Copied PostgreSQL erlang library from ejabberd-modules SVN

1 files changed, 96 insertions, 0 deletions

diff --git a/src/pgsql/pgsql.erl b/src/pgsql/pgsql.erl
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+%%% File    : pgsql.erl
+%%% Author  : Christian Sunesson <chsu79@gmail.com>
+%%% Description : PostgresQL interface
+%%% Created : 11 May 2005
+
+%%
+%% API for accessing the postgres driver.
+%%
+
+-module(pgsql).
+-export([connect/1, connect/4, connect/5]).
+
+-export([squery/2, 
+	 pquery/3, 
+	 terminate/1, 
+	 prepare/3, unprepare/2, 
+	 execute/3]).
+
+
+connect(Host, Database, User, Password) ->
+    connect([{database, Database},
+	     {host, Host},
+	     {user, User},
+	     {password, Password}]).
+
+connect(Host, Database, User, Password, Port) ->
+    connect([{database, Database},
+	     {host, Host},
+	     {user, User},
+	     {port, Port},
+	     {password, Password}]).
+
+connect(Options) ->
+    pgsql_proto:start(Options).
+
+%% Close a connection
+terminate(Db) ->
+    gen_server:call(Db, terminate).
+
+%%% In the "simple query" protocol, the frontend just sends a 
+%%% textual query string, which is parsed and immediately 
+%%% executed by the backend.  
+
+%% A simple query can contain multiple statements (separated with a semi-colon),
+%% and each statement's response.
+
+%%% squery(Db, Query) -> {ok, Results} | ... no real error handling
+%%% Query = string()
+%%% Results = [Result]
+%%% Result = {"SELECT", RowDesc, ResultSet} | ...
+squery(Db, Query) ->
+    gen_server:call(Db, {squery, Query}, infinity).
+
+%%% In the "extended query" protocol, processing of queries is 
+%%% separated into multiple steps: parsing, binding of parameter
+%%% values, and execution. This offers flexibility and performance
+%%% benefits, at the cost of extra complexity.
+
+%%% pquery(Db, Query, Params) -> {ok, Command, Status, NameTypes, Rows} | timeout | ...
+%%% Query = string()
+%%% Params = [term()]
+%%% Command = string()
+%%% Status = idle | transaction | failed_transaction
+%%% NameTypes = [{ColName, ColType}]
+%%% Rows = [list()]
+pquery(Db, Query, Params) ->
+    gen_server:call(Db, {equery, {Query, Params}}).
+
+%%% prepare(Db, Name, Query) -> {ok, Status, ParamTypes, ResultTypes}
+%%% Status = idle | transaction | failed_transaction
+%%% ParamTypes = [atom()]
+%%% ResultTypes = [{ColName, ColType}]
+prepare(Db, Name, Query) when is_atom(Name) ->
+    gen_server:call(Db, {prepare, {atom_to_list(Name), Query}}).
+
+%%% unprepare(Db, Name) -> ok | timeout | ...
+%%% Name = atom()
+unprepare(Db, Name) when is_atom(Name) ->
+    gen_server:call(Db, {unprepare, atom_to_list(Name)}).
+
+%%% execute(Db, Name, Params) -> {ok, Result} | timeout | ...
+%%% Result = {'INSERT', NRows} |
+%%%          {'DELETE', NRows} |
+%%%          {'SELECT', ResultSet} |
+%%%          ...
+%%% ResultSet = [Row]
+%%% Row = list()
+execute(Db, Name, Params) when is_atom(Name), is_list(Params) ->
+    Ref = make_ref(),
+    Db ! {execute, Ref, self(), {atom_to_list(Name), Params}},
+    receive
+	{pgsql, Ref, Result} ->
+	    {ok, Result}
+    after 5000 ->
+	    timeout
+    end.