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Database Articles
Page 324 of 547
Difference between oracle golden gate and oracle active guard in the oracle
Oracle golden gate and oracle active data guard is the data replication technologies. They both are used for data replication but with different strategy. As per the oracle docs −Oracle Active Data Guard provides the best data protection and availability for Oracle Database in the simplest most economical manner by maintaining an exact physical replica of the production copy at a remote location that is open read-only while replication is active. GoldenGate is an advanced logical replication product that supports multi-master replication, hub and spoke deployment and data transformation, providing customers very flexible options to address the complete range of replication requirements. ...
Read MoreDifference between logical and physical standby database in the oracle
Logical standby and physical standby database in two different types of standby database. In case of any failure of primary database Oracle transfer data from primary database to the standby database. This approach helps us to recover data from standby database in case of any failure.Logical standby database is not the exact copy of the primary database. Logical standby uses LogMiner techniques to transform the archived redo logs into native DML statements (insert, update, delete). This DML is transported and applied to the standby database.Primary standby database is the exact copy of primary database so it helps to minimize the ...
Read MoreDifference between Inner and Outer join in SQL
In Relational database tables are associated with each other and we used foreign key to maintain relationships between tables. We used join clause to retrieve data from associated tables. The join condition indicates how column in each table are matched against each other. There are two types of joins clause in SQL Inner join Outer joinOuter join is again divided into parts −LEFT OUTER JOIN - It will return all data of the left table and matched records in both table RIGHT OUTER JOIN - it will return all the data of the right table and matched records in ...
Read MoreDifference between ETL and ELT in SQL Server
ETL stands for Extract, Transform and Load. ETL tool is used to extract data from the source RDBMS database and transform extracted data such as applying business logic and calculation, etc. and then load data into the target data warehouse. In ETL tool, transformation of the data performed at the ETL server. It is used for low amount data.ELT stands for Extract, Load and Transform. ELT tool is also used to extract data from source database and then load data into target database without transformation. In ELT, transformation of data is performed at the target database. In general, in an ...
Read MoreHow To Change The MySQL Data Directory to Another Location on Ubuntu 16.04
In this article, we will learn how to change the MySQL Data Directory or relocate the MySQL Database data to the new location, this situation may be used when the database is growing very fast, or for some security reasons we want to move the data directory to the new location.PrerequisitesAn Ubuntu machine with a non-root user with Sudo permission.MySQL installed and working.A new volume or location where we want to move the database data location, the new location will be /mnt/data_vol/MySQL as the data_vol is the new volume attached to the machine or server.Changing the MySQL Data Folder LocationBefore ...
Read MoreHow to Setup SSL for MySQL Server and Client on Linux
In this tutorial, I will be explaining about – how to set up a secure connection to MySQL server using an SSH connection for encryption so that data in the database will be in safe and which is impossible for hackers to steal the data. SSL is used to verify the means of SSL certificates which can protect against phishing attacks. This will also show you – how to enable SSL on MySQL server also.Enabling SSL SupportConnect to the MySQL server and check that SSL status of the MySQL server# mysql -u root -p mysql> show variables like '%ssl%'; Output: ...
Read MoreDatabase Wars: MSSQL Server, Oracle PL/SQL and MySQL
With so many databases in the market, the mind wars have begun and it is the right time to understand the difference and importance of top 3 relational databases in the market – Microsoft SQL Server, Oracle PL/SQL, and MySQL. The relational database management systems have currently become the backbone of the industry and with so many options available, it is difficult to figure out which one to choose.The relational database management systems was introduced in 1980’s. This article is focussing on exploring the history and features of three popular RDBMS in the industry: Microsoft SQL Server, Oracle, and MySQL. ...
Read MoreUsing LIKE clause twice in a MySQL query
Let us first create a table −mysql> create table DemoTable2009 ( Name varchar(20) ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2009 values('John Doe'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable2009 values('Adam Smith'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable2009 values('John Smith'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable2009 values('David Miller'); Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −mysql> select * from DemoTable2009;This will produce the following output ...
Read MoreMySQL query to insert multiple records quickly
To insert multiple records quickly, use a single INSERT and follow the below syntax −insert into yourTableName values(yourValue1, yourValue2, ...N), (yourValue1, yourValue2, ...N).....N;To understand the above syntax, let us create a table −mysql> create table DemoTable2007 ( Amount1 int, Amount2 int, Amount3 int ); Query OK, 0 rows affected (1.36 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2007 values(450, 600, 700), (1000, 200, 3000), (800, 900, 1200), (1300, 1500, 2000), (40000, 50000, 6700); Query OK, 5 rows affected (0.11 sec) Records: 5 Duplicates: 0 Warnings: 0Display all records from the table ...
Read MoreFetch a specific record from a column with string values (string, numbers and special characters) in MySQL
For this, you can use ORDER BY CAST(). Let us see an example −mysql> create table DemoTable2006 ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserCode varchar(20) ); Query OK, 0 rows affected (1.14 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2006(UserCode) values('John_12'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable2006(UserCode) values('John_34'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable2006(UserCode) values('John_56'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2006(UserCode) values('Chris_101'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable2006(UserCode) values('Chris_103'); Query ...
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