使用在postgresql.org下载的x86_64二进制版的postgres 9.0.3安装包,解压到了/opt/pgsql。使用initdb命令初始化数据库后向往
使用在postgresql.org下载的x86_64二进制版的postgres 9.0.3安装包,解压到了/opt/pgsql。使用initdb命令初始化数据库后向往常一样使用psql命令登陆数据库,,提示找不到termcap等一些动态库,把/opt/pgsql/lib目录加入LD_LIBRARY_PATH环境变量就好了。
再次使用psql登陆数据库,却提示如下错误:
google查找后说是缺少termcap库,但是在/opt/pgsql/lib目录下是有这个库的:libtermcap.so.2,我给它做了个软链接libtermcap.so后再次运行psql命令错误依旧。后来安装了系统自带的compat-libtermcap-2.0.8-49.el6.x86_64软件包后就可以正常运行psql命令登陆数据库了。发现termcap包在/etc目录下生成了一个termcap数据库文件。我把/etc/termcap文件备份后删除compat-libtermcap软件包,再把termcap文件拷贝回/etc目录再次运行psql命令也能正常登陆postgresql数据库。看来我只需要把termcap文件留个备份就好了,以后再次使用官方的二进包安装时将其放到/etc目录就行了。
(注:使用rpm包安装的不需要termcap数据文件,看了下psql的库依赖都没有使用到libtermcap.so。不知道官方的二进制包为什么需要这个库。现在大部份软件都是使用的ncurses了。)

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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