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); CREATE PROCEDURE login_ning(IN p_id int,IN p_pwd int,OUT flag int)BEGINDECLARE v_pwd int; select pwd INTO v_pwd from users_ning where id = p_id; if v_pwd = p_pwd then set 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 <= size; i++) {<span style="white-space:pre"> </span>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 < num) {<span style="white-space:pre"> </span>for (int k = size + 1; k <= num; k++) {<span style="white-space:pre"> </span>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 <= size; i++) {<span style="white-space:pre"> </span>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 <= size; i++) {<span style="white-space:pre"> </span>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 <= size; i++) {<span style="white-space:pre"> </span>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 < num) {<span style="white-space:pre"> </span>for (int k = size + 1; k <= num; k++) {<span style="white-space:pre"> </span>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 <= rsmd.getColumnCount(); i++) {<span style="white-space:pre"> </span>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 <= rsmd.getColumnCount(); i++) {<span style="white-space:pre"> </span>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 <= rsmd.getColumnCount(); i++) {<span style="white-space:pre"> </span>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 <= rsmd.getColumnCount(); i++) {<span style="white-space:pre"> </span>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>}}

ACID属性包括原子性、一致性、隔离性和持久性,是数据库设计的基石。1.原子性确保事务要么完全成功,要么完全失败。2.一致性保证数据库在事务前后保持一致状态。3.隔离性确保事务之间互不干扰。4.持久性确保事务提交后数据永久保存。

MySQL既是数据库管理系统(DBMS),也与编程语言紧密相关。1)作为DBMS,MySQL用于存储、组织和检索数据,优化索引可提高查询性能。2)通过SQL与编程语言结合,嵌入在如Python中,使用ORM工具如SQLAlchemy可简化操作。3)性能优化包括索引、查询、缓存、分库分表和事务管理。

MySQL使用SQL命令管理数据。1.基本命令包括SELECT、INSERT、UPDATE和DELETE。2.高级用法涉及JOIN、子查询和聚合函数。3.常见错误有语法、逻辑和性能问题。4.优化技巧包括使用索引、避免SELECT*和使用LIMIT。

MySQL是一种高效的关系型数据库管理系统,适用于存储和管理数据。其优势包括高性能查询、灵活的事务处理和丰富的数据类型。实际应用中,MySQL常用于电商平台、社交网络和内容管理系统,但需注意性能优化、数据安全和扩展性。

SQL和MySQL的关系是标准语言与具体实现的关系。1.SQL是用于管理和操作关系数据库的标准语言,允许进行数据的增、删、改、查。2.MySQL是一个具体的数据库管理系统,使用SQL作为其操作语言,并提供高效的数据存储和管理。

InnoDB使用redologs和undologs确保数据一致性和可靠性。1.redologs记录数据页修改,确保崩溃恢复和事务持久性。2.undologs记录数据原始值,支持事务回滚和MVCC。

EXPLAIN命令的关键指标包括type、key、rows和Extra。1)type反映查询的访问类型,值越高效率越高,如const优于ALL。2)key显示使用的索引,NULL表示无索引。3)rows预估扫描行数,影响查询性能。4)Extra提供额外信息,如Usingfilesort提示需要优化。

Usingtemporary在MySQL查询中表示需要创建临时表,常见于使用DISTINCT、GROUPBY或非索引列的ORDERBY。可以通过优化索引和重写查询避免其出现,提升查询性能。具体来说,Usingtemporary出现在EXPLAIN输出中时,意味着MySQL需要创建临时表来处理查询。这通常发生在以下情况:1)使用DISTINCT或GROUPBY时进行去重或分组;2)ORDERBY包含非索引列时进行排序;3)使用复杂的子查询或联接操作。优化方法包括:1)为ORDERBY和GROUPB


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