[#1773] Add a new jOOQ-Scala project and jooq-scala artefactId, to
contain jOOQ extensions in the Scala language - Updated manual
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Lukas Eder
parent
fe149dad41
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7df7f70865
@ -58,7 +58,7 @@ object Test {
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T_BOOK.TITLE || " abc" || " xy")
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from T_BOOK
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leftOuterJoin (
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f select ( x.ID, x.YEAR_OF_BIRTH)
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f select (x.ID, x.YEAR_OF_BIRTH)
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from x
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limit 1
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asTable x.getName()
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@ -180,6 +180,11 @@
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<xsl:value-of select="text()"/>
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</pre>
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</xsl:when>
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<xsl:when test="name(.) = 'scala'">
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<pre class="prettyprint lang-scala">
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<xsl:value-of select="text()"/>
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</pre>
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</xsl:when>
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<xsl:when test="name(.) = 'sql'">
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<pre class="prettyprint lang-sql">
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<xsl:value-of select="text()"/>
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@ -885,7 +885,73 @@ public class Main {
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<section id="jooq-and-scala">
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<title>jOOQ and Scala</title>
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<content></content>
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<content>
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<p>
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As any other library, jOOQ can be easily used in Scala, taking advantage of the many Scala language features such as for example:
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</p>
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<ul>
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<li>Optional "." to dereference methods from expressions</li>
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<li>Optional "(" and ")" to delimit method argument lists</li>
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<li>Optioanl ";" at the end of a Scala statement</li>
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<li>Type inference using "var" and "val" keywords</li>
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</ul>
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<p>
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But jOOQ also leverages other useful Scala features, such as
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</p>
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<ul>
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<li>implicit defs for operator overloading</li>
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<li>Scala Macros (soon to come)</li>
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</ul>
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<p>
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A short example jOOQ application in Scala might look like this:
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</p>
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<scala><![CDATA[
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import collection.JavaConversions._ // Import implicit defs for iteration over org.jooq.Result
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//
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import java.sql.DriverManager //
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//
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import org.jooq._ //
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import org.jooq.impl._ //
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import org.jooq.impl.Factory._ //
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import org.jooq.scala.example.h2.Tables._ //
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import org.jooq.scala.Conversions._ // Import implicit defs for overloaded jOOQ/SQL operators
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//
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object Test { //
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def main(args: Array[String]): Unit = { //
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val c = DriverManager.getConnection("jdbc:h2:~/test", "sa", ""); // Standard JDBC connection
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val f = new Factory(c, SQLDialect.H2); //
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val x = T_AUTHOR as "x" // SQL-esque table aliasing
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//
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for (r <- f // Iteration over Result. "r" is an org.jooq.Record
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select ( //
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T_BOOK.ID * T_BOOK.AUTHOR_ID, // Using the overloaded "*" operator
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T_BOOK.ID + T_BOOK.AUTHOR_ID * 3 + 4, // Using the overloaded "+" operator
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T_BOOK.TITLE || " abc" || " xy" // Using the overloaded "||" operator
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) //
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from T_BOOK // No need to use parentheses or "." here
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leftOuterJoin ( //
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f select (x.ID, x.YEAR_OF_BIRTH) // Dereference fields from aliased table
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from x //
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limit 1 //
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asTable x.getName() //
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) //
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on T_BOOK.AUTHOR_ID === x.ID // Using the overloaded "===" operator
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where (T_BOOK.ID <> 2) // Using the olerloaded "<>" operator
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or (T_BOOK.TITLE in ("O Alquimista", "Brida")) // Neat IN predicate expression
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fetch //
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) { //
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println(r) //
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} //
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} //
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}]]></scala>
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<p>
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For more details about jOOQ's Scala integration, please refer to the manual's section about <reference id="scala-sql-building" title="SQL building with Scala"/>.
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</p>
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</content>
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</section>
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<section id="dependencies">
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@ -5200,7 +5266,135 @@ create.attach(select);]]></java>
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<section id="scala-sql-building">
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<title>SQL building in Scala</title>
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<content></content>
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<content>
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<p>
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jOOQ-Scala is a maven module used for leveraging some advanced Scala features for those users that wish to use jOOQ with Scala.
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</p>
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<h3>Using Scala's implicit defs to allow for operator overloading</h3>
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<p>
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The most obvious Scala feature to use in jOOQ are implicit defs for implicit conversions in order to enhance the <reference class="org.jooq.Field"/> type with SQL-esque operators.
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</p>
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<p>
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The following depicts a trait which wraps all fields:
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</p>
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<scala><![CDATA[/**
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* A Scala-esque representation of {@link org.jooq.Field}, adding overloaded
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* operators for common jOOQ operations to arbitrary fields
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*/
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trait SAnyField[T] extends Field[T] {
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// String operations
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// -----------------
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def ||(value : String) : Field[String]
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def ||(value : Field[_]) : Field[String]
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// Comparison predicates
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// ---------------------
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def ===(value : T) : Condition
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def ===(value : Field[T]) : Condition
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def !==(value : T) : Condition
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def !==(value : Field[T]) : Condition
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def <>(value : T) : Condition
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def <>(value : Field[T]) : Condition
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def >(value : T) : Condition
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def >(value : Field[T]) : Condition
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def >=(value : T) : Condition
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def >=(value : Field[T]) : Condition
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def <(value : T) : Condition
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def <(value : Field[T]) : Condition
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def <=(value : T) : Condition
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def <=(value : Field[T]) : Condition
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def <=>(value : T) : Condition
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def <=>(value : Field[T]) : Condition
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}]]></scala>
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<p>
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The following depicts a trait which wraps numeric fields:
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</p>
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<scala><![CDATA[/**
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* A Scala-esque representation of {@link org.jooq.Field}, adding overloaded
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* operators for common jOOQ operations to numeric fields
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*/
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trait SNumberField[T <: Number] extends SAnyField[T] {
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// Arithmetic operations
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// ---------------------
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def unary_- : Field[T]
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def +(value : Number) : Field[T]
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def +(value : Field[_ <: Number]) : Field[T]
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def -(value : Number) : Field[T]
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def -(value : Field[_ <: Number]) : Field[T]
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def *(value : Number) : Field[T]
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def *(value : Field[_ <: Number]) : Field[T]
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def /(value : Number) : Field[T]
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def /(value : Field[_ <: Number]) : Field[T]
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def %(value : Number) : Field[T]
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def %(value : Field[_ <: Number]) : Field[T]
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// Bitwise operations
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// ------------------
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def unary_~ : Field[T]
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def &(value : T) : Field[T]
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def &(value : Field[T]) : Field[T]
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def |(value : T) : Field[T]
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def |(value : Field[T]) : Field[T]
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def ^(value : T) : Field[T]
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def ^(value : Field[T]) : Field[T]
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def <<(value : T) : Field[T]
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def <<(value : Field[T]) : Field[T]
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def >>(value : T) : Field[T]
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def >>(value : Field[T]) : Field[T]
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}]]></scala>
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<p>
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An example query using such overloaded operators would then look like this:
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</p>
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<scala><![CDATA[select (
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T_BOOK.ID * T_BOOK.AUTHOR_ID,
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T_BOOK.ID + T_BOOK.AUTHOR_ID * 3 + 4,
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T_BOOK.TITLE || " abc" || " xy")
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from T_BOOK
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leftOuterJoin (
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f select (x.ID, x.YEAR_OF_BIRTH)
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from x
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limit 1
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asTable x.getName()
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)
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on T_BOOK.AUTHOR_ID === x.ID
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where (T_BOOK.ID <> 2)
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or (T_BOOK.TITLE in ("O Alquimista", "Brida"))
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fetch]]></scala>
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<h3>Scala 2.10 Macros</h3>
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<p>
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This feature is still being experimented with. With Scala Macros, it might be possible to inline a true SQL dialect into the Scala syntax, backed by the jOOQ API. Stay tuned!
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</p>
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</content>
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</section>
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</sections>
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</section>
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@ -7419,11 +7613,6 @@ Finishing : Total: 4.814ms, +3.375ms
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</p>
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</content>
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</section>
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<section id="scala-sql-execution">
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<title>SQL execution in Scala</title>
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<content></content>
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</section>
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</sections>
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</section>
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@ -517,7 +517,7 @@
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</fo:table>
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</xsl:template>
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<xsl:template match="java | sql | xml | text | config" mode="content">
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<xsl:template match="java | scala | sql | xml | text | config" mode="content">
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<fo:block xsl:use-attribute-sets="pre">
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<xsl:apply-templates mode="content" />
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</fo:block>
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