Posts - Page 120 (page 120)
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7 min readIn Hibernate, you can get the changed properties before updating an object by using the Session interface and the DirtyChecker interface.First, you need to obtain the Session object by calling sessionFactory.getCurrentSession(). Then, retrieve the DirtyChecker instance by calling session.getSessionFactory().getMetamodel().entityPersister(entityClass).getEntityTuplizer().getEntityMetamodel().getBytecodeEnhancementMetadata().getDirtyTracker().
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3 min readTo select two columns with one as the maximum value in Oracle, you can use a subquery to find the maximum value in one column and then join it with the original table based on that maximum value using a WHERE clause. This way, you can retrieve the corresponding values from the other column in the same row as the maximum value in the first column.[rating:dc3bb8f1-bf14-46f8-a39b-16fc925c6a8c]How to handle multiple max values in Oracle.
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6 min readTo optimize the hibernate execution time, you can follow several strategies. First, make sure to properly configure and tune your database connection pool to efficiently manage connections to the database. This can help reduce the time spent on establishing and closing connections.Additionally, configure hibernate caching to store frequently accessed data in memory, reducing the need for frequent database queries. Use second-level caching for entity and query caching to improve performance.
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5 min readTo trim the text in different columns in Oracle, you can use the TRIM function. This function allows you to remove specified characters from the beginning or end of a string. You can specify the characters you want to remove as the second argument in the TRIM function.
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7 min readIn Hibernate, a composite foreign key mapping refers to mapping a composite primary key from one table to a composite foreign key in another table. To define a composite foreign key mapping in Hibernate, you need to use the @ManyToOne annotation along with @JoinColumns annotation on the entity class that represents the many side of the relationship. The @JoinColumns annotation allows you to specify multiple columns that make up the composite foreign key.
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7 min readTo select the value from an XML field in an Oracle query, you can use the XMLType function to convert the XML data into a format that allows for querying. Once the XML data is converted, you can then use XPath expressions to navigate through the XML structure and retrieve the desired values. By using the XMLTable function, you can extract specific values from the XML field and include them in your query results.
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5 min readTo get the size of the Hibernate connection pool, you can look into the configuration settings of your Hibernate framework. The size of the connection pool is typically defined in the Hibernate configuration file, which is usually named hibernate.cfg.xml or hibernate.properties.In the configuration file, you will find a property that specifies the maximum number of connections that can be created in the pool. This property is often named "hibernate.c3p0.
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7 min readTo safely reset an Oracle sequence, you can follow these steps:Query the current value of the sequence using the following SQL statement: SELECT your_sequence.NEXTVAL FROM DUAL; Note down the current value returned by the query.
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10 min readTo handle JSON values from a native query in Hibernate, you can define a custom data type for mapping JSON values in your entity class. You can use the JsonNode type from the Jackson library to represent the JSON values.When executing a native query that returns JSON values, you can specify the return type as JsonNode in the createNativeQuery method call. You can then process the JSON values using the methods provided by the JsonNode class.
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5 min readIn Oracle SQL, the JOIN operator is used to combine rows from two or more tables based on a related column between them. There are different types of joins such as INNER JOIN, LEFT JOIN (or LEFT OUTER JOIN), RIGHT JOIN (or RIGHT OUTER JOIN), and FULL JOIN (or FULL OUTER JOIN).To use the JOIN operator in Oracle SQL, you need to specify the tables you want to join followed by the specific type of join and the condition on which the tables should be joined.
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4 min readTo get specific columns from a Hibernate join, you can use the Projections class from the Hibernate Criteria API. By using Projections, you can specify the columns that you want to retrieve from the joined entities. This allows you to avoid retrieving all columns from the joined tables and only get the data that you actually need. Additionally, you can also use aliases to give meaningful names to the columns that you retrieve, making it easier to work with the results.
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4 min readTo set configuration using application.properties in hibernate, you can specify the configuration properties directly in the application.properties file in your Spring Boot project. You can configure properties such as the database URL, username, password, dialect, show_sql, and many others by prefixing them with spring.jpa.hibernate in the application.properties file. For example, you can set the database URL by adding spring.jpa.hibernate.jdbc.