Features of MySQL
1. Excellent performance, stable service, and rare abnormal downtime;
2. Open source code has no version restrictions, autonomy and low cost of use;
3. With a long history, the community and users are very active, and you can seek help in time if you encounter problems;
4. The software is small in size, easy to install and use, easy to maintain, and low maintenance cost; brand reputation effect;
5. Support a variety of OS, provide a variety of API interfaces, support a variety of development languages, very good support for the popular PHP, Java
Disadvantages of MySQL
1. The biggest disadvantage of MySQL is its security system, which is mainly complex rather than standard. In addition, it will only change when calling mysqladmin to re-read user permissions;
2. One of the other main ways of MySQL is the lack of a standard RI (Referential Integrity-RI) mechanism. The lack of RI restrictions (a fixed range restriction on a given field domain) can be resolved through a large number of data types. compensate;
3. MySQL does not support hot backup;
Features of Oracle
1. Compatibility: Oracle products use standard SQL, and have been tested by the National Institute of Standards and Technology (NIST), 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 various large, medium and small computers, and can work under various operating systems.
3. Connectability: Oracle can be connected with various 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 hardware requirements;
2. The price is relatively expensive;
3. Management and maintenance are troublesome;
4. The operation is more complicated and requires high technical content;
The difference between mysql and oracle are:
1. Oracle database is an object-relational database management system, which is charged; MySQL is an open source relational database management system, which is free;
2. The difference in database security;
3. The difference between object names;
4. Differences in the processing methods of temporary tables and so on.
Both MySQL and Oracle are popular relational database management systems (RDBMS) 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. This article will compare Oracle and MySQL for you, and introduce the differences between Oracle and MySQL. I hope it will be helpful to 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; Oracle is used differently compared to MySQL. Their characteristics are also different. Let's take a closer look at the differences between MySQL and Oracle.
1. Essential difference
Oracle Database is an object-relational database management system (ORDBMS). It is often referred to as Oracle RDBMS or simply Oracle, 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 runs 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 users, namely username, password, and location; Oracle uses many security features like username, password, configuration files, local authentication, external authentication, advanced security enhancements, etc.
3. Differences in SQL syntax
Oracle's SQL syntax is very different from MySQL. Oracle provides more flexibility to the programming language known as PL/SQL. Oracle's SQL*Plus tools provide more commands than MySQL for generating report output and variable definitions.
4. The difference in storage:
Compared to Oracle, MySQL does not have tablespaces, role management, snapshots, synonyms and packages, and automatic storage management.
5. The 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 is different between the two databases.
Oracle treats all object names as case-insensitive; whereas some MySQL object names (such as database and table) 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. Also, 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 character types supported in the two databases. For character types, MySQL has CHAR and VARCHAR, with a maximum length allowed of 65,535 bytes (CHAR can be up to 255 bytes, and VARCHAR is 65.535 bytes).
However, Oracle supports four character types, namely CHAR, NCHAR, VARCHAR2, and NVARCHAR2; all four character types need to be at least 1 byte long; CHAR and NCHAR can be a maximum of 2000 bytes, and the maximum limit of NVARCHAR2 and VARCHAR2 is 4000 bytes. May be extended in latest version.
8. Comparison of additional functions between MySQL and Oracle:
MySQL database does not support any features on its server such as Audit Vault. On the other hand, Oracle supports several extensions and programs on its database server such as Active Data Guard, Audit Vault, Partitioning, and Data Mining, etc.
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 session, and these tables are automatically dropped once the session ends.
Temporary tables are defined slightly differently in Oracle than in MySQL, in that once created temporary tables exist until they are explicitly dropped and are visible to all sessions with appropriate privileges. However, data in temporary tables is only visible to the user session that inserted the data into the table, and the data may persist across transactions or user sessions.
10. Backup types in MySQL and Oracle:
Oracle provides different types of backup tools like cold backup, hot backup, export, import, data pump. Oracle provides the most popular backup utility called Recovery Manager (RMAN). Using RMAN, we can automate our backup schedules and restore databases with very few commands or stored scripts.
MySQL has mysqldump and mysqlhotcopy backup tools. There is no utility like RMAN in MySQL.
11. Database management of Oracle and MySQL:
In the database administration part, Oracle DBA is more profitable than MySQL DBA. Compared to MySQL, Oracle DBA has a lot of scope available.
12. Database authentication:
MySQL certification is easier than Oracle certification.
Unlike Oracle (when set to use database authentication) and most other databases that only use username and password to authenticate users, MySQL uses additional parameters when authenticating users to a location. This location parameter is usually a hostname, IP address or wildcard.
Using this additional parameter, MySQL can further restrict a user's access to the database to specific hosts or hosts within the domain. Additionally, this allows a different set of passwords and permissions to be enforced for the user depending on the host making the connection. So user scott logging in from abc.com may or may not be the same as user scott logging in from xyz.com.
Application difference between MySQL and Oracle
1. The use of the primary key:
MySQL: Generally, the automatic growth type is used. When creating a table, as long as the primary key of the table is specified as auto increment, when inserting records, there is no need to add records for the primary key, and the primary key will automatically increase;
Oracle: There is no automatic growth. The primary key generally uses a sequence. When inserting a record, the next value of the sequence number can be paid to this field, but the ORM framework only needs a native primary key generation strategy.
2. Processing of long strings
The processing of long strings ORACLE also has its special place. The maximum operable string length for INSERT and UPDATE is less than or equal to 4000 single characters,
If you want to insert a longer string, please consider using the CLOB type for the field, and the method borrows the DBMS_LOB package that comes with ORACLE. Before inserting and modifying records, it is necessary to make non-null and length judgments. Field values that cannot be empty and values exceeding the length should be warned and return to the last operation.
3. Comparison of fuzzy queries
MySQL: use field name like%'string%'
Oracle: You can also use the field name like%'string%' but this method cannot use the index, the speed is not fast, use the string comparison function
isnert(field name,'string')>0 will get more precise search results
4. Comparison of empty strings:
MySQL's non-empty fields also have empty content, and Oracle does not allow empty content if a non-empty field is defined. Define the Oracle table structure according to MySQL's not null.
An error occurs when importing data. Therefore, the null character is judged when importing data. If it is Null or empty character, it needs to be changed to a string of spaces.
5. Processing of single quotation marks
In MySQL, strings can be wrapped in double quotes, but in Oracle, strings can only be wrapped in single quotes. Single quotes must be replaced before inserting and modifying strings; replace
all occurrences of single quotes with two single quotes
Original link: https://blog.csdn.net/qw1666524914/article/details/119836080