小编Vis*_*kar的帖子

主要功能如下：

mod stats;

fn main() {
    let raw_data = [10, 10, 20, 1, 2, 3, 5];
    let mut v: Vec<u32> = Vec::new();
    let mean = 0;
    let median = 0;
    let mode = 0;
    for i in raw_data.iter() {
        v.push(*i);
    }
    let stat = stats::stats::Stats::new(v);
}

模块统计信息如下：

pub mod stats {
    pub struct Stats {
        data: Vec<u32>,
    }
    impl Stats {
        pub fn new(data: Vec<u32>) -> Stats {
            Stats { data }
        }
        pub fn find_mean(&self) -> f64 {
            let …

我正在开发一个 Rest API，用于从数据库中获取所有主题。我将 Spring Boot 与 Derby 结合使用，并使用 JPA 与 derby 进行交互。当 Spring Boot 应用程序启动时，JPA 无法在 derby 上创建表并抛出错误。

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table topic (id bigint not null, desc varchar(255), name varchar(255), primary key (id))" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:440) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:424) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:315) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:166) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:135) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:121) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:155) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:72) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:310) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:467) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:939) [hibernate-core-5.3.9.Final.jar:5.3.9.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) [spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) …