Creating field with reserved word name with JPA

问题:

@Column(name=\"open\")

Using sqlserver dialect with hibernate.

[SchemaUpdate] Unsuccessful: create table auth_session (id numeric(19,0) identity not null, active tinyint null, creation_date datetime not null, last_modified datetime not null, maxidle int null, maxlive int null, open tinyint null, sessionid varchar(255) not null, user_id numeric(19,0) not null, primary key (id), unique (sessionid))
[SchemaUpdate] Incorrect syntax near the keyword \'open\'.

I would have expected hibernate to use quoted identifier when creating the table.

Any ideas on how to handle this... other than renaming the field?

回答1:

Had the same problem, but with a tablename called Transaction. If you set

hibernate.globally_quoted_identifiers=true

Then all database identifiers will be quoted.

Found my answer here Special character in table name hibernate giving error

And found all available settings here https://docs.jboss.org/hibernate/orm/5.2/userguide/html_single/appendices/Configurations.html

Could not find better docs for this though.

回答2:

With Hibernate as JPA 1.0 provider, you can escape a reserved keyword by enclosing it within backticks:

@Column(name=\"`open`\")

This is the syntax inherited from Hiberate Core:

5.4. SQL quoted identifiers

You can force Hibernate to quote an identifier in the generated SQL by enclosing the table or column name in backticks in the mapping document. Hibernate will use the correct quotation style for the SQL Dialect. This is usually double quotes, but the SQL Server uses brackets and MySQL uses backticks.

<class name=\"LineItem\" table=\"`Line Item`\">
    <id name=\"id\" column=\"`Item Id`\"/><generator class=\"assigned\"/></id>
    <property name=\"itemNumber\" column=\"`Item #`\"/>
    ...
</class>

In JPA 2.0, the syntax is standardized and becomes:

@Column(name=\"\\\"open\\\"\")

References

• Hibernate reference guide
  • 5.4. SQL quoted identifiers
• JPA 2.0 specification
  • 2.13 Naming of Database Objects

Related questions

• Hibernate, MySQL and table named “Repeat” - strange behaviour
• Automatic reserved word escaping for Hibernate tables and columns

回答3:

If you use as shown below it should work

@Column(name=\"[order]\")
private int order;

回答4:

@Column(name=\"\\\"open\\\"\")

This will work for sure, Same problem happened with me, when I was learning hibernate.

回答5:

No - change the column name.

This is database-specific, and you just can\'t create such a column. After all hibernate finally sends DDL to the database. If you can\'t create a valid DDL with this column name, this means hibernate can\'t as well. I don\'t think quoting would solve the issue even if you are writing the DDL.

Even if you somehow succeed to escape the name - change it. It will work with this database, but won\'t work with another.

回答6:

Some JPA implementations (e.g the one I use, DataNucleus) automatically quote the identifier for you, so you never get this.