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Construct SQL queries as iolists, not as strings

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This commit is contained in:
Alexey Romanov
2010-10-05 14:27:28 +04:00
parent 709f3e8c5a
commit 842df283d0
2 changed files with 41 additions and 43 deletions
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74
src/sqlite3_lib.erl
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@@ -56,7 +56,7 @@ write_value_sql(Values) ->
(?NULL_ATOM) -> "null";
(X) -> io_lib:format("'~s'", [X])
end, Values),
string:join(StrValues, ",").
intersperse(StrValues, ",").
%%--------------------------------------------------------------------
%% @spec write_col_sql([atom()]) -> string()
@@ -68,7 +68,7 @@ write_col_sql(Cols) ->
StrCols = lists:map(fun(X) ->
atom_to_list(X)
end, Cols),
string:join(StrCols, ",").
intersperse(StrCols, ",").
%%--------------------------------------------------------------------
%% @spec replace (String) -> string ()
@@ -102,18 +102,15 @@ replace ([H | T], L) ->
update_set_sql (Data) ->
Set = lists:map (fun
({Col, Value}) when is_integer (Value) ->
string:join (
[atom_to_list (Col), integer_to_list (Value)], " = ");
[atom_to_list (Col), " = ", integer_to_list (Value)];
({Col, Value}) when is_float (Value) ->
string:join (
[atom_to_list (Col), integer_to_list (Value)], " = ");
[atom_to_list (Col), " = ", float_to_list (Value)];
({Col, Value}) ->
string:join (
[atom_to_list (Col),
io_lib:format ("\"~s\"", [replace (Value)])], " = ")
[atom_to_list (Col), " = ",
io_lib:format ("\"~s\"", [replace (Value)])]
end,
Data),
string:join (Set, ", ").
intersperse(Set, ", ").
%%--------------------------------------------------------------------
%% @spec read_cols_sql (Columns::[atom ()]) -> string ()
@@ -123,8 +120,8 @@ update_set_sql (Data) ->
%%--------------------------------------------------------------------
-spec (read_cols_sql/1::([atom ()]) -> string ()).
read_cols_sql (Columns) ->
string:join (
lists:map (fun (A) -> atom_to_list (A) end, Columns), ", ").
intersperse(
lists:map(fun atom_to_list/1, Columns), ", ").
%%--------------------------------------------------------------------
%% @spec create_table_sql(Tbl, [{ColName, Type}]) -> string()
@@ -138,11 +135,11 @@ read_cols_sql (Columns) ->
create_table_sql(Tbl, [{ColName, Type} | Tl]) ->
CT = io_lib:format("CREATE TABLE ~p ", [Tbl]),
Start = io_lib:format("(~p ~s PRIMARY KEY, ", [ColName, sqlite3_lib:col_type(Type)]),
End = string:join(
lists:map(fun({Name0, Type0}) ->
io_lib:format("~p ~s", [Name0, sqlite3_lib:col_type(Type0)])
end, Tl), ", ") ++ ");",
lists:flatten(CT ++ Start ++ End).
End = [intersperse(
lists:map(fun({Name0, Type0}) ->
io_lib:format("~p ~s", [Name0, sqlite3_lib:col_type(Type0)])
end, Tl), ", "), ");"],
[CT, Start, End].
%%--------------------------------------------------------------------
%% @spec update_sql (Tbl, Key, Value, Data) -> string ()
@@ -159,13 +156,12 @@ create_table_sql(Tbl, [{ColName, Type} | Tl]) ->
-type(sql_value() :: string() | integer() | float()).
-spec (update_sql/4::(atom (), atom (), atom (), [{atom (), sql_value ()}]) -> string ()).
update_sql (Tbl, Key, Value, Data) ->
lists:flatten (
io_lib:format ("UPDATE ~p SET ~s WHERE ~p = ~p;",
[Tbl,
sqlite3_lib:update_set_sql (Data),
Key,
Value
])).
io_lib:format("UPDATE ~p SET ~s WHERE ~p = ~p;",
[Tbl,
sqlite3_lib:update_set_sql (Data),
Key,
Value
]).
%%--------------------------------------------------------------------
%% @spec write_sql(Tbl, Data) -> string()
@@ -178,11 +174,11 @@ update_sql (Tbl, Key, Value, Data) ->
-spec(write_sql/2::(atom(), [{atom(), sql_value()}]) -> string()).
write_sql(Tbl, Data) ->
{Cols, Values} = lists:unzip(Data),
lists:flatten(
io_lib:format("INSERT INTO ~p (~s) values (~s);",
[Tbl,
sqlite3_lib:write_col_sql(Cols),
sqlite3_lib:write_value_sql(Values)])).
io_lib:format("INSERT INTO ~p (~s) values (~s);",
[Tbl,
sqlite3_lib:write_col_sql(Cols),
sqlite3_lib:write_value_sql(Values)
]).
%%--------------------------------------------------------------------
%% @spec read_sql(Tbl, Key, Value) -> string()
@@ -195,8 +191,7 @@ write_sql(Tbl, Data) ->
%%--------------------------------------------------------------------
-spec(read_sql/3::(atom(), atom(), sql_value()) -> string()).
read_sql(Tbl, Key, Value) ->
lists:flatten(
io_lib:format("SELECT * FROM ~p WHERE ~p = ~p;", [Tbl, Key, Value])).
io_lib:format("SELECT * FROM ~p WHERE ~p = ~p;", [Tbl, Key, Value]).
%%--------------------------------------------------------------------
%% @spec read_sql (Tbl, Key, Value, Columns) -> string ()
@@ -211,13 +206,12 @@ read_sql(Tbl, Key, Value) ->
%%--------------------------------------------------------------------
-spec (read_sql/4::(atom (), atom (), sql_value (), [atom ()]) -> string ()).
read_sql (Tbl, Key, Value, Columns) ->
lists:flatten (
io_lib:format ("SELECT ~s FROM ~p WHERE ~p = ~p;",
io_lib:format("SELECT ~s FROM ~p WHERE ~p = ~p;",
[sqlite3_lib:read_cols_sql (Columns),
Tbl,
Key,
Value
])).
]).
%%--------------------------------------------------------------------
%% @spec delete_sql(Tbl, Key, Value) -> string()
@@ -230,8 +224,7 @@ read_sql (Tbl, Key, Value, Columns) ->
%%--------------------------------------------------------------------
-spec(delete_sql/3::(atom(), atom(), sql_value()) -> string()).
delete_sql(Tbl, Key, Value) ->
lists:flatten(
io_lib:format("DELETE FROM ~p WHERE ~p = ~p;", [Tbl, Key, Value])).
io_lib:format("DELETE FROM ~p WHERE ~p = ~p;", [Tbl, Key, Value]).
%%--------------------------------------------------------------------
%% @spec drop_table(Tbl) -> string()
@@ -241,9 +234,14 @@ delete_sql(Tbl, Key, Value) ->
%%--------------------------------------------------------------------
-spec(drop_table/1::(atom()) -> string()).
drop_table(Tbl) ->
lists:flatten(
io_lib:format("DROP TABLE ~p;", [Tbl])).
io_lib:format("DROP TABLE ~p;", [Tbl]).
%%====================================================================
%% Internal functions
%%====================================================================
%% @doc Works like string:join for iolists
intersperse([], _Sep) -> [];
intersperse([Elem], _Sep) -> [Elem];
intersperse([Head | Tail], Sep) -> [Head, Sep | intersperse(Tail, Sep)].