I have a user stored in oracle DB and one of the fields is stored as a CLOB(a simple Json {"profile": "man"}). I am using Mybatis and i try to retrieve the value.
So i am having:
<resultMap id=userResults>
<property="details" column="DETAILS" jdbcType="CLOB"
javaType="String"
typeHandler="org.apache.ibatis.type.ClobTypeHandler"
</resultMap>
and in the POJO:
the field details as a String with getter and setter.
class User{
private String name;
private String surname;
private String details;
//getters + setters
}
But nothing mapped in the end, even though the row exists in the DB.
The query is:
Select * FROM USER Where USER.id = #{id}
Any recommendations?
After some conversation on comments it turns out that the problem was the Oracle JDBC Driver after suggesting it and OP upgrading it He was able to make it work.
Related
I'm trying to make a query to retrieve some data which has been created between two dates (represented as Instant).
Here below an extract from the Entity I'm using:
#Entity
public class HistoricalData {
#Id
#GeneratedValue
private Long id;
#Column
private String name;
#CreationTimestamp
private Instant timestamp;
#Column
private Double price;
}
And the query I've written to retrieve the data between the two Instants;
#Query("select h from HistoricalData h where h.timestamp between :timestampStart and :timestampEnd and upper(name) = upper(:name)")
List<HistoricalData> findHistoricalDataBetween(#NonNull Instant timestampStart, #NonNull Instant timestampEnd, #NonNull String name);
Which produces this SQL query:
select historical0_.id as id1_5_, historical0_.price as price2_5_, historical0_.timestamp as timestam3_5_ from historical_data historical0_ where (historical0_.timestamp between ? and ?) and upper(historical0_.name)=upper(?)
Also I wrote the "hibernate JPA" query just to try but no success:
List<HistoricalData> findHistoricalDataByTimestampAfterAndTimestampBeforeAndName(#NonNull Instant timestampStart, #NonNull Instant timestampEnd, #NonNull String name);
Keep in mind that all the above queries compile correctly and do not throw any exception, they just retrieve nothing from the database
The database I'm using is a latest version of MariaDB and the connector version is the 2.7.2
Also the SpringBoot version I'm using is the 2.5.3
Here is DDL from the table definition (automatically generated from Hibernate):
create table historical_data
(
id bigint not null primary key,
price double null,
timestamp datetime not null,
name varchar not null
);
An this is how the timestamp looks like in the database:
Even though records between those two Instants are present in the database I'm still getting nothing as a result from the query.
Looks like the reason is a time zone.
MySQL driver uses incorrect time zone transformations, using a default local time zone in place of a connection time zone (or vice versa).
Just debug this query inside MySQL driver to have fun and figure out what happens.
You can add parameters to the database URL to see which actual values are passed for the prepare statement
jdbc:mysql://<DATABASE_URL>?logger=com.mysql.cj.log.Slf4JLogger&profileSQL=true
I'm trying to deserialise a one to many association with JooQ (without code generation) as per this post.
Here are my target classes.
public class Author {
private Long id;
private String name;
private List<Book> books;
}
public class Book {
private String name;
}
My JooQ query is as follows:
dslContext
.select(table("authors").asterisk(),
field(
select(jsonArrayAgg(
jsonObject(
jsonEntry("name", field("books.name")))))
.from(table("books"))
.join(table("authors"))
.on(field("books.author_id").eq(field("authors.id")))
.where(field("emails.collection_case_id")
.eq(field("collection_cases.id")))
).as("books"))
.from(table("authors"))
.where(trueCondition())
.fetchInto(Author.class);
The jsonObject() method does not work as expected for me. The generated SQL statement looks something like this:
select authors.*, (select json_agg(json_build_object(?, books.name)) from books join authors ...
The translated postgres query has not properly replaced the key attribute of json_build_object and this results in SQL exception.
PS: I'm using JooQ 3.14.0 with postgres 11.5
While I can't reproduce this issue on my side with various PostgreSQL server and JDBC driver versions, the simple workaround here is to use DSL.inline(String) to prevent jOOQ's generating a bind variable for the json_build_object() function argument:
jsonEntry(inline("name"), field("books.name"))
required format image
I want to object data into MongoDB using spring and I have hardcoded it.
please how to write a schema for that and I have taken it as an example only.
I have a different type of categories in it I have taken only clothes.
please tell me how to write one schema for a different type of categories and query too.
please find the attachment for your reference
I would recommend going though Spring Data MongoDB documentation for specifics on mapping java objects to MongoDB documents. Your case would look similar to:
#Document
public class Clothes {
#Id
private ObjectId id;
private Men men;
private Women women;
// getters & setters
}
You would need to define each sub class but this should be the gist of it.
What you can do is create a simple POJO (Plain Old Java Object) and with that you can insert that object into the data base. The the following example:
#Document
public class OAuthModel implements Serializable {
#Id
String username;
#Indexed
String oAuthID;
#Indexed
String type;
// Getter and Setters and Construct.
}
When I insert this object in the DB by calling:
OAuthModel authModel = new OAuthModel(username,firebaseToken.getUid(), OAuthHosts.GOOGLE.getType());
oAuthRepo.insert(authModel);
It will then be seen as this in the Database:
Keep in mind this will work no matter what your object looks like, you can have hashmaps etc. The should be a built in serialization.
My Data model is
#Getter
#Setter
public class Customer {
#Id private ID id;
#CreatedDate protected Instant createdAt;
#LastModifiedDate protected Instant updatedAt;
#CreatedBy protected String createdBy;
#LastModifiedBy protected String updatedBy;
#Version protected Long version;
private UUID orderId;
private String offer;
}
My Repository is
public interface CustomerRepository extends CrudRepository<Customer, UUID> {
#Query(
"SELECT ID, Offer FROM Customer WHERE orderId = :orderId ")
List<Customer> findCustomerByOrderId(
#Param("orderId") UUID orderId);
}
This will result in an exception saying 'orderId column not found [42122-190]'. So Spring expects you to always query all the columns. I understand that with JPA we have a strong mapping between the Entities and the Data Schema. But the whole point of spring data JDBC is avoiding the tight coupling between POJO's data model and database schema. Why not the EntityRowMapper is just mapping NULL to the properties which are not part of the query?
Is there a way to tell the RowMapper used, to ignore properties which are not part of the query? Creating separate RowMapper for these simple queries seems a lot of unnecessary work.
I still can work around this by changing the query like
#Query(
"SELECT ID, Offer, OrderId, null as CreatedAt, null as CreatedBy, null as UpdatedAt, null as UpdatedBy, null as Version FROM Customer WHERE orderId = :orderId ")
But this will still serialize the entire object with null values. Am I missing something obvious here?
Note This is not Spring Data JPA. Its Spring Data JDBC.
Edit
Looking more into it, the exception is from h2 database lib.
Caused by: org.h2.jdbc.JdbcSQLException: Column "orderid" not found [42122-190]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:345)
at org.h2.message.DbException.get(DbException.java:179)
at org.h2.message.DbException.get(DbException.java:155)
at org.h2.jdbc.JdbcResultSet.getColumnIndex(JdbcResultSet.java:3129)
at org.h2.jdbc.JdbcResultSet.get(JdbcResultSet.java:3217)
at org.h2.jdbc.JdbcResultSet.getObject(JdbcResultSet.java:522)
at com.zaxxer.hikari.pool.HikariProxyResultSet.getObject(HikariProxyResultSet.java)
at org.springframework.data.jdbc.core.EntityRowMapper.readFrom(EntityRowMapper.java:127)
You can't at least right now.
There are three solutions to this, two of which you already pointed out:
extend your select statement with , NULL as <column-name> for all the missing columns.
I'm not sure if
But this will still serialize the entire object with null values.
means that this isn't working for you in some way.
specify a RowMapper.
You could use a class containing exactly the fields returned by the query. It could even have getters for the other columns if you want an interface implemented by both your normal entity and the partial entity.
You write:
But the whole point of spring data JDBC is to avoid the tight coupling between pojo's data model and database schema.
This is not quite right.
An important goal of Spring Data JDBC is to not have a run time connection between entities and table rows.
This would require proxies or similar and brings a lot of complexity.
But the structural mapping between entities and table is probably going to be stronger (and certainly is right now) since all the variants of mappings available in JPA bring complexity.
And the main goal in Spring Data JDBC is to be conceptually simpler than JPA.
You also ask
Why not the EntityRowMapper is just mapping NULL to the properties which are not part of the query?
I'm not sure if I actively thought about it when I coded it but I don't like the idea of defaulting to NULL because this would make it easy to accidentally not load a column because you have a typo in an alias.
But I'm not against alternative solutions.
If you have an idea please create a feature request.
Okay. I am getting a little confused here...
Lets say I have a class called User.
class User {
// all variables
// all getters and setters
}
Now, I use JSR 303 validation and put #NotNull, #Range, etc here for the variables.
I use this as Form / Command object. Meaning, when a form a submitted, the values are validated and BindingResult gives me errors.
Should this be used as in Entity Object for Hibernate as well? (If so, I need to add other Hibernate annotations like #Entity, #Id, #Column, etc on top of Validation annotations)
When we load the data from Database, do these validations kick in as well? (If yes, what if the data is already existing, and do not confirm to the validations?)
Where do we normally write business validations, like for example, country exists or not in the database, xyz value exists in a different table, etc?
Questions arise here as well:
- User form may not have all the fields that exist in the User class
- Database table User may have more fields or less fields than User class
- Form may have fields from different objects as well, say User and and Order.
How do we handle these?
Trying to wrap my mind around it
No you shouldn't mix entities objects and values objects. Entities objects are for DB mapping and values objects are used in the presentation layer.
To validate an object annoted, you need to use a Validator (commonly used with a DataBinder. Spring validation)
Is it DB constraints or backend validation?
For your last question, that's one of the reason to have 2 differentes objects for your presentation layer and your persistence layer. This way values objects can match what is displayed or input by the user (Form).
Entity object is an object of our plain old java class(POJO) Model/Business class, which needs to be persisted in a database using Hibernate, while Value Type object is an object of another class but it is stored as a part of Entity object within a database table.
#Embeddable
#Data
#AllArgsConstructor
public class Address{
private String country;
private String city;
private String street1;
private String street2;
private postalCode;
}
#Entity
#Data
#AllArgsConstructor
public class Person{
#Id
private Long id;
private String firstName;
private String lastName;
private ing age;
private Address address;
}
}
So after running this code in spring and hibernate project you will see Person table in database is created with it's attributes and Address class attributes.
For more information, I suggest reading this:
[https://www.decodejava.com/hibernate-value-type-object.htm][1]