使用 Spring Boot 默认配置通过 JDBC 语句执行 DDL 时出错

Question

这是我在尝试将 Spring Boot 应用程序作为 java 应用程序运行时遇到的错误：
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL via JDBC Statement
Caused by: java.sql.SQLSyntaxErrorException: Schema 'SA' does not exist

我很乐意在 pom.xml 的属性中更改休眠方言（就像在其他类似主题中写的关于这个问题的一样），但它没有帮助。我还尝试更改主题类和字段的名称。
这是 pom.xml：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.julian.boot3</groupId>
    <artifactId>boot3</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>boot3</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

主类：

package com.julian.spring;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class App {

    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

POJO：

package com.julian.spring.pojo;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="topics")
public class Topic {

    @Id
    private Integer id;
    private String name;
    private String description;

    public Topic() {

    }

    public Topic(int id, String name, String description) {
        this.id = id;
        this.name = name;
        this.description = description;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

}

Answer 1

把它放在资源下的application.properties文件中：

spring.jpa.hibernate.ddl-auto=update

Answer 2

我通过将 spring-boot-starter-parent fomr 2.0.4.REALESE 的版本降级到 1.5.1.RELEASE 解决了这个问题

Answer 3

请阅读https://spring.io/guides/gs/accessing-data-mysql/这个，这是一个很常见的问题，如何安排与数据库的连接。

如果你不使用 MySQL，其他数据库也有文章，但对于关系数据库，都是一样的。