forked from Baguette/dodb.cr
70 lines
1.9 KiB
Markdown
70 lines
1.9 KiB
Markdown
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# dodb.cr
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DODB stands for Document Oriented DataBase.
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# Installation
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Add the following to your `shard.yml`.
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You may want to add version informations to avoid unexpected breakages.
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```yaml
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dependencies:
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dodb:
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git: https://git.karchnu.fr/WeirdOS/dodb.cr
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```
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# Usage
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```crystal
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db = DODB::DataBase(Thing).new "path/to/storage/directory"
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db << Thing.new
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db.each do |thing|
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pp! thing
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end
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```
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```crystal
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# First, we define the thing we’ll want to store.
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# It *has* to be serializable through JSON, as everything in DODB is stored in JSON.
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class Thing
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include JSON::Serializable
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property id : String
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property category : String # In this example we’ll assume a unique category.
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property tags : Array(String)
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def initialize(@id, @category, @tags)
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end
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end
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# Then we create our database.
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things = DODB::DataBase(Thing).new "path/to/storage/directory"
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# Then we define indices to it. There are several ways to index things in DODB.
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# Indices are the simplest way to do so. They represent attributes that are
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# unique in the collection. They are “1-1” associations.
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things_by_id = things.new_index "id", &.id
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# Partitions represent attributes that are shared in the collection. They can
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# be used to obtain entries grouped by value. They are “1-n” associations.
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things_by_category = things.new_partition "category", &.category
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# Tags are “n-n associations”.
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things_by_tags = things.new_tags "tags", &.tags
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# At this point, we can add or try to access data.
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things << Thing.new "one", "word", ["number"] of String
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things << Thing.new "two", "word", ["number"] of String
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things << Thing.new "three", "word", ["number"] of String
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things << Thing.new "hello, world", "sentence", [] of String
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things_by_tags.get "number" # Will return an array of three things ("one", "two", "three").
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things_by_category.get "sentence" # Will return an array of one thing ("hello, world")
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things_by_id.get "one" # Will return a single thing ("one")
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```
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