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#!/usr/bin/ruby
# Copyright (c) 2006, 2007 Peter Palfrader
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
require "dbi"
class WeaselDbQueryHandle
def initialize(sth)
@sth = sth
end
def next()
row = @sth.fetch_hash
if row
return row
else
@sth.finish
return nil
end
end
end
class Db
def initialize(host, database, user, password)
@dbh = DBI.connect("dbi:Pg:#{database}:#{host}", user, password);
@dbh['AutoCommit'] = false
@transaction = false
@pre_initial_transaction=true
end
def do(query,*args)
@dbh.do(query,*args)
end
def transaction_begin()
@dbh.do("BEGIN") unless @pre_initial_transaction
@transaction = true
@pre_initial_transaction=false
end
def transaction_commit()
@dbh.do("COMMIT")
@transaction = false
end
def transaction_rollback()
@dbh.do("ROLLBACK")
end
def get_primarykey_name(table);
#return 'ref';
return table+'_id';
end
def update(table, values, keys)
cols = []
vals = []
values.each_pair{ |k,v|
cols << "#{k}=?"
vals << v
}
wheres = []
keys.each_pair{ |k,v|
wheres << "#{k}=?"
vals << v
}
throw "update value set empty" unless cols.size > 0
throw "where clause empty" unless wheres.size > 0
query = "UPDATE #{table} SET #{cols.join(',')} WHERE #{wheres.join(' AND ')}"
transaction_begin unless transaction_before=@transaction
r = @dbh.do(query, *vals)
transaction_commit unless transaction_before
return r
end
def update_row(table, values)
pk_name = get_primarykey_name(table);
throw "Ref not defined" unless values[pk_name]
return update(table, values.clone.delete_if{|k,v| k == pk_name}, { pk_name => values[pk_name] });
end
def insert(table, values)
cols = values.keys
vals = values.values
qmarks = values.values.collect{ '?' }
query = "INSERT INTO #{table} (#{cols.join(',')}) VALUES (#{qmarks.join(',')})"
transaction_begin unless transaction_before=@transaction
@dbh.do(query, *vals)
transaction_commit unless transaction_before
end
def insert_row(table, values)
pk_name = get_primarykey_name(table);
if values[pk_name]
insert(table, values)
else
transaction_begin unless transaction_before=@transaction
row = query_row("SELECT nextval(pg_get_serial_sequence('#{table}', '#{pk_name}')) AS newref");
throw "No newref?" unless row['newref']
values[pk_name] = row['newref']
insert(table, values);
transaction_commit unless transaction_before
end
end
def delete_row(table, ref)
pk_name = get_primarykey_name(table);
query = "DELETE FROM #{table} WHERE #{pk_name}=?"
transaction_begin unless transaction_before=@transaction
@dbh.do(query, ref)
transaction_commit unless transaction_before
end
def query(query, *params)
sth = @dbh.execute(query, *params)
while row = sth.fetch_hash
yield row
end
sth.finish
end
# nil if no results
# hash if one match
# throw otherwise
def query_row(query, *params)
sth = @dbh.execute(query, *params)
row = sth.fetch_hash
if row == nil
sth.finish
return nil
elsif sth.fetch_hash != nil
sth.finish
throw "More than one result when querying for #{query}"
else
sth.finish
return row
end
end
def query_all(query, *params)
sth = @dbh.execute(query, *params)
rows = sth.fetch_all
return nil if rows.size == 0
return rows
end
def query2(query, *params)
sth = @dbh.execute(query, *params)
return WeaselDbQueryHandle.new(sth)
end
end
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