Class: JDBC::Result

Inherits:
Object
  • Object
show all
Defined in:
lib/jdbc/result.rb

Overview

Result wraps a java ResultSet, and provides methods to both fetch rows one at a time, as well as ruby iterators. All rows are automatically converted to a ruby Array or Hash when they are fetched. Each column is casted to the equivalent ruby object if possible, otherwise it will be a String.

Instance Method Summary collapse

Constructor Details

#initialize(resultSet, statement) ⇒ Result

Takes a java ResultSet and Statement. You should not have to call this. A Result will usually be instantiated by a DB or PreparedStatement.



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# File 'lib/jdbc/result.rb', line 10

def initialize(resultSet, statement)
  @rs = resultSet
  @stmt = statement
  @columns = get_rs_meta_data
end

Instance Method Details

#close ⇒ Object

Closes the Result



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# File 'lib/jdbc/result.rb', line 74

def close
  @rs.close unless @rs.nil?
  @stmt.close unless @stmt.nil?
end

#each ⇒ Object

Returns each row as an Array to the provided block. Will automatically close the Result after the block exits.



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# File 'lib/jdbc/result.rb', line 59

def each
  while(result = fetch)
    yield(result)
  end
end

#each_hash ⇒ Object

Returns each row as an Hash to the provided block. The column names are the keys. Will automatically close the Result after the block exits.



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# File 'lib/jdbc/result.rb', line 67

def each_hash
  while(result = fetch_hash)
    yield(result)
  end
end

#fetch ⇒ Object

Fetches the next row and returns it as an Array. Returns nil if no more rows are available and closes the Result.



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# File 'lib/jdbc/result.rb', line 18

def fetch
  if @rs.next
    result = []
  
    @columns.each do |column| 
      result << fetch_and_cast(@rs, column)
    end
    
    return result
  end
  
  close
  
  return nil
end

#fetch_hash ⇒ Object

Fetches the next row and returns it as a Hash. The column names are the keys. Returns nil is no more rows are available and closes the Result.

Note: All column names are automatically lowercased for consistency since databases differ in behavior on this aspect. (ex: Derby is uppercase, Postgres is lowercase, and Mysql depends on how the table was created.)



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# File 'lib/jdbc/result.rb', line 41

def fetch_hash
  if @rs.next
    result = {}
  
    @columns.each do |column| 
      result[column[:name]] = fetch_and_cast(@rs, column)
    end
    
    return result
  end
  
  close
  
  return nil
end