126 lines
3.6 KiB
Ruby
126 lines
3.6 KiB
Ruby
require 'sqlite3/constants'
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require 'sqlite3/errors'
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module SQLite3
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# The ResultSet object encapsulates the enumerability of a query's output.
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# It is a simple cursor over the data that the query returns. It will
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# very rarely (if ever) be instantiated directly. Instead, client's should
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# obtain a ResultSet instance via Statement#execute.
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class ResultSet
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include Enumerable
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# The class of which we return an object in case we want an Array as
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# result. (ArrayFields is installed.)
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class ArrayWithTypes < Array
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attr_accessor :types
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end
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# The class of which we return an object in case we want an Array as
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# result. (ArrayFields is not installed.)
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class ArrayWithTypesAndFields < Array
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attr_accessor :types
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attr_accessor :fields
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end
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# The class of which we return an object in case we want a Hash as
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# result.
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class HashWithTypes < Hash
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attr_accessor :types
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end
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# Create a new ResultSet attached to the given database, using the
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# given sql text.
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def initialize db, stmt
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@db = db
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@stmt = stmt
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end
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# Reset the cursor, so that a result set which has reached end-of-file
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# can be rewound and reiterated.
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def reset( *bind_params )
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@stmt.reset!
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@stmt.bind_params( *bind_params )
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@eof = false
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end
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# Query whether the cursor has reached the end of the result set or not.
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def eof?
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@stmt.done?
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end
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# Obtain the next row from the cursor. If there are no more rows to be
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# had, this will return +nil+. If type translation is active on the
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# corresponding database, the values in the row will be translated
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# according to their types.
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#
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# The returned value will be an array, unless Database#results_as_hash has
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# been set to +true+, in which case the returned value will be a hash.
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#
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# For arrays, the column names are accessible via the +fields+ property,
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# and the column types are accessible via the +types+ property.
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#
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# For hashes, the column names are the keys of the hash, and the column
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# types are accessible via the +types+ property.
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def next
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row = @stmt.step
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return nil if @stmt.done?
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if @db.type_translation
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row = @stmt.types.zip(row).map do |type, value|
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@db.translator.translate( type, value )
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end
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end
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if @db.results_as_hash
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new_row = HashWithTypes[*@stmt.columns.zip(row).flatten]
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row.each_with_index { |value,idx|
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new_row[idx] = value
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}
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row = new_row
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else
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if row.respond_to?(:fields)
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row = ArrayWithTypes.new(row)
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else
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row = ArrayWithTypesAndFields.new(row)
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end
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row.fields = @stmt.columns
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end
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row.types = @stmt.types
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row
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end
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# Required by the Enumerable mixin. Provides an internal iterator over the
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# rows of the result set.
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def each( &block )
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while node = self.next
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yield node
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end
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end
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# Closes the statement that spawned this result set.
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# <em>Use with caution!</em> Closing a result set will automatically
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# close any other result sets that were spawned from the same statement.
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def close
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@stmt.close
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end
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# Queries whether the underlying statement has been closed or not.
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def closed?
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@stmt.closed?
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end
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# Returns the types of the columns returned by this result set.
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def types
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@stmt.types
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end
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# Returns the names of the columns returned by this result set.
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def columns
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@stmt.columns
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end
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end
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end
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