Configuration Koan
Learn:
- how to configure a MyBatis config file, including a shared properties that will used by the MyBatis config file
- how to wire up your Java code to use the MyBatis config file
- how to create a SqlSessionFactory
Xml mapper file
Learn:
- how to reference a mapper file from a MyBatis config file
- how to set up a SQL mapping in a mapper file
- how to create a
SqlSession - how to call the SQL mapping and get data from the database via MyBatis
- the basic types of datastructures that MyBatis can return and how to specify them
Domain objects
Learn:
- how to create a mapper xml file that returns a domain object, rather than a generic data structure
- how to return a list or map of domain objects from a mapped SQL query
- how to set up a TypeAlias in the MyBatis config file
Domain objects, using underscore to camelCase mapping
Learn:
- how to tell MyBatis to convert underscores to camelCase to auto-map database column names to object property names
Mapper interface
Learn:
- how to create and use a Java Mapper interface to do the same type of queries in the previous koans
Multiple Arguments and RowBounds
Learn:
- how to create and use a Java Mapper interface to do the same type of queries in the previous koans
- how to return a simple numeric value from a mapped SQL query
- how to pass in multiple arguments to a mapped query (including using annotations)
- how to use a MyBatis RowBounds object to limit the number of results returned
Annotation driven mappings
Learn:
- how to do annotation driven mappings
- how to specify a mapper in the config file when you don't have an XML mapping file
Updates, inserts and deletes
Learn:
- how to do updates, inserts and deletes
- in xml mapping files
- annotation driven in Java Mapper interfaces
- how to use the
selectKeyfeature of MyBatis to dynamically create a new key for a domain object being inserted into the database - the effect of calling
rollback,commitor neither on the session object when executing DML statements via MyBatis
<sql> and dynamic string substitution
Learn:
- how to use the
<sql>MyBatis element to keep your SQL DRY ("don't repeat yourself") - how to do dynamic string substitution in sections of SQL that are not bound variables to PreparedStatements
ResultMaps, part 1
Learn:
- how to use a ResultMap for a single table query
- how to use a ResultMap for a multiple table query, using the "association" feature
- how to use ResultMaps as part of a "nested select" (the N+1 approach)
ResultMaps, part 2
Learn:
- how to use a ResultMap for a multiple table query, using the "collection" feature
TypeHandlers
Learn:
- How to use a MyBatis TypeHandler in order to set a domain specific object type as a field in a mapped object
- Learn to set a TypeHandler for all object type (for any query that uses it)
- Learn to set a TypeHandler for a specify field/column of a specify mapped query
MyBatis and Immutable Objects, part 1
Learn:
- How to use a MyBatis with immutable objects that have no setter fields
- Learn to set a TypeHandler for all object type (for any query that uses it)
- Learn to set a TypeHandler for a specify field/column of a specify mapped query
- How to use multiple mapper files that reference each other
MyBatis and Immutable Objects, part 2
Learn:
- How to use a MyBatis with immutable objects that have no setter fields and without having to directly map to long constructor param lists by implementing MyBatis' ObjectFactory
- How to use a ResultHandler to do additional things with the objects created by MyBatis (or your ObjectFactory), such as filtering what results are returned
Database inserts, revisited
Learn:
- How to use a TypeHandler to insert into a table where its mapped domain object depends on other domain objects
- How to insert null values into a nullable columns in the database
Calling stored procedures via XML mappings
Learn:
- How to call a stored procedure and stored functions from MyBatis using XML mapping
- How to handle both IN and OUT parameter types
Calling stored procedures via Java annotation mappings
Learn:
- How to call a stored procedure and stored functions from MyBatis using Java annotations
Statement Builders
Learn:
- How to use the MyBatis SelectBuilder "DSL" to generate SQL statements
- How to use the MyBatis SqlBuilder "DSL" to generate SQL insert, update and delete statements
- How to use the MyBatis SqlBuilder "DSL" to generate compound SQL (subselects)
Using the Null object pattern with MyBatis
Learn:
- How to create a Null object when a null value is returned from a database query
Prepared vs. non-prepared statements in MyBatis
Learn:
- The difference between the #{} variable notation and ${}
- How to use the ${} notation with a domain object
- How to deal with an enum type in your sakila database (if using PostgreSQL or MySQL)
Dynamic SQL
Learn:
- How to use the
<if>conditional to build a SQL statement - How to most effectively build a compound where and set clause using the
<where>and<set>features - How to loop over lists when building SQL using
<foreach>
(Slightly) More Complicated Mappings
Learn:
- How to do an insert that takes two domain objects and extract the appropriate ids from them in the MyBatis mapping
- How to map a three table join
Using Java Enums with MyBatis
Learn:
- How to map a Java Enum to the result of a database query
- How to map a Java Enum to a database DML (insert/update/delete)