schema | 易学教程

Postgres Creating Schema in a specific database

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问题 I got one suggestion form stackoverflow.com to create schema in a specific database as follows: CREATE DATABASE foo; \connect foo; CREATE SCHEMA yourschema; But I am getting error as follows: ERROR: syntax error at or near "\" LINE 2: \connect foo; ^ *** Error ** * ERROR: syntax error at or near "\" Situation : Login as postgress create user u1 create database db1 with owner u1 \connect u1 create schema s1 Please help me in creating schema in a specific db. 回答1: This works, if - and only if -

I want unique value for telephone element

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问题 I am learning xml and schema.I want a schema where Telephone element value have to be unique. I try with unique but can't understand how it's work. Sorry for this silly question but i am learning. xml <?xml version="1.0" encoding="utf-8" ?> <Company xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <Employee> <Name>ABC</Name> <Telephone>9998887770</Telephone> </Employee> <Employee> <Name>DEF</Name> <Telephone>9998887770</Telephone> </Employee> <Employee> <Name>GHI</Name> <Telephone

I want unique value for telephone element

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Boolean in nested schema causing required state

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问题 I have schemas set up so that I can have an array of complex input sets via autoform. Something like: address = { street:{ type: String }, city: { type: String }, active_address: { type: Boolean, optional: true }, ... } people: { name:{ type: String }, address:{ type: [address], optional: true, defaultValue: [] } } This way adding an address is optional, but if you add an address all of the address fields are required. Trying to submit the form throws a required error for every field under

dorm---2、manager创建控制器controllers（建包）pringmvc(springmvc.xml和web.xml头部约束)

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文章目录 1、创建两个包分别是java（Sources Root）和resources（Resources Root） 2、在web.xml中加载SpringMVC配置文件(拦截请求) 1、创建两个包分别是java（Sources Root）和resources（Resources Root） springmvc头部约束 <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans

How is XML a general data format?

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问题 We can use any tag of our choice in XML. If we have a DTD and style associate with it, we can parse it in browser. We can transfer data in XML format. But if XML tags are not fixed like HTML, how two systems come to know each other's meaning of the tags while talking (ex web services)? How can XML be a general data exchange language on the vast Internet?? 回答1: XML is a general language but pretty much any communication using XML will use a specific XML application such as XHTML, RDF, Atom,

How to store Goals (think RPG Quest) in SQL

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问题 Someone asked me today how they should store quest goals in a SQL database. In this context, think of an RPG. Goals could include some of the following: Discover [Location] Kill n [MOB Type] Acquire n of [Object] Achieve a [Skill] in [Skillset] All the other things you get in RPGs The best I could come up with is: Quest 1-* QuestStep QuestStep 1-* MobsToKill QuestStep 1-* PlacesToFind QuestStep 1-* ThingsToAcquire QuestStep 1-* etc. This seems a little clunky - Should they be storing a query

Spring MVC基础入门

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Spring MVC简介 Spring Web MVC是一种基于Java的实现了Web MVC设计模式的请求驱动类型的轻量级Web框架，即使用了MVC架构模式的思想，将web层进行职责解耦，基于请求驱动指的就是使用请求-响应模型，框架的目的就是帮助我们简化开发，Spring Web MVC也是要简化我们日常Web开发的。 Spring Web MVC处理请求的流程：具体执行步骤如下： 1、首先用户发送请求到前端控制器，前端控制器根据请求信息（如URL）来决定选择哪一个页面控制器进行处理并把请求委托给它； 2、页面控制器接收到请求后，进行功能处理，处理请求和创建相应的Model，处理完毕后返回一个ModelAndView（模型数据和逻辑视图名）； 3、前端控制器收回控制权，然后根据返回的逻辑视图名，选择相应的视图进行渲染，并把模型数据传入以便视图渲染； 4、前端控制器将响应返回给用户，至此整个结束。 Spring MVC Demo 写一个简单的例子来说明Spring MVC是如何工作的，该例子默认启动一个欢迎页面，并有一个login的页面，输入用户名和密码，当用户名和密码不为空返回“登录成功”，当输入有空时，则停留在login页面，例子非常简单。新建一个Dynamic Web Project。看web.xml的配置： <?xml version="1.0"

spark sql之RDD转换DataSet

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简介 Spark SQL提供了两种方式用于将RDD转换为Dataset。使用反射机制推断RDD的数据结构当spark应用可以推断RDD数据结构时，可使用这种方式。这种基于反射的方法可以使代码更简洁有效。通过编程接口构造一个数据结构，然后映射到RDD上当spark应用无法推断RDD数据结构时，可使用这种方式。反射方式 scala // For implicit conversions from RDDs to DataFrames import spark.implicits._ // Create an RDD of Person objects from a text file, convert it to a Dataframe val peopleDF = spark.sparkContext .textFile("examples/src/main/resources/people.txt") .map(_.split(",")) .map(attributes => Person(attributes(0), attributes(1).trim.toInt)) .toDF() // Register the DataFrame as a temporary view peopleDF.createOrReplaceTempView("people"

Spring Data Redis入门（demo）

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Spring Data Redis Redis redis是一款开源的Key-Value数据库，运行在内存中，由ANSI C编写。企业开发通常采用Redis来实现缓存。同类的产品还有memcache 、memcached 、MongoDB等 Jedis Jedis是Redis官方推出的一款面向Java的客户端，提供了很多接口供Java语言调用。可以在Redis官网下载，当然还有一些开源爱好者提供的客户端，如Jredis、SRP等等，推荐使用Jedis。 Spring Data Redis Spring-data-redis是spring大家族的一部分，提供了在srping应用中通过简单的配置访问redis服务，对reids底层开发包(Jedis, JRedis, and RJC)进行了高度封装，RedisTemplate提供了redis各种操作、异常处理及序列化，支持发布订阅，并对spring 3.1 cache进行了实现。 spring-data-redis针对jedis提供了如下功能： 1.连接池自动管理，提供了一个高度封装的“RedisTemplate”类 2.针对jedis客户端中大量api进行了归类封装,将同一类型操作封装为operation接口 ValueOperations：简单K-V操作 SetOperations：set类型数据操作 ZSetOperations

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