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codecov Apache License V.2 Maven Central

jasync-sql-extensions

jasync-sql-extensions is a simple Extension of jasync-sql. The current Features include:

  • Named argument binding
    • List binding
    • Bean binding
    • Json binding
  • Data class mapping
    • Json mapping
    • Custom mapper support
    • WIP: 1 to N, N to N and 1 to 1 support via dsl

Getting Started

jasync-sql-extensions is based upon extension functions. So create a query using named bindings start like this:

    connection.sendPreparedStatement(
        "SELECT :bert.number, :bert.nabla, :carol.id, :carol.name",
        mapOf(
            "bert" to Bert(
                number = 42, 
                nabla = "bar"
            ),
            "carol" to Carol(
                id = 24,
                name = "Homer"
            ) 
        )
    )

To map a result set, use the mapTo<>() extension.

  resultSet.mapTo<Carol>()

This will map the corresponding columns into objects.

Use in your project

Add this to your build.gradle file

  compile group: "com.github.28Smiles", name: "jasync-sql-extensions", version: "0.3.1"

Speed

To improve the speed of mapping columns into objects, before mapping the bean is analysed and the most efficient code will be syntesised using ASM. This way the mapTo<>() implementation, in most cases, outperforms mapping code created by the kotlin compiler, since some null checks have been ommited. The MappingBenchmark, mapping a result set of 500000 rows shows the following run times:

      Manual mapping of the select took: 61 ms
      Reflection mapping of the select took: 233 ms
      Cold ASM mapping of the select took: 86 ms
      Hot ASM mapping of the select took: 51 ms

Manual mapping refers to a standard kotlin implementation. Reflection mapping refers to a mapping using kotlin reflection. Cold ASM mapping refers to code being synthesized and then executed. Hot ASM mapping refers code being cached and executed. Using the SmallMappingBenchmark, mapping 30 beans, we get a impression of the initial overhead:

      Manual mapping of the select took: 1120 us
      Reflection mapping of the select took: 55562 us
      Cold ASM mapping of the select took: 31021 us
      Hot ASM mapping of the select took: 147 us

Stabillity

This libary is tested, but it most certainly contains bugs and has several limitations, use with caution.