create database Student;create table StuInfo( stuName varchar(8), stuId varchar(12) primary key, stuAge int, stuSex varchar(4));
创建数据库,表格。
alter table stuinfo drop stuSex,add stuSex varchar(4);
修改表格式。其中表格不区分大小写,字段区分大小写。
insert into stuinfo(stuName,stuAge,stuSex,stuId)values("朱豪",22,"男","123456");
添加数据。
select * from stuinfo;
查询数据。
jdbc连接mysql
public static void main(String[] args) { // TODO Auto-generated method stub Connection conn=null; try{ String mysqlStr="com.mysql.jdbc.Driver"; String url="jdbc:mysql://localhost:3306/Student"; String user="root"; String password="mysql"; String selectSql="select * from stuinfo;"; String createSql="create table stuinfo(stuName varchar(8),stuId varchar(8),stuSex varchar(4),stuAge int);"; String insertSql="insert into stuinfo(stuName,stuId,stuSex,stuAge)values(?,?,?,?);"; Class.forName(mysqlStr); conn=DriverManager.getConnection(url,user,password); PreparedStatement ps=conn.prepareStatement(insertSql); ps.setString(1, "呵呵"); ps.setString(2, "12345"); ps.setString(3, "男"); ps.setInt(4, 22); ps.execute(); ResultSet rs=ps.executeQuery(selectSql); if(conn!=null){ System.out.println("连接成功!"); } while(rs.next()){ String tname=rs.getString("stuName"); String tsex=rs.getString("stuSex"); String tid=rs.getString("stuId"); int tage=rs.getInt("stuAge"); //System.out.println(rs.getRow()); System.out.println(tname+"-----"+tsex+"----"+tid+"-----"+tage); } }catch(ClassNotFoundException e){ e.printStackTrace(); }catch(SQLException e){ e.printStackTrace(); } }
别忘记添加jdbc连接的jar文件
mysql装在c盘program files的话,路径如下:
C:/Program Files/MySQL/Connector J 5.1.23
文件名为(不同版本可能略微有所区别):
mysql-connector-java-5.1.23-bin.jar
这里有一份w3cschool上的教程:
点击打开链接

MySQL'sBLOBissuitableforstoringbinarydatawithinarelationaldatabase,whileNoSQLoptionslikeMongoDB,Redis,andCassandraofferflexible,scalablesolutionsforunstructureddata.BLOBissimplerbutcanslowdownperformancewithlargedata;NoSQLprovidesbetterscalabilityand

ToaddauserinMySQL,use:CREATEUSER'username'@'host'IDENTIFIEDBY'password';Here'showtodoitsecurely:1)Choosethehostcarefullytocontrolaccess.2)SetresourcelimitswithoptionslikeMAX_QUERIES_PER_HOUR.3)Usestrong,uniquepasswords.4)EnforceSSL/TLSconnectionswith

ToavoidcommonmistakeswithstringdatatypesinMySQL,understandstringtypenuances,choosetherighttype,andmanageencodingandcollationsettingseffectively.1)UseCHARforfixed-lengthstrings,VARCHARforvariable-length,andTEXT/BLOBforlargerdata.2)Setcorrectcharacters

MySQloffersechar, Varchar, text, Anddenumforstringdata.usecharforfixed-Lengthstrings, VarcharerForvariable-Length, text forlarger text, AndenumforenforcingdataAntegritywithaetofvalues.

Optimizing MySQLBLOB requests can be done through the following strategies: 1. Reduce the frequency of BLOB query, use independent requests or delay loading; 2. Select the appropriate BLOB type (such as TINYBLOB); 3. Separate the BLOB data into separate tables; 4. Compress the BLOB data at the application layer; 5. Index the BLOB metadata. These methods can effectively improve performance by combining monitoring, caching and data sharding in actual applications.

Mastering the method of adding MySQL users is crucial for database administrators and developers because it ensures the security and access control of the database. 1) Create a new user using the CREATEUSER command, 2) Assign permissions through the GRANT command, 3) Use FLUSHPRIVILEGES to ensure permissions take effect, 4) Regularly audit and clean user accounts to maintain performance and security.

ChooseCHARforfixed-lengthdata,VARCHARforvariable-lengthdata,andTEXTforlargetextfields.1)CHARisefficientforconsistent-lengthdatalikecodes.2)VARCHARsuitsvariable-lengthdatalikenames,balancingflexibilityandperformance.3)TEXTisidealforlargetextslikeartic

Best practices for handling string data types and indexes in MySQL include: 1) Selecting the appropriate string type, such as CHAR for fixed length, VARCHAR for variable length, and TEXT for large text; 2) Be cautious in indexing, avoid over-indexing, and create indexes for common queries; 3) Use prefix indexes and full-text indexes to optimize long string searches; 4) Regularly monitor and optimize indexes to keep indexes small and efficient. Through these methods, we can balance read and write performance and improve database efficiency.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

SublimeText3 Chinese version
Chinese version, very easy to use

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

Dreamweaver Mac version
Visual web development tools
