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Oracle Indexes - Beginner
 
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Oracle Indexes - Beginner
Views: 66555 Chris Ostrowski
Oracle New feature 12c  - Multiple Index on same column in oracle
 
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Oracle New feature 12c - Multiple Index on same column in oracle
Views: 178 Siva Academy
Which Order Should Columns Go in an Index?: Finding All the Red Sweets Part 4
 
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When you create an index on multiple columns there's an important question you need to answer: In which order should you list the columns? This video looks at some of the factors you should consider to help answer this question. ============================ 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: 4367 The Magic of SQL
Indexing in Oracle :B-Tree,Bitmap Indexing
 
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This Video is the 1st tutorial in the video series Indexing in Oracle , The video series explains in detail, What are indexes?It's types, what index should be used in which scenario and other important thing in basic terminology. Note :You may want to watch the video with a higher playback speed(1.25 if it suits you more)
Views: 17974 Tech Coach
Multiple Indexes on the Same Set of Columns
 
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This video demonstrates how you can use invisible indexes to allow multiple indexes on the same set of columns. Multiple indexes on the same column set is a new feature in Oracle 12c. For more information see: https://oracle-base.com/articles/12c/multiple-indexes-on-same-set-of-columns-12cr1 Website: https://oracle-base.com Blog: https://oracle-base.com/blog Twitter: https://twitter.com/oraclebase Cameo by Scott Spendolini Blog: http://spendolini.blogspot.co.uk/ Twitter: https://twitter.com/sspendol Website: http://www.sumnertech.com/ Cameo appearances are for fun, not an endorsement of the content of this video.
Views: 1385 ORACLE-BASE.com
SQL 12c Tutorial 20 : SQL 12c Creating Multiple Indexes on column
 
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SQL 12c Tutorial 20 : SQL 12c Creating Multiple Indexes on column SQL 12c New Features SQL 12c Tutorial for beginners Oracle 12c Tutorial for beginners Creating Multiple indexes on column
Views: 935 TechLake
Database Design 39 - Indexes (Clustered, Nonclustered, Composite Index)
 
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This video covers the basics of indexes. Indexing is an extremely important step of database design. Without Indexes database queries can take a substantial amount of time and hog system resources. The main two classifications of indexes are clustered and non-clustered indexes. Clustered indexes are usually the primary key and determine how the data is actually stored in the table. These are the fastest and most effective. Non-clustered indexes sort a reference to data that is still fast but doesn't actually determine how the data is structured. The best tip I can give you is to use indexes but don't over use them. Having loads of indexes on columns that are barely ever in a where clause or join can bog down the database. This is because every time the table is updated the index must also be updated! When a database looks through a table for certain where conditions on a column that does not have an index, it does an entire table scan. This is not a good practice for large databases (or even small databases but not as bad). With an index the database will do an index seek and quickly find the data you are looking for. Composite indexes consist of two or more columns within one index. Use these when you plan on using the two columns together for a database query WHERE clause. Learn more about indexes here: https://www.calebcurry.com/blogs/database-design/introduction-to-indexes Donate!: http://bit.ly/DonateCTVM2. Courses for Download: http://www.udemy.com/u/calebcurry/ (Use the coupon code "YouTubeDiscount" without the quotes) Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://Twitter.com/calebCurry Subscribe (it's free!): https://www.youtube.com/channel/UCZUyPT9DkJWmS_DzdOi7RIA?sub_confirmation=1 Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 98442 Caleb Curry
A Story of Indexes and Full Table Scans: Finding All the Red Sweets Part 1
 
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"Why isn't Oracle using my index?!" is a common question people have when tuning SQL queries. In this episode Chris compares two methods for finding all the red candies from party bags he's prepared. He shows how these are like a full table scan and an index range scan. He goes on to compare the performance of these two approaches. He shows when a full table scan becomes more efficient than an index range scan and vice versa. ============================ 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: 8431 The Magic of SQL
SQL: Indexes - Bit Map & B-trees
 
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In this tutorial, you'll learn when to use b-tree and bitmap index
Views: 54572 radhikaravikumar
What Impact Do Indexes Have on Inserts?: Finding All the Red Sweets Part 0
 
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Creating indexes can improve query performance. Oracle must maintain the indexes however. This increases the work it must do whenever you modify data in indexed columns. In this video Chris looks at this overhead using a real world analogy - recording the color of all the candies stored in party bags! ============================ 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: 2780 The Magic of SQL
07 04 Index Column Order Matters
 
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ORACLE
Views: 103 oracle ocm
07 05 Demo   Index Column Order
 
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ORACLE
Views: 60 oracle ocm
11-How to create an index for a column in a table in a SQL Server database
 
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Original high quality video: http://www.dotnetcodecentral.com/Post/130/microsoft-sql-server-quick-learn-how-to/How-to-create-an-index-for-a-column-in-a-SQL-Server-table All high quality videos on SQL Server (FREE to download): http://www.dotnetcodecentral.com/Technology/microsoft-sql-server-quick-learn-how-to Demonstrates the following (using SQL Server Management Studio): -Open a table in design mode (to modify table structure) -Add an index to a column in a table
Views: 17521 Jagadish Pulakhandam
Indexing JSON Data in Oracle Database 12c
 
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This video gives an overview of indexing JSON data in Oracle database 12c. For more information see: https://oracle-base.com/articles/12c/indexing-json-data-in-oracle-database-12cr1 Website: https://oracle-base.com Blog: https://oracle-base.com/blog Twitter: https://twitter.com/oraclebase Cameo by Bertrand Drouvot : Blog: https://bdrouvot.wordpress.com/ Twitter : https://twitter.com/BertrandDrouvot Cameo appearances are for fun, not an endorsement of the content of this video. All trademarks, product names and logos are the property of their respective owners.
Views: 1823 ORACLE-BASE.com
Oracle Pseudo Column, Virtual Column , Invisible Column and Unused Column
 
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More Details at, Pseudo Column @ https://www.youtube.com/edit?o=U&video_id=GIGmZwShGh4 Virtual Column @ https://www.youtube.com/edit?o=U&video_id=qUALFDzLDJw Invisible Column @ https://www.youtube.com/edit?o=U&video_id=nz48CdgDCt4 Unused Column @ https://www.youtube.com/edit?o=U&video_id=GWo4VcNZo6Y
Views: 212 Siva Academy
BITMAP  and  BITMAP JOIN INDEX IN ORACLE explained
 
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The video explains BITMAP and BITMAP JOIN INDEX IN ORACLE and when you should create them on a column. BITMAP INDEXES should be dealt with carefully as they can lead to serious performance issues if the table is updated by multiple processes in parallel. Indexing Basics :https://www.youtube.com/watch?v=0X9bbtwTnuE&t=1095s Star and snowflake Schema :https://www.youtube.com/watch?v=Qq4yhhAk9fc&t=17s
Views: 5206 Tech Coach
SQL Server training and interview question:-What is index and how does it make your search faster ?.
 
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For more such videos visit http://www.questpond.com For more such videos subscribe https://www.youtube.com/questpondvideos?sub_confirmation=1 See our other Step by Step video series below :- Learn Angular tutorial for beginners https://tinyurl.com/ycd9j895 Learn MVC Core step by step :- http://tinyurl.com/y9jt3wkv Learn MSBI Step by Step in 32 hours:- https://goo.gl/TTpFZN Learn Xamarin Mobile Programming Step by Step :- https://goo.gl/WDVFuy Learn Design Pattern Step by Step in 8 hours:- https://goo.gl/eJdn0m Learn C# Step by Step in 100 hours :- https://goo.gl/FNlqn3 Learn Data structures & algorithm in 8 hours :-https://tinyurl.com/ybx29c5s Learn SQL Server Step by Step in 16 hours:- http://tinyurl.com/ja4zmwu Learn Javascript in 2 hours :- http://tinyurl.com/zkljbdl Learn SharePoint Step by Step in 8 hours:- https://goo.gl/XQKHeP Learn TypeScript in 45 Minutes :- https://goo.gl/oRkawI Learn webpack in 50 minutes:- https://goo.gl/ab7VJi Learn Visual Studio code in 10 steps for beginners:- https://tinyurl.com/lwgv8r8 Learn Tableau step by step :- https://tinyurl.com/kh6ojyo Preparing for C# / .NET interviews start here http://www.youtube.com/watch?v=gaDn-sVLj8Q In this SQL Server training video we will understand what are indexes and how they make your search faster. We also run through the fundamentals of B-tree or balanced tree structure. Its also one of those favourite SQL Server interview questions which is asked in SQL Server interviews. We are also distributing a 100 page Ebook "Sql Server Interview Question and Answers". If you want this ebook please share this video in your facebook/twitter/linkedin account and email us on [email protected] with the shared link and we will email you the PDF.
Views: 240563 Questpond
Collections in Oracle PLSQL
 
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Complete Oracle PL/SQL Tutorial for Beginners Playlist here https://www.youtube.com/playlist?list=PLI5t0u6ye3FE_9SZcS0cQZDU2qn0uB1Oi ************************************************** Composite DataType - Collections in Oracle PL SQL 1. Difference Between Records and Collections 2. Types of Collections in Oracle 3. VARRAYS 4. Nested Table 3. Associative Arrays / Index BY Tables 4. Multi Dimensional Arrays Using Collections and Records
Views: 19303 yrrhelp
Oracle Database 12c demos: In-Memory Column Store Architecture Overview
 
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The demonstration provides an overview of the architecture of the In-Memory Column Store feature introduced in Oracle Database 12c Release 1 patchset 1.
Clustered and nonclustered indexes in sql server   Part 36
 
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In this video we will learn about 1. Different types of indexes in sql server 2. What are clustered indexes 3. What are NonClustered indexes 4. Difference between clustered and non clustered indexes Text version of the video http://csharp-video-tutorials.blogspot.co.uk/2012/09/clustered-and-non-clustered-indexes.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-36-clustered-nonclustered-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 483350 kudvenkat
Oracle Database Indexes: Myths, Tips and Tricks
 
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In this tutorial, OCM John Watson will - via demonstrations - debunk these myths: Myth #1: Oracle Database does not index NULL Myth #2: A search that includes wildcards can't use an index if the wildcard precedes the string. Myth #3: Oracle will not use a function-based index unless the FBI is coded in the predicate. Myth #4: Indexes always help. The more indexes the better. See http://skillbuilders.com/free-oracle-tutorials for gigabytes of free Oracle video tutorials.
Views: 16322 SkillBuilders
Function Based Indexes in Oracle
 
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How to use Function Based Indexes For Full Course Experience Please Go To http://mentorsnet.org/course_preview?course_id=6 Full Course Experience Includes 1. Access to course videos and exercises 2. View & manage your progress/pace 3. In-class projects and code reviews 4. Personal guidance from your Mentors
Views: 9709 Oresoft LWC
SQL Server 33 - Indexes
 
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Indexes allow us to tell the database that certain columns are columns we want to retrieve commonly. This allows the database to optimize retrieval. Additionally, when we get into the SELECT statement, we will often have to join data from multiple tables. When we correctly add indexes to our tables, we can improve the speed of our SELECT and also our joins. There are two types of Index. One is called clustered and the other is called non-clustered. Clustered indexes determine the actual order of the table. By default this is going to be the primary key column. So when you label a column as PRIMARY KEY, you are also going to be creating an INDEX that is a clustered index. A clustered index is kind of like a telephone book, where the data is right there when you look up a phone number. This means that if you are just making a small database that is only going to store a few things, you may be fine. But more likely than not you are going to want to add additional indexes. When you add a new index, you create a non-clustered index. These things do not actually determine the order of the rows in the table. A way of how you can think of how these work is like an index in the back of a book. The index of the book does not actually contain the data, it just tells you where to find it. What columns do you index? You are going to want every primary key to be indexed. What about foreign keys, are they indexed by default? No, they are not. Of all columns, you are probably going to want to index the foreign keys the most because they are used in joins. Lastly, you will likely want to index columns that you are going to use on a regular basis. You can also make composite indexes just like you can make composite keys. You would want to do this when you are going to constantly being using those columns together. There is a lot to learn on multicolumn indexes. We may explore this concept in more detail and see how SQL Server uses them in a future video, but as of right now it's probably more important that we get a general understanding of all things SQL Server before we deep dive on something like that. In the upcoming videos I'll be teaching you how to create indexes. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 11356 Caleb Curry
Oracle tutorial : What is Virtual column in Oracle PL SQL
 
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This video will show you " Oracle tutorial: What is Virtual column in Oracle PL SQL " sql calculated field computed column oracle-11g-new-feature-virtual-column Oracle tutorial : What is Virtual column in oracle Syntax : column_name [datatype] [GENERATED ALWAYS] AS [expression] [VIRTUAL] 1)The values of the virtual column are not stored in the database. 2)You can not update the values of virtual column. 3)when you try to modify it will give oracle error. 4)These are read only values. 5)Virtual columns used in the WHERE clause of UPDATE and DELETE statement 6)Constraints can be created on them. #techquerypond https://techquerypond.wordpress.com https://twitter.com/techquerypond
Views: 1475 Tech Query Pond
Oracle Database 12c demos: In-Memory Column Store Columns
 
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The demonstration illustrates how columns are handled by in-memory objects in the IM column store.
01 Overview of table Partition in oracle
 
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Partitioning enhances the performance, manageability, and availability of a wide variety of applications and helps reduce the total cost of ownership for storing large amounts of data. Partitioning allows tables, indexes, and index-organized tables to be subdivided into smaller pieces, enabling these database objects to be managed and accessed at a finer level of granularity. Oracle provides a rich variety of partitioning strategies and extensions to address every business requirement. Moreover, since it is entirely transparent, partitioning can be applied to almost any application without the need for potentially expensive and time consuming application changes. Partitioning allows a table, index, or index-organized table to be subdivided into smaller pieces, where each piece of such a database object is called a partition. Each partition has its own name, and may optionally have its own storage characteristics. From the perspective of a database administrator, a partitioned object has multiple pieces that can be managed either collectively or individually. This gives the administrator considerable flexibility in managing partitioned objects. However, from the perspective of the application, a partitioned table is identical to a non-partitioned table; no modifications are necessary when accessing a partitioned table using SQL queries and DML statements. Partitioning Key ======================== Each row in a partitioned table is unambiguously assigned to a single partition. The partitioning key is comprised of one or more columns that determine the partition where each row will be stored. Oracle automatically directs insert, update, and delete operations to the appropriate partition through the use of the partitioning key. When to Partition a Table ========================== Here are some suggestions for when to partition a table: Tables greater than 2 GB should always be considered as candidates for partitioning. Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month's data is updatable and the other 11 months are read only. When the contents of a table need to be distributed across different types of storage devices. When to Partition an Index ============================= Here are some suggestions for when to consider partitioning an index: Avoid rebuilding the entire index when data is removed. Perform maintenance on parts of the data without invalidating the entire index. Reduce the impact of index skew caused by an index on a column with a monotonically increasing value. Partitioned Index-Organized Tables =================================== Partitioned index-organized tables are very useful for providing improved performance, manageability, and availability for index-organized tables. For partitioning an index-organized table: ============================================ Partition columns must be a subset of the primary key columns Secondary indexes can be partitioned (both locally and globally) OVERFLOW data segments are always equi-partitioned with the table partitions See Also: Oracle Database Concepts for more information about index-organized tables System Partitioning System partitioning enables application-controlled partitioning without having the database controlling the data placement. The database simply provides the ability to break down a table into partitions without knowing what the individual partitions are going to be used for. All aspects of partitioning have to be controlled by the application. For example, an insertion into a system partitioned table without the explicit specification of a partition will fail. System partitioning provides the well-known benefits of partitioning (scalability, availability, and manageability), but the partitioning and actual data placement are controlled by the application. See Also: Oracle Database Data Cartridge Developer's Guide for more information about system partitioning Partitioning for Information Lifecycle Management Information Lifecycle Management (ILM) is concerned with managing data during its lifetime. Partitioning plays a key role in ILM because it enables groups of data (that is, partitions) to be distributed across different types of storage devices and managed individually.
Views: 7312 Md Arshad
mysql tutorial for beginners (6/8) : Indexes
 
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mysql tutorial for beginners (6/8) : Indexes As things stand, the table students works and can be searched without problem by MySQL—until it grows to more than a couple of hundred rows, At that point, database accesses will get slower and slower with every new row added, because MySQL has to search through every row whenever a query is issued. This is like searching through every book in a library whenever you need to look something up. Of course, you don’t have to search libraries that way, because they have either a card index system or, most likely, a database of their own. The way to achieve fast searches is to add an index, either when creating a table or at any time afterward. But the decision is not so simple. For example, there are different index types such as a regular INDEX, PRIMARY KEY, and FULLTEXT. Also, you must decide which columns require an index, a judgment that requires you to predict whether you will be searching any of the data in that column. And even when you’ve decided that, you still have the option of reducing index size by limiting the amount of each column to be indexed. If we imagine the searches that may be made on the students table, it becomes apparent that all of the columns may need to be searched. Anyway, go ahead and add an index to each of the columns, using the commands: ALTER TABLE students ADD INDEX(name(3)); An alternative to using ALTER TABLE to add an index is to use the CREATE INDEX command. They are equivalent, except that CREATE INDEX cannot be used for creating a PRIMARY KEY CREATE INDEX surname ON students (surname(5)); DESCRIBE students; These commands create indexes on both the name and surname columns, limiting name index to only the first 3 characters, and surname index to the first 5 characters. For instance, when MySQL indexes the following name: SAFAA It will actually store in the index only the first 3 characters: SAF This is done to minimize the size of the index, and to optimize database access speed. DESCRIBE command shows the key MUL for each column. This key means that multiple occurrences of a value may occur within that column, which is exactly what we want, as name or surname may appear many times. You don’t have to wait, until after creating a table to add indexes. In fact, doing so can be time-consuming, as adding an index to a large table can take a very long time. Therefore, let’s look at a command that creates the table students with indexes already in place. CREATE TABLE students ( Id_studnet SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, name VARCHAR(10) NOT NULL, surname VARCHAR(20) NOT NULL, email VARCHAR(30) NOT NULL, INDEX(name(3)), INDEX(surname(5)), ,PRIMARY KEY(id_studnet),UNIQUE(email)); Another important index, PK, its single unique key for each student to enable instant accessing of a row. The importance of having a key with a unique value for each row will come up when we start to combine data from different tables. You can add PK, while you create the table at the first time, or later by issuing the following command: ALTER TABLE students ADD PRIMARY KEY(id_student); The last important index, FULLTEXT index Unlike a regular index, MySQL’s FULLTEXT allows super-fast searches of entire columns of text. It stores every word in every data string in a special index that you can search using “natural language,” in a similar manner to using a search engine. It’s not strictly true that MySQL stores all the words in a FULLTEXT index, because it has a built-in list of more than 500 words that it chooses to ignore because they are so common that they aren’t very helpful for searching anyway. This list, called stopwords, includes the, as, is, of, and so on. The list helps MySQL run much more quickly when performing a FULLTEXT search and keeps database sizes down. FULLTEXT indexes can be created for CHAR, VARCHAR, and TEXT columns only. A FULLTEXT index definition can be given in the CREATE TABLE statement when a table is created, or added later using ALTER TABLE (or CREATE INDEX). Adding a FULLTEXT index to the table students for the columns name and surname ALTER TABLE classics ADD FULLTEXT(name,surname); this index is in addition to the ones already created and does not affect them You can now perform FULLTEXT searches across this pair of columns. If you find that MySQL is running slower than you think it should be when accessing your database, the problem is usually related to your indexes. Either you don’t have an index where you need one, or the indexes are not optimally designed. Tweaking a table’s indexes will often solve such a problem. In the next tutorial, we will learn about, using FOREIGN KEY Constraints and how to join tables together. Subscribe for more: ---------------------------------------------------------------------------- https://www.youtube.com/subscription_center?add_user=saf3al2a SWE.Safaa Al-Hayali - saf3al2a
Views: 29285 Safaa Al-Hayali
SQL with Oracle 10g XE - Using ALTER TABLE to Modify Table Columns
 
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In this video I use the ALTER TABLE command to modify an existing field column. The command will allow you to change the data types, whether the field can be null, or even the primary key. When using the ALTER TABLE command you would use the keyword MODIFY to make changes to an existing column. Be careful when changing a data type of the null field as existing data may cause an error if not in compliance with the new change. The code I used to alter the Books table is : ALTER TABLE BOOKS MODIFY ISBN_10 VARCHAR(13); This video is part of a series of videos with the purpose of learning the SQL language. For more information visit Lecture Snippets at http://lecturesnippets.com.
Views: 16098 Lecture Snippets
Columns index in Hibernate
 
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In this video you will learn how to define Columns index in Hibernate using a demo project. Below is the GitHub link to download source: https://github.com/kishanjavatrainer/ColumnIndexInHibernate.git
Views: 612 KK JavaTutorials
Oracle SQL Tutorial 13 - How to Add Column Constraints (Attributes)
 
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So far, we have this table declaration: CREATE TABLE users( user_id NUMBER, username VARCHAR(50 CHAR) first_name VARCHAR2(50 CHAR), last_name VARCHAR2(50 CHAR) ) We can run this command see that it works. As we are learning though, we are going to want to be able to recreate our table with different settings and such, but if you try to run this command, it will complain that the table already exists. So we first need to delete this table before we start editing settings. When we get more experienced, we will learn about ways to edit the structure of a table that already exists. To fix this, we can get rid of the table using the DROP TABLE command: DROP TABLE users You can run this every time if you need to practice by adding a semicolon after it. This is how you can tell Oracle that you are putting in another command after it. This is known as a delimiter. When you run the script, it is going to run both commands. Now we can go through and reconsider our table structure. This is fine for starting out because we don't have any important data in our database, but once your database is in production you are not going to want to just drop tables. In the last video we discussed different constraints that you can apply to columns in a database table, but how do you actually apply these when you are creating a table? The first way you define constraints is to put them right after the column in your CREATE TABLE statement. CREATE TABLE users( username VARCHAR2(50 CHAR) NOT NULL ) When we define constraints this way, we usually say we are adding column attributes. If you have two constraints you want to add, you just put one after the other with spaces in between. There is no particular order that is required. CREATE TABLE users( username VARCHAR2(50 CHAR) NOT NULL UNIQUE ) In this situation we have already given the column the NOT NULL and UNIQUE attributes, so we should consider making this a primary key: CREATE TABLE users( username VARCHAR2(50 CHAR) PRIMARY KEY ) As you can see, adding column attributes is super easy. We can add a default like this: CREATE TABLE users( username VARCHAR2(50 CHAR) PRIMARY KEY, account_balance NUMBER DEFAULT 0 ) Note that now we need the comma after the first row. There are a few constraints we did not talk go through an example, specifically foreign keys and check constraints. We will be adding these constraints to our database in future videos. In the mean time, I have a thought for you… Many people prefer to name their column constraints. That way, we can refer to certain constraints by name. For example, we might have a primary key constraint that could be named users_pk. The way we are creating these constraints does not allow for this feature, so in the next video we are going to be discussing different ways to create constraints. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 22556 Caleb Curry
Get Table Names with Column Names and Data Types in SQL Server - SQL Server Tutorial
 
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In this video ,we will generate the script that will return us all the table names with column names and data type of those columns. We often need this information. Let's say we are going to prepare mapping document for load the data from Source Database to Destination database. We can get the list of all tables with column names and data types from Source Database and Destination Database and then paste in Excel and map the required input columns to output columns for ETL Process. Blog link with scripts used in video http://sqlage.blogspot.com/2015/02/get-all-tables-with-column-names-and.html
Views: 49570 TechBrothersIT
How can I speed up a query if an index cannot help?
 
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blog: connor-mcdonald.com Highlights from the April DBA Office Hours session. Office Hours is 100% free Q&A sessions held every month by Oracle experts to help you succeed with the Oracle suite of technologies. Music: Smells Like Summer - Del (Vlog Music No Copyrighted) Video Link: https://youtu.be/IrkMsqcOjGU
Views: 1320 Connor McDonald
How to create Virtual Columns in Oracle Database
 
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How to create Virtual Columns in Oracle Database 12c When queried, virtual columns appear to be normal table columns, but their values are derived rather than being stored on disc. The syntax for defining a virtual column is listed below. column_name [datatype] [GENERATED ALWAYS] AS (expression) [VIRTUAL] If the datatype is omitted, it is determined based on the result of the expression. The GENERATED ALWAYS and VIRTUAL keywords are provided for clarity only. The script below creates and populates an employees table with two levels of commission. It includes two virtual columns to display the commission-based salary. The first uses the most abbreviated syntax while the second uses the most verbose form. CREATE TABLE employees ( id NUMBER, first_name VARCHAR2(10), last_name VARCHAR2(10), salary NUMBER(9,2), comm1 NUMBER(3), comm2 NUMBER(3), salary1 AS (ROUND(salary*(1+comm1/100),2)), salary2 NUMBER GENERATED ALWAYS AS (ROUND(salary*(1+comm2/100),2)) VIRTUAL, CONSTRAINT employees_pk PRIMARY KEY (id) ); INSERT INTO employees (id, first_name, last_name, salary, comm1, comm2) VALUES (1, 'JOHN', 'DOE', 100, 5, 10); INSERT INTO employees (id, first_name, last_name, salary, comm1, comm2) VALUES (2, 'JAYNE', 'DOE', 200, 10, 20); COMMIT; Querying the table shows the inserted data plus the derived commission-based salaries. SELECT * FROM employees; ID FIRST_NAME LAST_NAME SALARY COMM1 COMM2 SALARY1 SALARY2 ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- 1 JOHN DOE 100 5 10 105 110 2 JAYNE DOE 200 10 20 220 240 2 rows selected. SQL The expression used to generate the virtual column is listed in the DATA_DEFAULT column of the [DBA|ALL|USER]_TAB_COLUMNS views. COLUMN data_default FORMAT A50 SELECT column_name, data_default FROM user_tab_columns WHERE table_name = 'EMPLOYEES'; COLUMN_NAME DATA_DEFAULT ------------------------------ -------------------------------------------------- ID FIRST_NAME LAST_NAME SALARY COMM1 COMM2 SALARY1 ROUND("SALARY"*(1+"COMM1"/100),2) SALARY2 ROUND("SALARY"*(1+"COMM2"/100),2) 8 rows selected. SQL Notes and restrictions on virtual columns include: 1)Indexes defined against virtual columns are equivalent to function-based indexes. 2)Virtual columns can be referenced in the WHERE clause of updates and deletes, but they cannot be manipulated by DML. 3)Tables containing virtual columns can still be eligible for result caching. 4)Functions in expressions must be deterministic at the time of table creation, but can subsequently be recompiled and made non-deterministic without invalidating the virtual column. In such cases the following steps must be taken after the function is recompiled: a)Constraint on the virtual column must be disabled and re-enabled. b)Indexes on the virtual column must be rebuilt. c)Materialized views that access the virtual column must be fully refreshed. d)The result cache must be flushed if cached queries have accessed the virtual column. e)Table statistics must be regathered. 5)Virtual columns are not supported for index-organized, external, object, cluster, or temporary tables. 6)The expression used in the virtual column definition has the following restrictions: a.It cannot refer to another virtual column by name. b.It can only refer to columns defined in the same table. c.If it refers to a deterministic user-defined function, it cannot be used as a partitioning key column. e.The output of the expression must be a scalar value. It cannot return an Oracle supplied datatype, a user-defined type, or LOB or LONG RAW.
Views: 518 OracleDBA
002 Virtual Columns
 
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Views: 574 Kartik Mundhra
Data Warehouse 9 ColumnStore Indexes
 
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02:27 Row storage 05:40 ColumnStore Storage 12:32 ColumnStore Batch Mode and CPU caches 18:11 Demo ColumnStore Index Segment Elimination 31:28 Clustered Columstore Index Delta Store SQL Server 2012 Non-Clustered Columnstore Index, SQL Server 2014 Clustered Columnstore Index Brain Mitchell: What's New for Columnstore Indexes and Batch Mode Processing http://channel9.msdn.com/Events/TechEd/NorthAmerica/2013/DBI-B322#fbid=GMKVwjUCe2g
Views: 7915 Garrett Edmondson
skip_unusable_indexes is NOT skipping unusable indexes!
 
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blog: connor-mcdonald.com Highlights from the April DBA Office Hours session. Office Hours is 100% free Q&A sessions held every month by Oracle experts to help you succeed with the Oracle suite of technologies. Music: Smells Like Summer - Del (Vlog Music No Copyrighted) Video Link: https://youtu.be/IrkMsqcOjGU
Views: 319 Connor McDonald
Indexes in sql server   Part 35
 
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In this video we will learn about What are indexes Why do we use indexes Advantages of indexes These concepts are applicable to sql server 2000, 2005 and 2008 Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/indexes-in-sql-server-part-35.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-35-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 397162 kudvenkat
CREATING INDEX ON COMPUTED COLUMN IN SQL (URDU / HINDI)
 
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SUBSCRIBE FOR MORE AND PRESS BELL ICON TO GET LATEST VIDEO UPDATES...
Views: 169 Learning Never Ends
Oracle Database11g tutorials 8 || SQL DISTINCT with multiple columns |SQL Distinct with Two columns
 
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This SQL tutorial and Oracle database 11g tutorial for beginners will show how to use SQL DISTINCT keyword with SQL Select clause. This Video is in the continuation of previous video on SQL distinct with one column. In this video we will see How to use SQL distinct with multiple columns and SQL distinct with two columns Tool used in this tutorial is SQL developer. This tutorial series is part of SQL expert exam certification training. If you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts Email [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. in.linkedin.com/in/mannbhardwaj/ Thanks for linking, commenting, sharing and watching more of our videos This is Manish From The Code makers
Views: 100880 Manish Sharma
Oracle SQL Tutorial 14 - Column-Level and Table-Level Constraints
 
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In the previous video we talked about adding constraints at the column-level. We made it nice and simple by only requiring a few keywords, but the problem we were having is that we could not assign a name to the constraint, which many people like to do so we can reference easily if we need to at a later time. To do this, it requires a little bit more typing, but it will give us extra flexibility and many consider it to be the higher quality approach to adding constraints. Let's go though a simple example. Let's say we have a users table with a user_id column that we want to make a primary key. We will create the table like this: CREATE TABLE( user_ id NUMBER PRIMARY KEY ) Instead of adding the PRIMARY KEY keywords after the data type, we add: CONSTRAINT user_pk PRIMARY KEY Now, we have assigned the name user_pk to this constraint. You can do the same with other constraints, such as UNIQUE. The syntax would be CONSTRAINT username_un UNIQUE. The other way to create constraints requires to put all of our constraints at the bottom of our table creation rather than inline with the column. This type of constraint is known as a table-level constraints. To make a column a primary key using table-level constraints, we add it to the CREATE TABLE command as if it is another row and use the CONSTRAINT keyword to tell Oracle that what is coming is a constraint, not a column in our table. CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR), CONSTRAINT username_un UNIQUE (username), CONSTRAINT users_pk PRIMARY KEY (user_id) ) The primary differences here is that you have to put the column you are talking about in parenthesis after the PRIMARY KEY keyword. That's because it's at the end of the table and you need a way to tell it what column you are talking about. The option of putting it at the end of the table has the added benefit in this situation because if we needed to have a primary key that is the combination of multiple columns, we can do that by just adding the other column in the PRIMARY KEY parenthesis right after a comma. In summary, there are three ways to make constraints. The first is at the column level, unnamed. The second is at the column level, named. The third is at the table level, also named. In the next video we are going to create a named constraint in Oracle SQL Developer, so stay tuned and be sure to subscribe! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 16452 Caleb Curry
【VDEDU】Unusable indexes use
 
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Unusable indexes in Oracle, DML statements are not use the index to its maintenance, at the same time the optimizer will not use the index. Unusable indexes no segment exists. Unavailable index index becomes available methods are: 1. Place the index can not be truncate operation corresponding table; 2.rebuild index; In addition, the query optimizer can use conversion method expand table so that the SQL statement has encountered unusable index partition table to generate better execution plans.
Views: 65 崔旭
SQL tutorial 23: Rename and Modify Column Using Alter Table By Manish Sharma (RebellionRider)
 
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How to Rename a column of a table using alter table and How to modify a column of a table using alter table Modify means How to change datatype of a column and how to change size/width of a column Web Article link http://bit.ly/sql-tutorial23 Tutorial 21 How to rename a table : http://bit.ly/sql-tutorial-21 Tutorial 22 How to add/ delete column: http://bit.ly/sql-tutorial-22 YouTube Video on How to create database http://bit.ly/create-database-using-DBCA Tool used in this tutorial is SQL Developer. This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts E-Mail [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. http://in.linkedin.com/in/mannbhardwaj/ Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com
Views: 46343 Manish Sharma
Oracle Invisible Column
 
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Oracle 12c new feature - Invisible column https://easy-learning-tech.blogspot.com/2018/05/invisible-column-from-oracle-12c.html oracle 12c new features for developers
Views: 157 Siva Academy
How Does the Phyiscal Location of Rows Affect Indexes?: Finding All the Red Sweets Part 2
 
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In part one of the red candy series, Chris compared the efficiency of using a index range scan and full table scan to access data. He found that a full table scan was more efficient when fetching more rows than there are table blocks. This analysis made a big assumption however. It worked on the presumption that there was no correlation between the order of candies in the document and which the bags they were in. In this episode tests this assumption. Chris looks at how the physical order of rows in a table can affect the efficiency of indexes on it. He discusses how Oracle tracks this via the clustering factor. ============================ 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: 3369 The Magic of SQL
Oracle Tutorial - How to add virtual column in oracle 11g
 
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Hello friends in this video i'm going to demonstrate you how to add virtual column in ORACLE 11g step by step. Oracle 11g supports virtual columns which are derived from the other columns in the table. You can use the virtual columns in your queries, you can index them, you can collect the statistics, etc. There are few restrictions on the virtual columns. You cannot write/insert the data into virtual columns. There is no support for index_organized, external, object, cluster, temporary tables.
Views: 1411 OCP Technology
How Many Indexes Are Too Many?: Finding All The Red Sweets Part 5
 
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Every index you add to a table increases its storage requirements and DML overheads. So it's a good idea to create as few as possible. When you have two or more indexes using the same columns, you may be able to get away with just one. But how do you decide which to keep? This video discusses how to analyze your queries so you can cut the number of indexes you create. ============================ 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: 2365 The Magic of SQL
How to use Pivot and Unpivot? (how to change rows to column and column to rows)
 
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This is a video tutorial on using pivot and unpivot operators to change rows to column and columns to rows when needed, the video also demonstrates a way to change from rows to column without using the pivot operator which can be helpful if you are using and older version of oracle or some other database without the feature of pivot and unpivot. Both the operators are explained with an example for better understanding
Views: 7915 Kishan Mashru
How to create an index in SQL developer
 
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In this video you learn how to create an Index in Oracle SQL developer.
Views: 253 F&F Academy