Solved Error executing DDL “alter table events drop foreign key

While running spring boot application I got following error

2021-10-22 13:38:59.732  WARN 700 --- [ restartedMain] o.h.t.s.i.ExceptionHandlerLoggedImpl  : GenerationTarget encountered exception accepting command : Error executing DDL "alter table users_roles add constraint FKt4v0rrweyk393bdgt107vdx0x foreign key (role_id) references role (id)" via JDBC Statement

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table users_roles add constraint FKt4v0rrweyk393bdgt107vdx0x foreign key (role_id) references role (id)" via JDBC Statement

Changed spring.jpa.hibernate.ddl-auto = create-drop to update. And changed table name user to users and role to roles.

Then problem has been solved

Spring and Gradle – adding to the project WebJars Bootstrap

If you wanted to add bootstrap UI CSS and JS files in thymeleaf then you can use following code:

<link th:href="@{/webjars/bootstrap/5.0.0/css/bootstrap.min.css}"
rel="stylesheet" media="screen" />
<script th:src="@{/webjars/bootstrap/5.0.0/js/bootstrap.min.js}"></script>

If those styles are still not loading then refresh project and if you are using spring security then you need to add following code in your extended class of

WebSecurityConfigurerAdapter
@Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.antMatchers("/", "/home","/webjars/**", "/resources/**").permitAll()
.anyRequest().authenticated()
.and()
.formLogin()
.loginPage("/login")
.permitAll()
.and()
.logout()
.permitAll();
}

It will solve your issue