derby | 易学教程

Derby DB SQL, Select Rows starting from row number

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问题 How can I select From X rows to Y rows in a SQL in derby? For example: I would like to select row 15 - 30, but not top 15. Select all the row starting from row number 30. I tried LIMIT and ROWNUM do not work, how can I do it in derby? 回答1: According to the FAQ : Derby does not support the LIMIT syntax. However, Derby 10.4 added the ROW_NUMBER function and Derby 10.7 added the OFFSET and FETCH clauses. Derby also supports limiting the number of rows returned by a query through JDBC. <...>

关于derby数据库（新手教程）

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此内容来自专业的实训课，有错误欢迎指出。一：配置环境变量此电脑---右键-----属性---选择高级系统设置-----选择环境变量（1）加一个系统变量 DERBY_HOME %JAVA_HOME%DB （2）双击path %DERBY_HOME%\BIN （3）改Java_HOME的环境变量路径为db的存放位置。二：在命令行CMD输入ij看是否成功（没有报错）（1）先执行ij （2）建立一个数据库：connect'jdbc:derby:数据库的名字;create=true|false' 注意如果是已经存在的数据库前面的语句就可以不带create=true|false了。（3）建一个表(名字为mess)：create table mess(number char(10) primary key,name varchar (20),birth date,price double); （4）之后可以进行一些数据库操作了：查询：select * from mess; select name,price from mess; 插入：insert into mess value('2','中档狗','2020-01-11','1010'); 更新：update mess set price=2999 where number='3'; update mess set name=

Duplicate schema name in sequence generation

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问题 To prevent the usage of the schema attribute in the table annotation to all of my entities, I set the default schema name by the schema.xml: <?xml version="1.0" encoding="UTF-8"?> <entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd" version="2.0"> <persistence-unit-metadata> <persistence-unit-defaults> <schema>X</schema> </persistence-unit-defaults>

Duplicate schema name in sequence generation

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INSERT, and get the auto-incremented value

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问题 Consider the following table: create table language ( id integer generated always as identity (START WITH 1, INCREMENT BY 1), name long varchar, constraint language_pk primary key (id) ); To which I'd insert an entry this way. insert into language(name) values ('value'); How does one know what value for id was created? Just doing a SELECT using the name field is not valid, because there can be duplicate entries. 回答1: Through plain SQL: insert into language(name) values ('value'); SELECT

Derby - constraints

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问题 In the Derby server, how can you use the information in the system tables of the schema to create a select statement in order to retrieve the constraint names for each table? 回答1: The relevant manual is the Derby Reference Manual. There are many versions available: 10.13 was current in April 2017, but it was 10.3 in May 2009. Original answer SELECT c.constraintname, t.tablename FROM sysconstraints c, systables t WHERE c.tableid = t.tableid; Since sufficiently recent versions of Derby require

How can I start apache derby programmatically jar file?

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问题 I have a Java application, which uses Apache Derby. Using Eclipse Export option, I exported it as JAR file. When I am running Eclipse, and the server is connected to port 1527, the JAR executes correctly. However when eclipse is closed, (and the server is not connected to 1527) on executing jar, i get this error java.sql.SQLNonTransientConnectionException: java.net.ConnectException : Error connecting to server localhost on port 1527 with message Connection refused. This is understandable. But

用 Apache Derby 进行 ODBC 编程

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用 Apache Derby 进行 ODBC 编程 https://www.ibm.com/developerworks/cn/data/library/techarticles/dm-0409kartha/index.html https://www.ibm.com/developerworks/cn/data/library/techarticles/dm-0409kartha/index.html 来源： https://www.cnblogs.com/hzjdpawn/p/12153949.html

How do I Set a Key and a Value in a JFace ComboViewer?

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问题 I am trying to set up a combo box that will display a UserName, but when selected will send a an ID instead. I have already set up a method that queries my Derby database and returns a multidimensional array with the UserNames and IDs. I did some research on how to set this up and found several posts suggesting JFace, but nothing on how to accomplish this. I have tried setData(String Key, Object Value), and add(String String, int index). I have also looked at DataBinding, but haven't found

“IndexOutOfBoundsException” because of null values?

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问题 Please have a look at the following code DatabaseHandler.java public List getDetails(String name) { List details = new ArrayList(); name = name.replaceAll("\\s+", "").toUpperCase(); try { createConnection(); PreparedStatement ps = con.prepareStatement("select * from PhoneData where upper(rtrim(NULLIF(names,''))) || upper(rtrim(NULLIF(middleName,''))) || upper(rtrim(NULLIF(lastName,'')))=?"); ps.setString(1, name); ResultSet rs = ps.executeQuery(); // System.out.println("First Mobile Number: "