create table users_ning(id primary key auto_increment,pwd int); insert into users_ning values(id,1234);insert into users_ning values(id,12345); insert into users_ning values(id,12); insert into users_ning values(id,123);CREATEPROCEDURE login_ning(IN p_id int,IN p_pwd int,OUT flag int)BEGINDECLARE v_pwd int;select pwd INTO v_pwd from users_ningwhere id = p_id; if v_pwd = p_pwd thenset flag:=1;else select v_pwd;set flag := 0;end if;END package demo20130528;import java.sql.*;import demo20130526.DBUtils;/** * 测试JDBC API调用过程 * @author tarena * */public class ProcedureDemo2 {/** * @param args * @throws Exception*/public static void main(String[] args) throws Exception {System.out.println(login(123, 1234));}/** * 调用过程,实现登录功能 * @param id 考生id * @param pwd 考试密码 * @return if成功:1; if密码错:0; if没有用户:-1 * @throws Exception*/public static int login(int id, int pwd) throws Exception{int flag = -1;String sql = "{call login_ning(?,?,?)}";//*****Connection conn = DBUtils.getConnMySQL();CallableStatement stmt = null;try{stmt = conn.prepareCall(sql);//传递输入参数stmt.setInt(1, id);stmt.setInt(2, pwd);//注册输出参数,第三个占位符的数据类型是整型stmt.registerOutParameter(3, Types.INTEGER);//*****//执行过程stmt.execute();//获得过程执行后的输出参数flag = stmt.getInt(3);//*****}catch(Exception e){e.printStackTrace();}finally{stmt.close();DBUtils.dbClose();}return flag;}}
package demo20130526;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.sql.Connection;import java.sql.DatabaseMetaData;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.ResultSetMetaData;import java.sql.SQLException;import java.sql.Statement;import java.util.Properties;public class DBUtils {<span style="white-space:pre"> </span>static Connection conn = null;<span style="white-space:pre"> </span>static PreparedStatement stmt = null;<span style="white-space:pre"> </span>static ResultSet rs = null;<span style="white-space:pre"> </span>static Statement st = null;<span style="white-space:pre"> </span>static String username = null;<span style="white-space:pre"> </span>static String password = null;<span style="white-space:pre"> </span>static String url = null;<span style="white-space:pre"> </span>static String driverName = null;<span style="white-space:pre"> </span>public static Connection getConnMySQL() throws Exception {// 连接mysql 返回conn<span style="white-space:pre"> </span>getUrlUserNamePassWordClassNameMySQL();<span style="white-space:pre"> </span>conn = DriverManager.getConnection(url, username, password);<span style="white-space:pre"> </span>// conn.setAutoCommit(false);设置自动提交为false<span style="white-space:pre"> </span>return conn;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static Connection getConnORCALE() throws Exception {// 连接orcale<span style="white-space:pre"> </span>// 返回conn<span style="white-space:pre"> </span>getUrlUserNamePassWordClassNameORCALE();<span style="white-space:pre"> </span>conn = DriverManager.getConnection(url, username, password);<span style="white-space:pre"> </span>// conn.setAutoCommit(false);<span style="white-space:pre"> </span>return conn;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>private static void getUrlUserNamePassWordClassNameORCALE()<span style="white-space:pre"> </span>throws Exception {<span style="white-space:pre"> </span>// 从资源文件 获取 orcale的username password url等信息<span style="white-space:pre"> </span>Properties pro = new Properties();<span style="white-space:pre"> </span>File path = new File("src/all.properties");<span style="white-space:pre"> </span>pro.load(new FileInputStream(path));<span style="white-space:pre"> </span>String paths = pro.getProperty("filepath");<span style="white-space:pre"> </span>File file = new File(paths + "orcale.properties");<span style="white-space:pre"> </span>getFromProperties(file);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getUrlUserNamePassWordClassNameMySQL() throws Exception {<span style="white-space:pre"> </span>// 从资源文件 获取mysql的username password url等信息<span style="white-space:pre"> </span>Properties pro = new Properties();<span style="white-space:pre"> </span>File path = new File("src/all.properties");<span style="white-space:pre"> </span>pro.load(new FileInputStream(path));<span style="white-space:pre"> </span>String paths = pro.getProperty("filepath");<span style="white-space:pre"> </span>File file = new File(paths + "mysql.properties");<span style="white-space:pre"> </span>getFromProperties(file);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getFromProperties(File file) throws IOException,<span style="white-space:pre"> </span>FileNotFoundException, ClassNotFoundException {// 读资源文件的内容<span style="white-space:pre"> </span>Properties pro = new Properties();<span style="white-space:pre"> </span>pro.load(new FileInputStream(file));<span style="white-space:pre"> </span>username = pro.getProperty("username");<span style="white-space:pre"> </span>password = pro.getProperty("password");<span style="white-space:pre"> </span>url = pro.getProperty("url");<span style="white-space:pre"> </span>driverName = pro.getProperty("driverName");<span style="white-space:pre"> </span>Class.forName(driverName);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void dbClose() throws Exception {// 关闭所有<span style="white-space:pre"> </span>if (rs != null)<span style="white-space:pre"> </span>rs.close();<span style="white-space:pre"> </span>if (st != null)<span style="white-space:pre"> </span>st.close();<span style="white-space:pre"> </span>if (stmt != null)<span style="white-space:pre"> </span>stmt.close();<span style="white-space:pre"> </span>if (conn != null)<span style="white-space:pre"> </span>conn.close();<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static ResultSet getById(String tableName, int id) throws Exception {// 用id来查询结果<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>rs = st.executeQuery("select * from " + tableName + "where id=" + id<span style="white-space:pre"> </span>+ " ");<span style="white-space:pre"> </span>return rs;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static ResultSet getByAll(String sql, Object... obj)<span style="white-space:pre"> </span>throws Exception {// 用关键字 实现查询 关键字额可以任意<span style="white-space:pre"> </span>sql = sql.replaceAll(";", "");<span style="white-space:pre"> </span>sql = sql.trim();<span style="white-space:pre"> </span>stmt = conn.prepareStatement(sql);<span style="white-space:pre"> </span>String[] strs = sql.split("//?");// 将sql 以? 非开<span style="white-space:pre"> </span>int num = strs.length;// 得到?的个数<span style="white-space:pre"> </span>int size = obj.length;<span style="white-space:pre"> </span>for (int i = 1; i stmt.setObject(i, obj[i - 1]);// 数组下标从0开始<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>if (size for (int k = size + 1; k stmt.setObject(k, null);// 数组下标从0开始<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>rs = stmt.executeQuery();<span style="white-space:pre"> </span>return rs;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void doInsert(String sql) throws SQLException {// 传入 sql 语句<span style="white-space:pre"> </span>// 实现插入操作<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>st.execute(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void doInsert(String sql, Object... args) throws Exception {// 传入参数<span style="white-space:pre"> </span>// 利用<span style="white-space:pre"> </span>// PreparedStatement<span style="white-space:pre"> </span>// 实现插入<span style="white-space:pre"> </span>// 传入的参数是任意多个 因为有Object 。。。args<span style="white-space:pre"> </span>int size = args.length;// 获得 Object ...obj 传过来的参数的个数<span style="white-space:pre"> </span>stmt = conn.prepareStatement(sql);<span style="white-space:pre"> </span>for (int i = 1; i stmt.setObject(i, args[i - 1]);// 数组下标从0开始<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>stmt.execute();<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static int doUpdate(String sql) throws Exception {// 传入 sql 实现更新操作<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>int num = st.executeUpdate(sql);<span style="white-space:pre"> </span>return num;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void doUpdate(String sql, Object... obj) throws Exception {<span style="white-space:pre"> </span>// 传入参数 利用 PreparedStatement实现更新<span style="white-space:pre"> </span>// 传入的参数是任意多个 因为有Object 。。。args<span style="white-space:pre"> </span>int size = obj.length;// 获得 Object ...obj 传过来的参数的个数<span style="white-space:pre"> </span>stmt = conn.prepareStatement(sql);<span style="white-space:pre"> </span>for (int i = 1; i stmt.setObject(i, obj[i - 1]);// 数组下标从0开始<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>stmt.executeUpdate(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static boolean doDeleteById(String tableName, int id)<span style="white-space:pre"> </span>throws SQLException {// 删除记录 by id<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>boolean b = st.execute("delete from " + tableName + " where id=" + id<span style="white-space:pre"> </span>+ "");<span style="white-space:pre"> </span>return b;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static boolean doDeleteByAll(String sql, Object... args)<span style="white-space:pre"> </span>throws SQLException {// 删除记录 可以按任何关键字<span style="white-space:pre"> </span>sql = sql.replaceAll(";", "");<span style="white-space:pre"> </span>sql = sql.trim();<span style="white-space:pre"> </span>stmt = conn.prepareStatement(sql);<span style="white-space:pre"> </span>String[] strs = sql.split("//?");// 将sql 以? 非开<span style="white-space:pre"> </span>int num = strs.length;// 得到?的个数<span style="white-space:pre"> </span>int size = args.length;<span style="white-space:pre"> </span>for (int i = 1; i stmt.setObject(i, args[i - 1]);// 数组下标从0开始<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>if (size for (int k = size + 1; k stmt.setObject(k, null);// 数组下标从0开始<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>boolean b = stmt.execute();<span style="white-space:pre"> </span>return b;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getMetaDate() throws Exception {// 获取数据库元素数据<span style="white-space:pre"> </span>conn = DBUtils.getConnORCALE();<span style="white-space:pre"> </span>DatabaseMetaData dmd = conn.getMetaData();<span style="white-space:pre"> </span>System.out.println(dmd.getDatabaseMajorVersion());<span style="white-space:pre"> </span>System.out.println(dmd.getDatabaseProductName());<span style="white-space:pre"> </span>System.out.println(dmd.getDatabaseProductVersion());<span style="white-space:pre"> </span>System.out.println(dmd.getDatabaseMinorVersion());<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static String[] getColumnNamesFromMySQL(String sql) throws Exception {<span style="white-space:pre"> </span>conn = DBUtils.getConnMySQL();<span style="white-space:pre"> </span>return getColumnName(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static String[] getColumnNamesFromOrcale(String sql)<span style="white-space:pre"> </span>throws Exception {<span style="white-space:pre"> </span>conn = DBUtils.getConnORCALE();<span style="white-space:pre"> </span>return getColumnName(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>private static String[] getColumnName(String sql) throws Exception {// 返回表中所有的列名<span style="white-space:pre"> </span>conn = DBUtils.getConnORCALE();<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>rs = st.executeQuery(sql);<span style="white-space:pre"> </span>ResultSetMetaData rsmd = rs.getMetaData();<span style="white-space:pre"> </span>int num = rsmd.getColumnCount();<span style="white-space:pre"> </span>System.out.println("ColumnCount=" + num);<span style="white-space:pre"> </span>String[] strs = new String[num];<span style="white-space:pre"> </span>// 显示列名<span style="white-space:pre"> </span>for (int i = 1; i String str = rsmd.getColumnName(i);<span style="white-space:pre"> </span>strs[i - 1] = str;<span style="white-space:pre"> </span>System.out.print(str + "/t");<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>return strs;<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getColumnDataFromMySQL(String sql) throws Exception {// 输出表中的数据<span style="white-space:pre"> </span>conn = DBUtils.getConnMySQL();<span style="white-space:pre"> </span>getColumnData(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getColumnDataFromORCALEL(String sql) throws Exception {// 输出表中的数据<span style="white-space:pre"> </span>conn = DBUtils.getConnORCALE();<span style="white-space:pre"> </span>getColumnData(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getColumnData(String sql) throws Exception {// 输出表中的数据<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>rs = st.executeQuery(sql);<span style="white-space:pre"> </span>ResultSetMetaData rsmd = rs.getMetaData();<span style="white-space:pre"> </span>System.out<span style="white-space:pre"> </span>.println("/n------------------------------------------------------------------------------------------------------------------------");<span style="white-space:pre"> </span>while (rs.next()) {<span style="white-space:pre"> </span>for (int i = 1; i System.out.print(rs.getString(i) + "/t");<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>System.out.println();<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>System.out<span style="white-space:pre"> </span>.println("------------------------------------------------------------------------------------------------------------------------");<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getTableDataFromOrcale(String sql) throws Exception {// 输出表的列名<span style="white-space:pre"> </span>// 和表中的全部数据<span style="white-space:pre"> </span>conn = DBUtils.getConnORCALE();<span style="white-space:pre"> </span>getTableData(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>public static void getTableDataFromMysql(String sql) throws Exception {// 输出表的列名<span style="white-space:pre"> </span>// 和表中的全部数据<span style="white-space:pre"> </span>conn = DBUtils.getConnMySQL();<span style="white-space:pre"> </span>getTableData(sql);<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>private static void getTableData(String sql) throws SQLException {<span style="white-space:pre"> </span>// getTableDataFromMysql<span style="white-space:pre"> </span>// getTableDataFromOrcale<span style="white-space:pre"> </span>st = conn.createStatement();<span style="white-space:pre"> </span>rs = st.executeQuery(sql);<span style="white-space:pre"> </span>ResultSetMetaData rsmd = rs.getMetaData();<span style="white-space:pre"> </span>int num = rsmd.getColumnCount();<span style="white-space:pre"> </span>System.out.println("ColumnCount=" + num);<span style="white-space:pre"> </span>String[] strs = new String[num];<span style="white-space:pre"> </span>// 显示列名<span style="white-space:pre"> </span>for (int i = 1; i String str = rsmd.getColumnName(i);<span style="white-space:pre"> </span>strs[i - 1] = str;<span style="white-space:pre"> </span>System.out.print(str + "/t");<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>System.out<span style="white-space:pre"> </span>.println("/n------------------------------------------------------------------------------------------------------------------------");<span style="white-space:pre"> </span>while (rs.next()) {<span style="white-space:pre"> </span>for (int i = 1; i System.out.print(rs.getString(i) + "/t");<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>System.out.println();<span style="white-space:pre"> </span>}<span style="white-space:pre"> </span>System.out<span style="white-space:pre"> </span>.println("------------------------------------------------------------------------------------------------------------------------");<span style="white-space:pre"> </span>}}

在數據庫優化中,應根據查詢需求選擇索引策略:1.當查詢涉及多個列且條件順序固定時,使用複合索引;2.當查詢涉及多個列但條件順序不固定時,使用多個單列索引。複合索引適用於優化多列查詢,單列索引則適合單列查詢。

要優化MySQL慢查詢,需使用slowquerylog和performance_schema:1.啟用slowquerylog並設置閾值,記錄慢查詢;2.利用performance_schema分析查詢執行細節,找出性能瓶頸並優化。

MySQL和SQL是開發者必備技能。 1.MySQL是開源的關係型數據庫管理系統,SQL是用於管理和操作數據庫的標準語言。 2.MySQL通過高效的數據存儲和檢索功能支持多種存儲引擎,SQL通過簡單語句完成複雜數據操作。 3.使用示例包括基本查詢和高級查詢,如按條件過濾和排序。 4.常見錯誤包括語法錯誤和性能問題,可通過檢查SQL語句和使用EXPLAIN命令優化。 5.性能優化技巧包括使用索引、避免全表掃描、優化JOIN操作和提升代碼可讀性。

MySQL異步主從復制通過binlog實現數據同步,提升讀性能和高可用性。 1)主服務器記錄變更到binlog;2)從服務器通過I/O線程讀取binlog;3)從服務器的SQL線程應用binlog同步數據。

MySQL是一個開源的關係型數據庫管理系統。 1)創建數據庫和表:使用CREATEDATABASE和CREATETABLE命令。 2)基本操作:INSERT、UPDATE、DELETE和SELECT。 3)高級操作:JOIN、子查詢和事務處理。 4)調試技巧:檢查語法、數據類型和權限。 5)優化建議:使用索引、避免SELECT*和使用事務。

MySQL的安裝和基本操作包括:1.下載並安裝MySQL,設置根用戶密碼;2.使用SQL命令創建數據庫和表,如CREATEDATABASE和CREATETABLE;3.執行CRUD操作,使用INSERT,SELECT,UPDATE,DELETE命令;4.創建索引和存儲過程以優化性能和實現複雜邏輯。通過這些步驟,你可以從零開始構建和管理MySQL數據庫。

InnoDBBufferPool通過將數據和索引頁加載到內存中來提升MySQL數據庫的性能。 1)數據頁加載到BufferPool中,減少磁盤I/O。 2)臟頁被標記並定期刷新到磁盤。 3)LRU算法管理數據頁淘汰。 4)預讀機制提前加載可能需要的數據頁。

MySQL適合初學者使用,因為它安裝簡單、功能強大且易於管理數據。 1.安裝和配置簡單,適用於多種操作系統。 2.支持基本操作如創建數據庫和表、插入、查詢、更新和刪除數據。 3.提供高級功能如JOIN操作和子查詢。 4.可以通過索引、查詢優化和分錶分區來提升性能。 5.支持備份、恢復和安全措施,確保數據的安全和一致性。


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