Wiki source code of WebObjects and Squeryl
Version 99.1 by Ravi Mendis on 2010/11/10 05:38
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81.1 | 1 | = Squeryl ~= //SQL-like// DSL for Scala = |
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54.1 | 2 | |
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85.1 | 3 | Advantages of Squeryl over EOF: |
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54.1 | 4 | |
| 5 | * Concurrent | ||
| 6 | ** Spawns multiple database connections | ||
| 7 | ** Issues database transactions concurrently | ||
| 8 | * Scala Actor compatible | ||
| 9 | ** Immutable object model/graph | ||
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81.1 | 10 | * Strongly-typed |
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54.1 | 11 | ** Better suited for database/business "logic". |
| 12 | E.g: Exploits the compiler and IDE to catch exceptions at compile time rather than at run-time. | ||
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85.1 | 13 | * Uses Scala (functional) collection classes |
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54.1 | 14 | |
| 15 | = Migrating EOF -> Squeryl = | ||
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95.1 | 17 | In contrast to EOF Squeryl maintains its ORM information programmatically - in the classes itself and collectively in a ##schema##. In keeping with the strongly-typed philosophy of Scala, Squeryl has no dynamic component like EOF (i.e an EO model file). |
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54.1 | 18 | |
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85.1 | 19 | EOF has the ability to generate classes in Java (and in Objective-C prior to WebObjects 4.5) as enforcing type has become customary in enterprise environments. We may exploit this feature of EOF to generate a Squeryl schema. |
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54.1 | 20 | |
| 21 | === Preparing your EO model === | ||
| 22 | |||
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85.1 | 23 | * Make sure **all** EO entities have a class name (including abstract many-To-many "join" tables). There's no support for entities marked as ##EOGenericRecord##. |
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91.1 | 24 | * Mark the abstract many-To-Many join entities as ##Abstract##. |
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99.1 | 25 | * (Temporary) Ensure all the model entities are in the same package. i.e the package is exclusive to the model. |
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54.1 | 26 | |
| 27 | === Generating the Squeryl Schema === | ||
| 28 | |||
| 29 | 1. Create a .eogen file for your EO model as normal. Only set the ##File Names## extension to "scala". | ||
| 30 | 1. Use the Squeryl EO Templates: | ||
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| 32 | * | ||
| 33 | ** Entity.eotemplate [[template>>WOL:Squeryl _Entity.eotemplate]] | ||
| 34 | ** Entity.eotemplate [[template>>WOL:Squeryl Entity.eotemplate]] | ||
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| 36 | {{note title="Note"}} | ||
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| 38 | Any custom business "logic" will have to be manually re-written in Scala | ||
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| 40 | {{/note}} | ||
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99.1 | 41 | |
| 42 | == Differences Between a Squeryl Schema and EOF Classes == | ||
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| 44 | * Optional attributes (i.e those that ##allowsNull##) are typed as ##Option[[T]]## | ||
| 45 | * Relationships that are not mandatory (i.e optional relationships) are also typed as ##Option[[T]]## | ||
| 46 | * ToMany relationships are represented as a Squeryl iterable (collection class) as opposed to a ##NSArray##. |