Changes for page WebObjects and Squeryl
Last modified by Ravi Mendis on 2011/04/01 11:14
From version 56.1
edited by Ravi Mendis
on 2011/02/27 23:20
on 2011/02/27 23:20
Change comment:
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To version 54.1
edited by Ravi Mendis
on 2011/03/31 23:36
on 2011/03/31 23:36
Change comment:
There is no comment for this version
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... ... @@ -1,4 +1,4 @@ 1 -= Squeryl ~= //SQL-like// DSL forScala =1 += Squeryl ~= //SQL-like// DSL in Scala = 2 2 3 3 Advantages of [[Squeryl>>http://squeryl.org/]] over EOF: 4 4 ... ... @@ -7,11 +7,11 @@ 7 7 ** Issues database transactions concurrently 8 8 * Scala Actor compatible 9 9 ** Immutable object model/graph 10 -** Fine-grainedtransaction control11 -* Strongly-typed10 +** Explicit transaction control 11 +* Type Safety 12 12 ** Better suited for database/business "logic". 13 13 E.g: Exploits the compiler and IDE to catch exceptions at compile time rather than at run-time. 14 -* Uses Scala collectionclasses14 +* Uses Scala Collections 15 15 16 16 = Migrating EOF -> Squeryl = 17 17 ... ... @@ -45,3 +45,38 @@ 45 45 * Optional attributes (i.e those that ##allowsNull##) are typed as ##OptionT## 46 46 * To one relationships that are not mandatory (i.e optional relationships) are also typed as ##OptionT## 47 47 * To many relationships are represented as a Squeryl iterable (collection class) as opposed to a ##NSArray##. 48 + 49 +=== Use of Scala Collections === 50 + 51 +===== 1. Filtering ===== 52 + 53 +Instead of using EOQualifiers to filter EOs dynamically, you can apply the type safe filter in Scala: 54 + 55 +{{code}} 56 + 57 +def activeFiles = files.filter(_.active == true) 58 + 59 +{{/code}} 60 + 61 +===== 2. Iteration ===== 62 + 63 +Functional language iteration that's become increasingly popular can be used: 64 + 65 +{{code}} 66 + 67 +activeFiles.foreach(f => { 68 + ... 69 +}) 70 + 71 +{{/code}} 72 + 73 +===== 3. For-Comprehensions ===== 74 + 75 +{{code}} 76 + 77 + 78 +Here's just an example use of sequence comprehension: 79 + 80 +def activeFiles = for (file <- files if file.active == true) yield f 81 + 82 +{{/code}}