always "tell the truth", or does it "lie". (Maybe it's not the whole truth!) In this free tutorial from SkillBuilders' Oracle Certified Master John Watson, you will learn why the execution plan generated by EXPLAIN PLAN can be misleading and what to do about it. After a brief lecture, John demonstrates exactly why. You'll hear about dynamic sampling, adaptive cursor sharing (11g), adaptive execution plans (12c) and of course, bind variables. John demonstrates how bind variables cause misleading execution plans using dbms_xplan.display and dbms_xplan.display_cursor. To get the most from this tutorial, you should have some understanding of hard parse, soft parse, cardinality, histograms. See all SkillBuilders FREE Oracle Database tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3488 SkillBuilders
In this free tutorial you will learn how to generate and read (interpret) an execution plan in Oracle Databases. See more FREE Oracle Tuning tutorials at http://skillbuilders.com/free-oracle-tutorials. Understanding what the Oracle Database does with your SQL is essential to tuning - and the execution plan is the key. Oracle Certified Master DBA John Watson will provide a brief introduction (4 minutes) - which includes John's tuning methodology, then demonstrate EXPLAIN PLAN, SQL*Plus AUTOTRACE and DBMS_XPLAN.DISPLAY_CURSOR. In the tutorial, John will teach you: - How to read an execution plan - Find the 1st step in the plan - Decipher the order of the steps in the plan - That EXPLAIN PLAN can be very misleading Prerequisites: To get the most from this tutorial, you should: 1 Know how to code SQL 2 Be familiar with SQL*Plus 3 Know - in very general terms - what an execution plan is. 4 Have a basic understanding of the Library Cache (this is where Oracle Database stores parsed SQL statements) 5 Have a basic understanding of the Cost Based Optimizer (this is the part of the database that parses your SQL, creates an execution plan. Hopefully the correct - most efficient - plan).
Views: 66349 SkillBuilders
In this video I describe how you can use Oracle's DBMS_XPLAN.DISPLAY_CURSOR to examine the execution plan for a SQL statement that has recently been executed and determine if that plan is optimal or not and where you might be able to optimize it.
Views: 9881 Maria Colgan
Best Buy Links (affiliate): SQL The Complete Reference https://amzn.to/2NAfr2G SQL Cookbook (Covers SQL Server, PostgrSQL, Oracle, MySQL, And Db2) https://amzn.to/2MhU6Xl Beginning SQL Queries https://amzn.to/2NzaAPj SQL, PL/SQL the Programming Language of Oracle https://amzn.to/2QjIyWH SQL in easy steps https://amzn.to/2x73t6G T-SQL Fundamentals https://amzn.to/2NywZfC Microsoft SQL Server 2012 Step By Step https://amzn.to/2O8BMBI ----------------------------------- WHAT ARE KEYS DEGREE AND CARDINALITY IN DATABASE IN HINDI
Views: 182 LearnEveryone
Learn how to use Oracle Virtual Private Database (VPD) to secure your data. See all lessons at http://skillbuilders.com/12c-TSDP-Tutorial First, Virtual Private Database. What is it? Answer: It's a declarative technique for enforcing security. Typically, it's based on user application context. That was the first limitation of 8i. Backed with 8i context were session-specific. The context variables were sort in the PGA. That means you simply couldn't use this in a web environment. However, global context, with use of 9i, Virtual Private Database became usable for web applications with connection pooling. But whether you're using it to client server or on a three tier environment, it's declarative technique rather than a programmatic technique. I can go behind the back of the application as a DBA and generate predicates to get appended to all SQLs. Select, insert, update, delete the end users. Issue the SQL and I will generate a predicate that filters the access. It's impossible to bypass. All users will have predicates appended to all their code. It doesn't matter whether they're using SQL Plus, Discoverer, Business Objects, Crystal Reports, eBusiness Suites, whatever they're using, I as DBA can filter their access to roles. The end result, different users see different data sets while running the same code and accessing the same tables, hence, the name Virtual Private Database. Different users will think they're seeing a totally different set of tables, but in fact it's one column database, one set of tables hosting a single application shared by all the users. The mechanism - you can apply VPD to tables, to views, to synonyms, and a declarative technique. Once the technique you write a function that generates the predicate, you associate the function with the table. From then on whenever the user issue SQL against that table the Cost-Based Optimizer rewrites the code. The Cost-Based Optimizer rewrites the user SQL to call the function to generate the predicate. The predicate is then appended to the SQL and it's the modified SQL that is parsed and executed. Let's see how this actually works. I'm working here by the way. This is just a perfectly normal 12.1 database. But what I'm going to demonstrate at this point will in fact work on 11g as well. I'm not going to be using any of the 12c enhancements to VPD for this little demonstration. I'll work in the scott schema. What do we have to do? We write a function to generate the predicate string. Create function. And I'll my function vpdf. The function must conform to a fixed specification. It must take two varchar arguments. One of the arguments is intended to be the schema to which the function will be applied. The other argument is the object within the schema to which the function will be applied. And it must return a varchar2, which is the generated predicate. Let's begin. Within this function you can do just about anything. There are some limitations. It's impossible for the function to query or update the table against which the VPD calls here is going to be applied or we violate the rules of purity that we come across so often with PL/SQL. But apart from that, it can do just about anything - including a number of dreadful side effects can be introduced by writing VPD functions. I'm going to do a very simple one on this one. I'll shall simple return immediately a predicate. What predicate? Ename, which is the ename column from this scott.emp table. Ename should equal sys_context. I'll go to the local context, my user end context, and just extract session user. We can see that John has tested this earlier today and therefore the object already was suggesting and he's just dropping it now and cleaning up the recreate. I hope you realize these really are live demonstrations. I'm not just running scripts. I've created a function. What's that function going to do? It's going to return this value here. Test it. Always test it and see what it's actually going to do. I'll select vpdf. I have to give it a couple of arguments. This one will do for now.
Views: 4570 SkillBuilders
In this video you will learn how the SQL Optimizer uses Density information to compute default cardinality estimations Twitter: http://www.twitter.com/SQLMaestros Twitter: http://www.twitter.com/A_Bansal http://www.SQLMaestros.com http://www.amitbansal.net
Views: 3088 SQLMaestros
The fifth part of a mini-series of videos showing how you can improve the performance of function calls from SQL. In this episode, we compare the performance of conventions table functions with pipelined table functions. For more information see: https://oracle-base.com/articles/misc/pipelined-table-functions https://oracle-base.com/articles/misc/efficient-function-calls-from-sql Website: https://oracle-base.com Blog: https://oracle-base.com/blog Twitter: https://twitter.com/oraclebase Cameo by Mike Dietrich : Blog: https://blogs.oracle.com/UPGRADE Twitter: https://twitter.com/MikeDietrichDE Cameo appearances are for fun, not an endorsement of the content of this video.
Views: 12094 ORACLE-BASE.com
Tom Kyte introduces adaptive execution plans followed by a demo. "Adaptive Plans" in SQL Tuning Guide" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL221 "Controlling Adaptive Optimization" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL257 "Generating and Displaying SQL Execution Plans" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=TGSQL271 "Keeping Your Database Secure" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=DBSEG009
Views: 14131 OracleDBVision
The SQL Server query optimizer uses distribution statistics when creating a query plan. The statistics provide information about the distribution of column values across participating rows, helping the optimizer better estimate the number of rows, or cardinality, of the query results. Cardinality (SQL statements) In SQL (Structured Query Language), the term cardinality refers to the uniqueness of data values contained in a particular column (attribute) of a database table. The lower the cardinality, the more duplicated elements in a column
Views: 325 SqlIsEasy
Hello friends in this video i'm just showing to you what is optimizer statistics into oracle,optimizer help to improve the performance of sql statements during execution period. #ORACLEWORLD #OptimizerStatistics Oracle database Unbeatable,Unbreakable Platform.
Views: 2368 Oracle World
Learn how to create an Entity Relationship Diagram in this tutorial. We provide a basic overview of ERDs and then gives step-by-step training on how to make an ER diagram with correct cardinality. Entity Relationship Diagrams are comprised of 3 main categories: entities, attributes, and relationships. Entities are objects or concepts that are associated with important data—like a customer, order, or product. Attributes represent properties or traits of an entity, such as a customer’s phone number or home address. Relationships demonstrate the link between entities. Another main aspect of of ERD's is cardinality, which further defines the relationship between entities in a numerical way. Certain symbols signify the minimum and maximum relationship between different entities. Additional ERD information: https://www.lucidchart.com/pages/entity-relationship-diagram-tutorial —— Learn more and sign up: https://www.lucidchart.com/users/register Follow us: Facebook: https://www.facebook.com/lucidchart Twitter: https://twitter.com/lucidchart Instagram: https://www.instagram.com/lucidchart LinkedIn: https://www.linkedin.com/company/lucidsoftware
Views: 670848 Lucidchart
Understanding Explain Plans is an excerpt from Oracle SQL Performance Tuning for Developers: http://www.informit.com/store/oracle-sql-performance-tuning-for-developers-livelessons-9780134117027 6+ Hours of Video Instruction The focus of Oracle SQL Performance Tuning for Developers LiveLessons is to illustrate coding techniques that ensure a consistent response time between instances and releases of the Oracle database. This course works closely with performance tuning of actual SQL statements. Description In this video training, Dan Hotka starts out with a complete overview of the Oracle architecture so students can get an understanding how their SQL and applications can take advantage of the computing environment. This course then goes in-depth on understanding and controlling the Explain Plan, which is how and in what order Oracle retrieves data. The discussion includes considerable detail, with SQL examples, on how the optimizers--both rule-based and cost-based, but mostly cost-based--make their decisions. Students will work with a variety of SQL statements, reviewing Explain Plans and making changes to make these SQL statements perform better. Lectures include index design, using hints and coding style to control the Explain Plans, and how to use useful tools such as index monitoring, SQL Trace, and the PL/SQL profiler. This LiveLessons course takes a close look at indexes: how Oracle selects them, why they are sometimes not used, and how to tell if indexes are being used. This course includes Oracle10g, Oracle11g, and Oracle12c SQL tuning topics. Skill Level Intermediate Learn How To Read and understand Explain Plan content Review an Explain Plan and tell quickly if this is a good plan Understand a good index column candidate from a not-so-good candidate Quickly tell the likelihood if your SQL will use an existing index Use coding and a variety of Hints (directives) that can produce better performing SQL Execute and interpret SQL trace output Who Should Take This Course Oracle programmers Oracle database administrators who need additional training on SQL tuning Course Requirements Working knowledge of the SQL query language http://www.informit.com/store/oracle-sql-performance-tuning-for-developers-livelessons-9780134117027
Views: 3436 LiveLessons
Learn the new 12c options for creating histograms. See all free video tutorials at http://www.skillbuilders.com/free-oracle-tutorials. In this free tutorial, Oracle Certified Master DBA John Watson demonstrates what histograms do (provide correct cardinality), the difference between histogram types (Frequency and Height Balanced). You will also learn the importance of the auto sample size algorithm in 12c and the new "Hybrid" and "Top Frequency" type histograms.
Views: 3726 SkillBuilders
SQL Monitoring is the best new feature of Oracle 11g for performance analysts, developers and support teams. Finally there is a tool that provides the most accurate, useful and interesting information when a SQL statement is running for longer than expected in a clear format with no minimal advance configuration requirements: What execution plan is really being used? What row source cardinality calculations are incorrect? What steps in the plan are taking the most time and consuming most resources? In this presentation, Doug Burns will demonstrate the various ways of accessing SQL Monitoring functionality and use example reports to show how the information can be used to analyse both currently running and completed statements. It will also describe and offer solutions to some of the minor quirks you might encounter. For our complete archive, and to sign up for upcoming webinars please go to http://www.red-gate.com/oracle-webinars
Views: 5228 Redgate Videos
For More Tutorials Related To Cisco,CCNA,Microsoft,Oracle,HP,Adobe,IBM,Java And Much More Please Visit This Site http://www.geteveryvideos.com/category/certification-tutorials/
Views: 58201 AllCertifications Tutorials
“External tables can be a fantastic tool for reading files into your database using SQL,” says Oracle SQL Developer advocate Chris Saxon. “However, they can be a bit tricky to work with.” In this 2 Minute Tech Tip recorded at ODTUG Kscope 2018, Chris explains how using the external table parameter override clause can make things a lot less tricky, and, even better, how Oracle Database 18c allows you to create inline external tables. https://developer.oracle.com/ https://cloud.oracle.com/en_US/tryit
Views: 508 Oracle Developers
Topic: Understanding The Execution Plan In this video (part-1) I have explained - The basics of Oracle Execution Plan - How an Execution Plan Looks from SQL Developer, SQL*Plus - How to use Oracle Explain Plan command - Where else one can find Oracle's Execution Plan apart from PLAN_TABLE - Some Examples of Execution Plan - Using DBMS_XPLAN package to format the output while printing the Execution Plan
Views: 6545 Satish Lodam
This is a short video about a feature in SQL Developer which alllow any DBA or developer to compare different execution plans of a SQL Statement. My Blog: https://navneetupnejadba.wordpress.com/ Slideshare: https://www.slideshare.net/navneetupneja1/sql-developer-powerful-free-tool-for-developers-and-dbas
Views: 267 Navneet Upneja
This lecture starts the concept of Entity Relationship Diagramming. It discusses the concept of how to build an ERD and explains the different types of relationships and connections. Entities, Attributes, Relationships, Cardinality, Multiplicity and Participation are explained. This is part 1 of a 2 part lecture.
Views: 14402 Barbara Hecker
what is "rows" in explain plan? Discusses, SQL execution plan A-ROWS vs. E-ROWS concept. Excerpt from "Oracle SQL Tuning Video Tutorial". dbvidya offers oracle sql tuning online training. www.dbvidya.com [email protected] +91 9912323000 Oracle Performance Tuning Online Training : http://www.dbvidya.com/course/perform... Oracle SQL Performance Tuning Training Online : http://www.dbvidya.com/course/sql-tun... Oracle Performance Tuning Videos Tutorial for DBA and Developers : http://www.dbvidya.com/oracle-perform... Oracle AWR Tutorial: http://www.dbvidya.com/course/oracle-... Erwin Tool Online Training : http://www.dbvidya.com/course/erwin-t... ER Data Modeling Course : http://www.dbvidya.com/course/er-mode... Dimensional Modeling Training Online : http://www.dbvidya.com/course/dimensi... Oracle Database Blogs : http://www.dbvidya.com/blog/
Views: 45 DbVidya
This presentation explains how to use basic hints of Oracle. The series of SQL tuning videos presents performance tuning tips for developers. For presentation used in this video, please visit: https://drive.google.com/drive/folders/0B6EDqGZwjejmWng5VWM3ZEtaNzA?usp=sharing
Views: 10984 anilkumar ghorakavi
This video is made especially for students of class XI-XII who have opted Informatics Practices and Computer Science as a subject under the CBSE curriculum. In this, the structure of the CBSE exam paper is discussed and tips are given on how to crack this exam for the subject IP and C++. Contact Me : +91 8800873871 Mail Us : [email protected] Notes link:- https://csandip.blogspot.com/ Google maps:- https://maps.google.com/?cid=7786917265893947860 Must check and give a review
Views: 2317 ROHIT SINGH
This Tutorial will explain fundamentals of Oracle AUTOTRACE. Set up & Use AUTOTRACE. Review PLAN & Statistics generated by AUTOTRACE. Understanding Statistics details.
Views: 23311 Anindya Das
Learn a predictable and repeatable methodology for tuning Oracle SQL statements. Just four steps that you should always follow when tuning an SQL statement. (Note this video does not contain examples of how to apply the four steps, just what the steps are.) Oracle Certified Master John Watson presents. John concludes with a brief overview of how SkillBuilders SQL tuning course provides the information you need to apply the four steps. Learn more about SkillBuilders SQL Tuning course http://skillbuilders.com/oracle-sql-tuning-training 1. What is Oracle doing? (explain plan, trace) 2. Why is Oracle doing it that way? (analyze the execution plan) 3. Is there a better way? Test! 4. If there's a better way, push the CBO towards the better way.
Views: 13702 SkillBuilders
blog: https://connor-mcdonald.com A video to help you understand the "thought process" behind answering AskTom questions. In this episode, how does the optimizer deal with the 12c in-database archiving feature ====================================================== Copyright © 2017 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 721 Connor McDonald
Connect with me or follow me at https://www.linkedin.com/in/durga0gadiraju https://www.facebook.com/itversity https://github.com/dgadiraju https://www.youtube.com/c/TechnologyMentor https://twitter.com/itversity
Views: 31976 itversity
Optimizer needs statistics to create an execution plan for each query.
Views: 58 ORACLE-DBA Workshops
Anju Garg is an Oracle Ace Associate with over 12 years of experience in IT Industry in various roles. Since 2010, she has been involved in teaching and has trained more than a hundred DBAs from across the world in various core DBA technologies like RAC, Data guard, Performance Tuning, SQL statement tuning, Database Administration etc. She is a regular speaker at Sangam and OTNYathra. She also writes articles for All Things Oracle. She is passionate about learning and has keen interest in RAC and Performance Tuning. She shares her knowledge via her technical blog at http://oracleinaction.com/ ABSTRACT--- To improve optimizer estimates in case of skewed data distribution , histograms can be created. Prior to 12c frequency and height balanced histograms could be created. if no. of buckets >= NDV, frequency histogram is created and the optimizer makes correct estimates. If no. of buckets < NDV, height balanced histogram is created and accuracy of optimizer estimates depends on whether a key value is an endpoint or not. The problem of optimizer misestimates in case of height balanced histograms is resolved to a large extent in Oracle Database 12c by introducing top-frequency and hybrid histograms which are created if no. of buckets < NDV. This webinar explores Pre as well post 12c histograms while highlighting the top-frequency and hybrid histograms introduced in Oracle Database 12c.
Views: 3937 AIOUG North India Chapter
Learn how to tune SQL - especially in Data Warehouse environments - with Constraints. Constraints provide critical information to the Cost Based Optimizer in the Oracle Database. Don't drop your constraints for query performance! In these 5 lessons, Oracle Certified Master DBA John Watson will demonstrate how constraints - unique, foreign key, not null - improve the execution plan and thus performance of SQL in an Oracle database. View all 5 lessons, free at http://www.skillbuilders.com/oracle-database-sql-tuning-with-constraints.
Views: 910 SkillBuilders
You're up and running with autotrace, looking at the actual execution plan for a query. Now the real work begins! What is it you're actually looking for in the execution plan? This video shows what you need to investigate and how to use the HotSpot feature of SQL Developer 4.1 to highlight parts of the query you need to pay attention to. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 8245 The Magic of SQL
Learn an Oracle Database 12c new performance feature - Adaptive SQL Plans. During execution, Oracle Database can switch the SQL to a new plan. A very powerful corrective measure! But if you don't know about it , how can you possibly tune SQL in Oracle Database 12c? Time to learn 12c!
Views: 5579 SkillBuilders
Webinar done in 2010 by Oracle ACE Director Daniel Morgan regarding how to read and interpret an Oracle explain plan
Views: 15943 OracleMania
An overview of all the performance tuning and diagnostic features in Oracle SQL Developer including: Explain Plan, Autotrace, SQL Tuning Advsior, Real Time SQL Monitoring, ASH, Monitoring Sessions, and our new Instance Viewer.
Views: 4617 Oracle Database Development Tools
You’ve been writing T-SQL queries for a few years now, and when you have performance issues, you’ve been updating stats and using OPTION (RECOMPILE). It’s served you well, but every now and then, you hit a problem you can’t solve. Your data’s been growing larger, your queries are taking longer to run, and you’re starting to wonder: how can I start getting better query plans? The secret is often comparing the query plan’s estimated number of rows to actual number of rows. If they’re different, it’s up to you – not the SQL Server engine – to figure out why the guesses are wrong. To improve ’em, you can change your T-SQL, the way the data’s structured and stored, or how SQL Server thinks about the data. This session won’t fix every query – but it’ll give you a starting point to understand what you’re looking at, and where to go next as you learn about the Cardinality Estimator. Get full session notes, slides, resources and more here: https://groupby.org/conference-session-abstracts/getting-better-query-plans-by-improving-sqls-estimates/
Views: 1185 GroupBy
Oracle 12c Multi-Threaded Database (parameter threaded_execution=true) provides an fantastic performance improvement by reducing the number of background processes. In this free tutorial, Oracle Certified Master John Watson of SkillBuilders demonstrates how to enable this feature and the resulting performance benefit - in John's demo, a doubling of performance! See all free Oracle 12c tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3751 SkillBuilders