resultset | 易学教程

Java JDBC 数据库链接小结随笔

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Java JDBC 数据库链接小结随笔一、链接数据库的步骤二、关于Statement 和 PrepareStatement 两者区别用法三、关于 ResultSet 的一些小结四、自定义工具类的封装五、一些异常的解释一、链接数据库的步骤注册驱动获得链接对象创建sql容器执行sql语句查询操作关闭资源：　　 1 package demo1; 2 3 import java.sql.*; 4 5 public class demo1 { 6 public static void main(String[] args) { 7 try { 8 Class.forName("com.mysql.cj.jdbc.Driver"); 9 String url="jdbc:mysql://127.0.0.1:3306/jdbc?serverTimezone=UTC"; 10 /*目前手动改变 sql 服务器时区报错问题*/ 11 String username="root"; 12 String password="root"; 13 /* com.mysql.cj.jdbc.Driver */ 14 15 Connection con= DriverManager.getConnection(url,username,password); 16

Mybatis JDBC->Mybatis

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　　1 什么是JDBC 　　Java程序都是通过JDBC（Java Data Base Connectivity）连接数据库的，通过SQL对数据库编程。JDBC是由SUN公司（SUN公司已被Oracle公司收购）提出的一系列规范，只定义了接口规范，具体的实现是由各个数据库厂商去完成的。因为每个数据库都有其特殊性，这些是Java规范没有办法确定的，所以JDBC就是一种典型的桥接模式。　　　　2 常用接口　　2.1 Driver接口　　要连接数据库，必须先加载特定厂商的数据库驱动程序，不同的数据库有不同的加载方法。共有2种方式。　　2.1.1 Class.forName("com.mysql.jdbc.Driver"); 　　推荐这种方式，不会对具体的驱动类产生依赖。　　例如： 1 // 加载Oracle驱动 2 Class.forName("oracle.jdbc.driver.OracleDriver"); 　　2.1.2 DriverManager.registerDriver("com.mysql.jdbc.Driver"); 　　会造成DriverManager中产生2个一样的驱动，并会对具体的驱动类产生依赖。　　2.2 Connection接口　　与特定数据库连接后，Connection执行SQL语句并返回结果。DriverManager

SQL query result from multiple tables without duplicates

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问题 I have a number of tables with filtered from all the records customer ID's, Last Order Date and that order Total $, Segment Name. Each filter is based on different criteria but, same customer ID can belong two different tables, two different segments. Same ID would have different values in Last Order and Total in . Segments, table names are A, B, C, D. I need to group the records from All the segment tables in a way that there are no duplicate ID's in the set. i.e.: if an ID appears in more

Java StoredProcedure with SqlReturnResultSet not working

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问题 I have this SP in my Dao class: private class ScoreStoredProcedure extends StoredProcedure { private static final String SPROC_NAME = "loadUserScore"; public ScoreStoredProcedure(DataSource datasource) { super(datasource, SPROC_NAME); declareParameter(new SqlReturnResultSet("score", mScoreMapper)); declareParameter(new SqlParameter("vusername", Types.VARCHAR)); declareParameter(new SqlParameter("vuuid", Types.VARCHAR)); declareParameter(new SqlParameter("vlimit", Types.INTEGER)); compile(); }

Any better approach rather than result.getString() while iterating a result set in java

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问题 I have 6 columns in a table. I have a select query which selects some records from the table. While iterating over the result set, im using the following logic to extract the values in the columns: Statement select = conn.createStatement(); ResultSet result = select.executeQuery ("SELECT * FROM D724933.ECOCHECKS WHERE ECO = '"+localeco+"' AND CHK_TOOL = '"+checknames[i]+"'"); while(result.next()) { // process results one row at a time String eco = result.getString(1); mapp2.put("ECO", eco);

how to add a relationship between tables in the dataset

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问题 I have the following code to get the get the relationship between the tables in the same dataset , but when run the following code i encounter with error saying , these columns currently dont have unique values DataResultSetDataSet dataset = resultSet as DataResultSetDataSet; System.Data.DataSet menuDataSet = new System.Data.DataSet(); menuDataSet = dataset.Set; menuDataSet.DataSetName = "Menus"; menuDataSet.Tables[0].TableName = "Menu"; DataRelation relation = new DataRelation("ParentChild",

Display Data Based on Date

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问题 I have 2 columns in a table in mysql which looks sometime like below, title timestamp -------------------- test1 1/7/2012 test2 1/7/2012 test3 1/7/2012 test4 2/7/2012 test5 3/7/2012. The result I am looking for is something like, **1/7/2012** test1 test3 **2/7/2012** test4 **3/7/2012** test5 Can someone help him here.can this be done just with MySQL query or I need to iterate the resultset in server side and then format the resultset for displaying. 回答1: You can use a query like this one:

How to update ResultSet in Sqlite in Java

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问题 I want to update my ResultSet with using SQLite in Java. When i am trying to update the Resultset it is giving me an exception : java.sql.SQLException: not implemented by SQLite JDBC driver . i have also done : stmt = c.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE); but still getting the exception, i think it is because we cannot update the result Set using SQLite DB. Please help that how can i update the Sqlite Resultset in java. 回答1: If you want to get

JDBC数据库连接七步走

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加载驱动方法 1.Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); 2. DriverManager.registerDriver(new com.mysql.jdbc.Driver()); 3.System.setProperty("jdbc.drivers", "com.mysql.jdbc.Driver"); 创建一个以JDBC连接数据库的程序，包含 7 个步骤： 1 、加载JDBC驱动程序：在连接数据库之前，首先要加载想要连接的数据库的驱动到JVM（Java虚拟机），这通过java.lang.Class类的静态方法forName(String className)实现。例如： try{ //加载MySql的驱动类 Class.forName("com.mysql.jdbc.Driver"); } catch(ClassNotFoundException e) { System.out.println("找不到驱动程序类，加载驱动失败！"); e.printStackTrace(); } 成功加载后，会将Driver类的实例注册到DriverManager类中。 2、提供JDBC连接的URL。例如： jdbc:mysql: //localhost:3306/test?useUnicode

简单的JDBC编程步骤

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1.加载数据库驱动（com.mysql.jdbc.Driver） 2.创建并获取数据库链接（Connection） 3.创建 jdbc statement 对象（PreparedStatement） 4.设置 sql 语句 5.设置 sql 语句中的参数 ( 使用 preparedStatement) 6.通过 statement 执行 sql 并获取结果 7.对 sql 执行结果进行解析处理 8.释放资源 (resultSet 、 preparedstatement 、 connection) package cn.wh.jdbc.test; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; /** * JdbcTest.java 简单的jdbc编程步骤过程 */ public class JdbcTest { public static void main(String[] args) { Connection connection = null; PreparedStatement preparedStatement =