36 lines
1.2 KiB
Plaintext
36 lines
1.2 KiB
Plaintext
== Spring Data R2DBC - Query-by-Example (QBE) example
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This project contains samples of Query-by-Example of Spring Data R2DBC.
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=== Support for Query-by-Example
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Query by Example (QBE) is a user-friendly querying technique with a simple interface.
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It allows dynamic query creation and does not require to write queries containing field names.
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In fact, Query by Example does not require to write queries using SQL at all.
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An `Example` takes a data object (usually the entity object or a subtype of it) and a specification how to match properties.
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You can use Query by Example with Repositories.
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[source,java]
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----
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interface PersonRepository extends ReactiveCrudRepository<Person, Long>, ReactiveQueryByExampleExecutor<Person> {
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}
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----
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[source,java]
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----
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Example<Person> example = Example.of(new Person("Jon", "Snow"));
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repo.findAll(example);
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ExampleMatcher matcher = ExampleMatcher.matching().
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.withMatcher("firstname", endsWith())
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.withMatcher("lastname", startsWith().ignoreCase());
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Example<Person> example = Example.of(new Person("Jon", "Snow"), matcher);
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repo.count(example);
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----
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This example contains shows the usage with `PersonRepositoryIntegrationTests`.
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