Why Spring turn a column name from camelNaming to snake_Naming

Don’t spend another year doing the same shit.

Why Spring turn a column name from camelNaming to snake_Naming?

Symptoms:

There is one ‘column name xx is not valid’ in SQLServerException, below is one sample console output

by: com.microsoft.sqlserver.jdbc.SQLServerException: The column name v_book is not valid.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:234)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.findColumn(SQLServerResultSet.java:699)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getString(SQLServerResultSet.java:2525)
at com.zaxxer.hikari.pool.HikariProxyResultSet.getString(HikariProxyResultSet.java)
at org.hibernate.type.descriptor.sql.VarcharTypeDescriptor$2.doExtract(VarcharTypeDescriptor.java:62)
at org.hibernate.type.descriptor.sql.BasicExtractor.extract(BasicExtractor.java:47)
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:257)
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:253)
at org.hibernate.type.AbstractStandardBasicType.nullSafeGet(AbstractStandardBasicType.java:243)
at org.hibernate.type.AbstractStandardBasicType.hydrate(AbstractStandardBasicType.java:329)

SpringData explained & Troubleshooting:

In short answer, this is caused by default NamingStrategy implementation , which is SpringPhysicalNamingStrategy assigned by SpringBoot Data . Which is trying to smartly guess and set it up as default naming strategy provider.

Under the hood, it’s implementation (listed as below)

@Override
  public Identifier toPhysicalColumnName(Identifier name, JdbcEnvironment jdbcEnvironment) {
        return apply(name, jdbcEnvironment);
 }
....
private boolean isUnderscoreRequired(char before, char current, char after) {
        return Character.isLowerCase(before) && Character.isUpperCase(current) && Character.isLowerCase(after);
    }

It will change camelNaming to snake_naming, for example, myColumn will be translated to my_Column , which is align with Spring’s naming convention.

As below sample column transformation: vCriteria will be changed to v_Criteria

Here’s the code logic FYI.

Solution

There are few solutions for the fix

Disable NamingStrategy

Firstly and quickest one: remove annotation of @Column, this is actually the marker annotation to trigger Spring’s naming strategy logic.

Chose another NamingStrategy

If you still need annotation @Column (e.g. for calculation or columnDefinition), you can explicitly change its naming strategy, such as below sample:

spring:
  jpa:
    hibernate:
      naming:
        physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

This PhysicalNamingStrategyStandardImpl is one of two implementations of Hibernate’s PhysicalNamingStrategy interface. It’s logic is straightforward, purely return whatever the name it get from database.

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