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require "sqlite3/constants"
require "sqlite3/errors"
module SQLite3
# The ResultSet object encapsulates the enumerability of a query's output.
# It is a simple cursor over the data that the query returns. It will
# very rarely (if ever) be instantiated directly. Instead, clients should
# obtain a ResultSet instance via Statement#execute.
class ResultSet
include Enumerable
# Create a new ResultSet attached to the given database, using the
# given sql text.
def initialize db, stmt
@db = db
@stmt = stmt
end
# Reset the cursor, so that a result set which has reached end-of-file
# can be rewound and reiterated.
def reset(*bind_params)
@stmt.reset!
@stmt.bind_params(*bind_params)
end
# Query whether the cursor has reached the end of the result set or not.
def eof?
@stmt.done?
end
# Obtain the next row from the cursor. If there are no more rows to be
# had, this will return +nil+.
#
# The returned value will be an array, unless Database#results_as_hash has
# been set to +true+, in which case the returned value will be a hash.
#
# For arrays, the column names are accessible via the +fields+ property,
# and the column types are accessible via the +types+ property.
#
# For hashes, the column names are the keys of the hash, and the column
# types are accessible via the +types+ property.
def next
@stmt.step
end
# Required by the Enumerable mixin. Provides an internal iterator over the
# rows of the result set.
def each
while (node = self.next)
yield node
end
end
# Provides an internal iterator over the rows of the result set where
# each row is yielded as a hash.
def each_hash
while (node = next_hash)
yield node
end
end
# Closes the statement that spawned this result set.
# <em>Use with caution!</em> Closing a result set will automatically
# close any other result sets that were spawned from the same statement.
def close
@stmt.close
end
# Queries whether the underlying statement has been closed or not.
def closed?
@stmt.closed?
end
# Returns the types of the columns returned by this result set.
def types
@stmt.types
end
# Returns the names of the columns returned by this result set.
def columns
@stmt.columns
end
# Return the next row as a hash
def next_hash
row = @stmt.step
return nil if @stmt.done?
@stmt.columns.zip(row).to_h
end
end
class HashResultSet < ResultSet # :nodoc:
alias_method :next, :next_hash
end
end
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