%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1999-2018. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(company_o).
-export([sinit/0, init/0,insert_emp/3,females/0,
female_bosses/0, raise_females/1, over_write/2, raise/2,
bad_raise/2, get_emps/2, get_emps2/2]).
-import(mnesia, [transaction/1]).
%0
-include_lib("stdlib/include/qlc.hrl").
-include("company_o.hrl").
sinit() ->
mnesia:create_schema([node()]).
init() ->
mnesia:create_table(employee,
[{attributes, record_info(fields, employee)}]),
mnesia:create_table(dept,
[{attributes, record_info(fields, dept)}]),
mnesia:create_table(project,
[{attributes, record_info(fields, project)}]).
%0
%1
insert_emp(Emp, DeptId, ProjNames) ->
Fun = fun() ->
mnesia:write(Emp#employee{dept = DeptId,
projects = ProjNames})
end,
mnesia:transaction(Fun).
%1
%2
females() ->
F = fun() ->
Q = qlc:q([E#employee.name || E <- mnesia:table(employee),
E#employee.sex == female]),
qlc:e(Q)
end,
mnesia:transaction(F).
%2
%3
female_bosses() ->
F = fun() -> qlc:e(qlc:q(
[{E#employee.name, Boss#employee.name} ||
E <- mnesia:table(employee),
Boss <- mnesia:table(employee),
Boss#employee.emp_no == E#employee.manager,
E#employee.sex == female]
))
end,
mnesia:transaction(F).
%4
raise_females(Amount) ->
F = fun() ->
Q = qlc:q([E || E <- mnesia:table(employee),
E#employee.sex == female]),
Fs = qlc:e(Q),
over_write(Fs, Amount)
end,
mnesia:transaction(F).
over_write([E|Tail], Amount) ->
Salary = E#employee.salary + Amount,
New = E#employee{salary = Salary},
mnesia:write(New),
1 + over_write(Tail, Amount);
over_write([], _) ->
0.
%4
%5
raise(Eno, Raise) ->
F = fun() ->
[E] = mnesia:read({employee, Eno}),
Salary = E#employee.salary + Raise,
New = E#employee{salary = Salary},
mnesia:write(New)
end,
mnesia:transaction(F).
%5
%6
bad_raise(Eno, Raise) ->
F = fun() ->
[E] = mnesia:read({employee, Eno}),
Salary = E#employee.salary + Raise,
New = E#employee{salary = Salary},
io:format("Trying to write ... ~n", []),
mnesia:write(New)
end,
mnesia:transaction(F).
%6
%9
get_emps(Salary, Dep) ->
Q = qlc:q(
[E || E <- mnesia:table(employee),
E#employee.salary > Salary,
E#employee.dept == Dep]
),
F = fun() -> qlc:e(Q) end,
transaction(F).
%9
%10
get_emps2(Salary, Dep) ->
Epat0 = mnesia:table_info(employee, wild_pattern),
Epat = Epat0#employee{dept = Dep},
F = fun() ->
All = mnesia:match_object(Epat),
[E || E <-All, E#employee.salary > Salary ]
end,
mnesia:transaction(F).
%10
