Features of MySQL
1. Excellent performance, stable service, and rarely abnormal downtime;
2. Open source code has no version restrictions, autonomy and low use cost;
3. It has a long history, the community and users are very active, and they seek help in time when they encounter problems;
4. The software is small in size, simple to install and easy to maintain, and low in maintenance cost; brand word-of-mouth effect;
5. Support a variety of OS, provide a variety of API interfaces, support a variety of development languages, and support the popular PHP and Java
Disadvantages of MySQL
1. The biggest disadvantage of MySQL is that its security system is mainly complex rather than standard, and it will only change when mysqladmin is called to reread user permissions;
2. Another major approach to MySQL is the lack of a standard RI (Referential Integrity-RI) mechanism, which can be compensated for by a large number of data types.
3. MySQL does not support hot backup;
Oracle features:
1. Compatibility: Oracle products use standard SQL, and have been tested by the U-Architecture Standards Technology Institute (NIST) in the United States, and are compatible with IBM SQL/DS, DB2, INGRES, IDMS/R, etc.
2. Portability: Oracle's products can run on a wide range of hardware and operating system platforms. It can be installed on a variety of large, medium and small computers, and can work under a variety of operating systems.
3. Connectivity: Oracle can be connected to a variety of communication networks and support various protocols.
4. High productivity: Oracle products provide a variety of development tools, which can greatly enable users to carry out further development.
5. Openness: Oracle's good compatibility, portability, connectivity, and high productivity make Oracle RDBMS have good openness.
Disadvantages of Oracle
1. High requirements for hardware;
2. The price is relatively expensive;
3. Management and maintenance are troublesome;
4. The operation is complex and requires high technical content;
The differences between MySQL and Oracle are as follows:
1. Oracle database is an object relational database management system, which is charged; MySQL is an open-source relational database management system that is free;
2. Differences in database security;
3. The difference between the names of objects;
4. Differences in the processing of temporary tables, etc.
MySQL and Oracle are both popular relational database management systems (RDBMS) that are widely used around the world; Most databases work in a similar way, but there are always some differences here and there between MySQL and Oracle. In this article, I will compare Oracle and MySQL and introduce the differences between Oracle and MySQL, hoping to help you.
What is the difference between MySQL and Oracle? The characteristics of the two databases are different, so MySQL is used differently compared to Oracle; The usage of Oracle is different compared to MySQL. Their characteristics are also different. Let's take a look at the differences between MySQL and Oracle.
0. Macroscopically:
1. Oracle is a large database, while Mysql is a small and medium-sized database; Mysql is open source, while Oracle is fee-based and expensive.
2. Oracle supports large concurrency and large visits, and is the best tool for OLTP.
3. There is also a difference in the memory occupied by the installation, the memory occupied after the installation of Mysql is much smaller than the memory occupied by Oracle, and the more Oracle uses it, the more memory it occupies.
1. The difference in essence
Oracle Database is an object relational database management system (ORDBMS). It is often referred to as Oracle RDBMS or Oracle for short, and is a fee-based database.
MySQL is an open-source relational database management system (RDBMS). It is the most used RDBMS in the world and operates as a server, providing multi-user access to multiple databases. It is an open-source, free database.
2. Database security
MySQL uses three parameters to authenticate the user, namely username, password, and location; Oracle uses a number of security features such as usernames, passwords, profiles, local authentication, external authentication, advanced security enhancements, and more.
3. Differences in SQL syntax
Oracle's SQL syntax is very different from MySQL. Oracle offers more flexibility for a programming language called PL/SQL. Oracle's SQL* Plus tool provides more commands than MySQL for generating report outputs and variable definitions.
4. Differences in storage:
In contrast to Oracle, MySQL has no tablespaces, role management, snapshots, synonyms and packages, and automatic storage management.
5. Difference between object names:
While some schema object names are case-insensitive in both Oracle and MySQL, such as columns, stored procedures, indexes, etc. But in some cases, the case sensitivity between the two databases is different.
Oracle is case-insensitive to all object names; Some MySQL object names, such as databases and tables, are case-sensitive (depending on the underlying operating system).
6. Running program and external program support:
Oracle Database supports several programming languages that are written, compiled, and executed from within the database. In addition, in order to transfer data, Oracle Database uses XML.
MySQL does not support the execution of other languages within the system, nor does it support XML.
7. Comparison of character data types between MySQL and Oracle:
There are some differences in the types of characters supported in the two databases. For character types, MySQL has CHAR and VARCHAR, with a maximum length of 65,535 bytes allowed (CHAR can be up to 255 bytes and VARCHAR is 65.535 bytes).
Whereas, Oracle supports four character types, namely CHAR, NCHAR, VARCHAR2, and NVARCHAR2; All four character types need to be at least 1 byte long; The maximum limit for CHAR and NCHAR can be 2000 bytes, and the maximum limit for NVARCHAR2 and VARCHAR2 is 4000 bytes. Extensions may be made in the latest version.
8. Comparison of additional features of MySQL and Oracle:
MySQL databases don't support any features on their servers, such as Audit Vault. Oracle, on the other hand, supports several extensions and programs on its database servers, such as Active Data Guard, Audit Vault, Partitioning, and Data Mining, among others.
9. The difference between temporary tables:
Oracle and MySQL handle temporary tables differently.
In MySQL, temporary tables are database objects that are only visible to the current user's session, and are automatically deleted once the session ends.
The definition of temporary tables in Oracle is slightly different from MySQL in that temporary tables exist once they are created until they are explicitly deleted and are visible to all sessions with the appropriate permissions. However, the data in the temporary table is only visible to the user session in which the data is inserted into the table, and the data may persist for the duration of a transaction or user session.
10. Backup types in MySQL and Oracle:
Oracle provides different types of backup tools, such as cold backup, hot backup, export, import, data pump. Oracle offers the most popular backup utility called Recovery Manager (RMAN). With RMAN, we can automate our backup scheduling and recovery database with very few commands or storage scripts.
MySQL has mysqldump and mysqlhotcopy backup tools. There is no such utility as RMAN in MySQL.
11. Oracle and MySQL database management:
In the database management part, Oracle DBAs are more profitable than MySQL DBAs. Compared to MySQL, Oracle DBA has a lot of scopes available.
12. Database certification:
MySQL certification is easier than Oracle certification.
Unlike Oracle (when set up to use database authentication) and most other databases that only authenticate users with usernames and passwords, MySQL uses additional parameters when authenticating users to location. This location parameter is usually a hostname, IP address, or wildcard.
With this additional parameter, MySQL can further restrict user access to the database to specific hosts or hosts in the domain. In addition, this allows different sets of secrets and permissions to be enforced for users depending on the host making the connection. As a result, the user Scott who logged in from the abc.com may be the same or different from the user Scott who logged in from the xyz.com.
Differences between MySQL and Oracle applications
1. The use of the primary key:
MySQL: When creating a table, as long as the primary key of the table is set to auto increment, you do not need to add records to the primary key when inserting records, and the primary key will automatically grow.
Oracle: There is no auto-growth, the primary key generally uses a sequence, and the next value of the sequence number can be assigned to this field when inserting a record, but the ORM framework only needs the native primary key to generate a policy.
2. Handling of long strings
THE HANDLING OF LONG STRINGS WITH ORACLES ALSO HAS ITS PECULIARITIES. INSERT and UPDATE are maximum operable string lengths less than or equal to 4000 single characters.
IF YOU WANT TO INSERT LONGER STRINGS, CONSIDER USING THE CLOB TYPE FOR THE FIELD, AND BORROWING THE NATIVE DBMS_LOB PACKAGE FROM ORACLE. Before inserting the change record, you must make a non-null and length judgment, and the field values that cannot be empty and the values that exceed the length should be warned and the last operation should be returned.
3. Comparison of fuzzy queries
MySQL: Use field name like%'string%'
Oracle: You can also use the field name like%'string%' but this method can't use indexes, it's not fast, and you can use a string comparison function
isnert (field name, 'string') > 0 will give you more precise results
4. Comparison of empty strings:
MySQL non-empty fields also have empty content, and Oracle defines that non-empty fields are not allowed to have empty content. Use the not null parameter of MySQL to define the Oracle table structure.
When it comes to the data, errors are generated. Therefore, the derivative data is to judge the null character, and if it is a null or null character, it needs to be changed to a blank string.
5. Handling of single quotation marks
In MySQL, you can wrap a string in double quotation marks, and in Oracle, you can only use a single quotation mark to wrap a string, and you must replace it with a single quote before inserting and modifying the string;
Replace all occurrences with one single quotation mark with two single quotation marks