2016-01-28 23:31:35 +00:00
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module DB
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2016-01-31 22:40:02 +00:00
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# The response of a query performed on a `Database`.
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#
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# See `DB` for a complete sample.
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#
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# Each `#read` call consumes the result and moves to the next column.
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#
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# ### Note to implementors
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#
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# 1. Override `#move_next` to move to the next row.
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# 2. Override `#read?(t)` for all `t` in `DB::TYPES`.
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# 3. (Optional) Override `#read(t)` for all `t` in `DB::TYPES`.
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# 4. Override `#column_count`, `#column_name`.
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# 5. Override `#column_type`. It must return a type in `DB::TYPES`.
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2016-01-28 23:31:35 +00:00
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abstract class ResultSet
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2016-02-03 20:10:03 +00:00
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include Disposable
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2016-02-03 21:46:37 +00:00
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# :nodoc:
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2016-01-28 23:31:35 +00:00
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getter statement
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2016-02-04 00:51:32 +00:00
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def initialize(@statement : DB::Statement)
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2016-01-28 23:31:35 +00:00
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end
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2016-02-03 22:30:51 +00:00
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protected def do_close
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2016-02-04 00:28:53 +00:00
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statement.release_connection
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2016-02-03 22:30:51 +00:00
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end
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2016-02-02 00:55:30 +00:00
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# TODO add_next_result_set : Bool
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2016-01-31 22:40:02 +00:00
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# Iterates over all the rows
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2016-01-28 23:51:03 +00:00
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def each
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2016-01-29 19:13:01 +00:00
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while move_next
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2016-01-28 23:51:03 +00:00
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yield
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end
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end
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2016-01-31 22:40:02 +00:00
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# Move the next row in the result.
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# Return `false` if no more rows are available.
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# See `#each`
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2016-01-29 19:13:01 +00:00
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abstract def move_next : Bool
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2016-01-28 23:31:35 +00:00
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2016-01-30 22:46:43 +00:00
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# TODO def empty? : Bool, handle internally with move_next (?)
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2016-01-31 22:40:02 +00:00
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# Returns the number of columns in the result
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2016-01-30 00:57:00 +00:00
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abstract def column_count : Int32
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2016-01-31 22:40:02 +00:00
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# Returns the name of the column in `index` 0-based position.
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2016-01-30 00:57:00 +00:00
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abstract def column_name(index : Int32) : String
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2016-01-31 22:40:02 +00:00
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# Returns the type of the column in `index` 0-based position.
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# The result is one of `DB::TYPES`.
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2016-01-30 22:46:43 +00:00
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abstract def column_type(index : Int32)
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2016-01-30 00:57:00 +00:00
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2016-01-28 23:31:35 +00:00
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# list datatypes that must be supported form the driver
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2016-01-29 19:13:01 +00:00
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# users will call read(String) or read?(String) for nillables
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2016-01-31 22:40:02 +00:00
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2016-01-29 19:13:01 +00:00
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{% for t in DB::TYPES %}
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2016-01-31 22:40:02 +00:00
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# Reads the next column as a nillable {{t}}.
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2016-01-29 19:13:01 +00:00
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abstract def read?(t : {{t}}.class) : {{t}}?
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2016-01-31 22:40:02 +00:00
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# Reads the next column as a {{t}}.
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2016-01-28 23:31:35 +00:00
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def read(t : {{t}}.class) : {{t}}
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2016-01-29 19:13:01 +00:00
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read?({{t}}).not_nil!
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2016-01-28 23:31:35 +00:00
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end
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{% end %}
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2016-02-02 00:55:30 +00:00
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# def read_blob
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# yield ... io ....
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# end
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# def read_text
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# yield ... io ....
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# end
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2016-01-28 23:31:35 +00:00
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end
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end
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