hibernate

问题 I have a web application with hibernate connection. application is connecting to PostgreSQL db. Some times I am getting below exceptions in my logs. Caused by: **org.postgresql.util.PSQLException: An I/O error occured while sending to the backend.** at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:283) at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:479) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags

问题 I have a web application with hibernate connection. application is connecting to PostgreSQL db. Some times I am getting below exceptions in my logs. Caused by: **org.postgresql.util.PSQLException: An I/O error occured while sending to the backend.** at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:283) at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:479) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags

问题 I am stuck with a issue of identify which constraint triggers DataIntegrityViolationException. I have two unique constraints: username and email but I have no luck trying to figure it out. I have tried to get the root cause exception but I got this message Unique index or primary key violation: "UK_6DOTKOTT2KJSP8VW4D0M25FB7_INDEX_4 ON PUBLIC.USERS(EMAIL) VALUES ('copeland@yahoo.com', 21)"; SQL statement: insert into users (id, created_at, updated_at, country, email, last_name, name, password,

问题 I am stuck with a issue of identify which constraint triggers DataIntegrityViolationException. I have two unique constraints: username and email but I have no luck trying to figure it out. I have tried to get the root cause exception but I got this message Unique index or primary key violation: "UK_6DOTKOTT2KJSP8VW4D0M25FB7_INDEX_4 ON PUBLIC.USERS(EMAIL) VALUES ('copeland@yahoo.com', 21)"; SQL statement: insert into users (id, created_at, updated_at, country, email, last_name, name, password,

问题 I am stuck with a issue of identify which constraint triggers DataIntegrityViolationException. I have two unique constraints: username and email but I have no luck trying to figure it out. I have tried to get the root cause exception but I got this message Unique index or primary key violation: "UK_6DOTKOTT2KJSP8VW4D0M25FB7_INDEX_4 ON PUBLIC.USERS(EMAIL) VALUES ('copeland@yahoo.com', 21)"; SQL statement: insert into users (id, created_at, updated_at, country, email, last_name, name, password,

问题 We're migrating data from a legacy Java app into our newer .NET app. The Java app has a MySQL backend, and the .NET app has a SQL Server back end. We have the full source code and config files for both, but none of the developers who worked on the Java app are still with the company, and we're having to reverse-engineer some of the logic in order to migrate the data. We have most of the data moving over properly in our tests. But there's one column with encrypted values that we're having

问题 We're migrating data from a legacy Java app into our newer .NET app. The Java app has a MySQL backend, and the .NET app has a SQL Server back end. We have the full source code and config files for both, but none of the developers who worked on the Java app are still with the company, and we're having to reverse-engineer some of the logic in order to migrate the data. We have most of the data moving over properly in our tests. But there's one column with encrypted values that we're having

问题 I have a Java/JPA/Hibernate/MySQL based app. I want to use UUIDs for object identity, however I want to ensure database performance does not suffer. I found this great blog posting JPA and UUID Primary Keys which gets me some of the way there. Notice how the storage of the UUID is optimized by storing it in binary form (versus the string representation. It solves part of the problem, because now we can insert objects efficiently into the database. However, now I have an issue when I want to

问题 In order to generate the next SQL code: create table users ( user_name varchar(15) not null primary key, user_pass varchar(15) not null); create table user_roles( username varchar(15) not null, role_name varchar(15) not null, primary key(usernmae, rolename) ); You can use code such as: <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="databaselayer

问题 In order to generate the next SQL code: create table users ( user_name varchar(15) not null primary key, user_pass varchar(15) not null); create table user_roles( username varchar(15) not null, role_name varchar(15) not null, primary key(usernmae, rolename) ); You can use code such as: <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <class name="databaselayer