diff --git a/src/sqlite3.erl b/src/sqlite3.erl
index c68d8d5..635edee 100644
--- a/src/sqlite3.erl
+++ b/src/sqlite3.erl
@@ -189,7 +189,7 @@ sql_exec(Db, SQL, Params) ->
     gen_server:call(Db, {sql_bind_and_exec, SQL, Params}).
 
 %%--------------------------------------------------------------------
-%% @spec sql_exec_timeout(Db :: atom(), Sql :: iodata()) -> sql_result()
+%% @spec sql_exec_timeout(Db :: atom(), Sql :: iodata(), Timeout :: timeout()) -> sql_result()
 %% @doc
 %%   Executes the Sql statement directly on the Db database. Returns the
 %%   result of the Sql call.
@@ -200,7 +200,7 @@ sql_exec_timeout(Db, SQL, Timeout) ->
     gen_server:call(Db, {sql_exec, SQL}, Timeout).
 
 %%--------------------------------------------------------------------
-%% @spec sql_exec_timeout(Db :: atom(), Sql :: iodata(), Params) -> sql_result()
+%% @spec sql_exec_timeout(Db :: atom(), Sql :: iodata(), Params, Timeout :: timeout()) -> sql_result()
 %%   Params = [sql_value() | {atom() | string() | integer(), sql_value()}]
 %% @doc
 %%   Executes the Sql statement with parameters Params directly on the Db 
@@ -427,7 +427,7 @@ table_info(Db, Tbl) ->
     gen_server:call(Db, {table_info, Tbl}).
 
 %%--------------------------------------------------------------------
-%% @spec table_info_timeout(Db :: atom(), Tbl :: atom()) -> table_info()
+%% @spec table_info_timeout(Db :: atom(), Tbl :: atom(), Timeout :: timeout()) -> table_info()
 %% @doc
 %%   Returns table schema for Tbl in Db.
 %% @end
@@ -461,7 +461,7 @@ write(Db, Tbl, Data) ->
     gen_server:call(Db, {write, Tbl, Data}).
 
 %%--------------------------------------------------------------------
-%% @spec write_timeout(Db :: atom(), Tbl :: atom(), Data) -> sql_non_query_result()
+%% @spec write_timeout(Db :: atom(), Tbl :: atom(), Data, Timeout :: timeout()) -> sql_non_query_result()
 %%         Data = [{Column :: atom(), Value :: sql_value()}]
 %% @doc
 %%   Write Data into Tbl table in Db database. Value must be of the 
@@ -497,7 +497,7 @@ write_many(Db, Tbl, Data) ->
     gen_server:call(Db, {write_many, Tbl, Data}).
 
 %%--------------------------------------------------------------------
-%% @spec write_many_timeout(Db :: atom(), Tbl :: atom(), Data) -> sql_non_query_result()
+%% @spec write_many_timeout(Db :: atom(), Tbl :: atom(), Data, Timeout :: timeout()) -> sql_non_query_result()
 %%         Data = [[{Column :: atom(), Value :: sql_value()}]]
 %% @doc
 %%   Write all records in Data into table Tbl in database Db. Value 
@@ -530,12 +530,13 @@ update(Tbl, {Key, Value}, Data) ->
 %%    matches the value in Key with Data.
 %% @end
 %%--------------------------------------------------------------------
--spec update(atom(), atom(), {atom(), sql_value()}, [{atom(), sql_value()}]) -> sql_non_query_result().
+-spec update(atom(), atom(), {atom(), sql_value()}, [{atom(), sql_value()}]) -> 
+          sql_non_query_result().
 update(Db, Tbl, {Key, Value}, Data) ->
   gen_server:call(Db, {update, Tbl, Key, Value, Data}).
 
 %%--------------------------------------------------------------------
-%% @spec update_timeout(Db :: atom(), Tbl :: atom(), {Key :: atom(), Value}, Data) -> sql_non_query_result()
+%% @spec update_timeout(Db :: atom(), Tbl :: atom(), {Key :: atom(), Value}, Data, Timeout :: timeout()) -> sql_non_query_result()
 %%        Value = sql_value()
 %%        Data = [{Column :: atom(), Value :: sql_value()}]
 %% @doc
@@ -543,7 +544,8 @@ update(Db, Tbl, {Key, Value}, Data) ->
 %%    matches the value in Key with Data.
 %% @end
 %%--------------------------------------------------------------------
--spec update_timeout(atom(), atom(), {atom(), sql_value()}, [{atom(), sql_value()}], timeout()) -> sql_non_query_result().
+-spec update_timeout(atom(), atom(), {atom(), sql_value()}, [{atom(), sql_value()}], timeout()) -> 
+          sql_non_query_result().
 update_timeout(Db, Tbl, {Key, Value}, Data, Timeout) ->
   gen_server:call(Db, {update, Tbl, Key, Value, Data}, Timeout).
 
@@ -558,7 +560,7 @@ read_all(Db, Tbl) ->
     gen_server:call(Db, {read, Tbl}).
 
 %%--------------------------------------------------------------------
-%% @spec read_all_timeout(Db :: atom(), Table :: atom()) -> sql_result()
+%% @spec read_all_timeout(Db :: atom(), Table :: atom(), Timeout :: timeout()) -> sql_result()
 %% @doc
 %%   Reads all rows from Table in Db.
 %% @end
@@ -578,7 +580,7 @@ read_all(Db, Tbl, Columns) ->
     gen_server:call(Db, {read, Tbl, Columns}).
 
 %%--------------------------------------------------------------------
-%% @spec read_all_timeout(Db :: atom(), Table :: atom(), Columns :: [atom()]) -> sql_result()
+%% @spec read_all_timeout(Db :: atom(), Table :: atom(), Columns :: [atom()], Timeout :: timeout()) -> sql_result()
 %% @doc
 %%   Reads Columns in all rows from Table in Db.
 %% @end
@@ -630,7 +632,7 @@ read(Db, Tbl, {Key, Value}, Columns) ->
     gen_server:call(Db, {read, Tbl, Key, Value, Columns}).
 
 %%--------------------------------------------------------------------
-%% @spec read_timeout(Db :: atom(), Tbl :: atom(), Key) -> sql_result()
+%% @spec read_timeout(Db :: atom(), Tbl :: atom(), Key, Timeout :: timeout()) -> sql_result()
 %%         Key = {Column :: atom(), Value :: sql_value()}
 %% @doc
 %%   Reads a row from Tbl table in Db database such that the Value 
@@ -643,7 +645,7 @@ read_timeout(Db, Tbl, {Column, Value}, Timeout) ->
     gen_server:call(Db, {read, Tbl, Column, Value}, Timeout).
 
 %%--------------------------------------------------------------------
-%% @spec read_timeout(Db, Tbl, Key, Columns) -> [any()]
+%% @spec read_timeout(Db, Tbl, Key, Columns, Timeout :: timeout()) -> [any()]
 %%        Db = atom()
 %%        Tbl = atom()
 %%        Key = {Column :: atom(), Value :: sql_value()}
@@ -672,7 +674,7 @@ delete(Tbl, Key) ->
     delete(?MODULE, Tbl, Key).
 
 %%--------------------------------------------------------------------
-%% @spec delete_timeout(Db :: atom(), Tbl :: atom(), Key) -> sql_non_query_result()
+%% @spec delete_timeout(Db :: atom(), Tbl :: atom(), Key, Timeout :: timeout()) -> sql_non_query_result()
 %%        Key = {Column :: atom(), Value :: sql_value()}
 %% @doc
 %%   Delete a row from Tbl table in Db database such that the Value 
@@ -718,7 +720,7 @@ drop_table(Db, Tbl) ->
     gen_server:call(Db, {drop_table, Tbl}).
 
 %%--------------------------------------------------------------------
-%% @spec drop_table_timeout(Db :: atom(), Tbl :: atom()) -> sql_non_query_result()
+%% @spec drop_table_timeout(Db :: atom(), Tbl :: atom(), Timeout :: timeout()) -> sql_non_query_result()
 %% @doc
 %%   Drop the table Tbl from Db database.
 %% @end
@@ -748,7 +750,7 @@ vacuum(Db) ->
     gen_server:call(Db, vacuum).
 
 %%--------------------------------------------------------------------
-%% @spec vacuum_timeout(Db :: atom()) -> sql_non_query_result()
+%% @spec vacuum_timeout(Db :: atom(), Timeout :: timeout()) -> sql_non_query_result()
 %% @doc
 %%   Vacuum the Db database.
 %% @end
@@ -1183,15 +1185,40 @@ build_primary_key_constraint(Tail, Acc) ->
 %%     {no_on_conflict, NoOnConflictClause}.
 
 %%--------------------------------------------------------------------
-%% @type sql_value() = number() | 'null' | iodata().
+%% @type sql_value() = null | number() | iodata() | {blob, binary()}.
 %% 
-%% Values accepted in SQL statements include numbers, atom 'null',
-%% and io:iolist().
+%% Values accepted in SQL statements are atom 'null', numbers, 
+%% strings (represented as iodata()) and blobs.
+%% @end
+%% @type sql_type() = integer | text | double | blob | atom() | string().
+%% 
+%% Types of SQLite columns are represented by atoms 'integer', 'text', 'double',
+%% 'blob'. Other atoms and strings may also be used (e.g. "VARCHAR(20)", 'smallint', etc.)
+%% See [http://www.sqlite.org/datatype3.html].
+%% @end
+%% @type pk_constraint() = autoincrement | desc | asc.
+%% See {@link pk_constraints()}.
+%% @type pk_constraints() = pk_constraint() | [pk_constraint()].
+%% See {@link column_constraint()}.
+%% @type column_constraint() = non_null | primary_key | {primary_key, pk_constraints()}
+%%                             | unique | {default, sql_value()}.
+%% See {@link column_constraints()}.
+%% @type column_constraints() = column_constraint() | [column_constraint()].
+%% See {@link table_info()}.
+%% @type table_info() = [{atom(), sql_type()} | {atom(), sql_type(), column_constraints()}].
+%% 
+%% Describes the columns of an SQLite table: each tuple contains name, type and constraints (if any)
+%% of one column.
+%% @end
+%% @type table_constraint() = {primary_key, [atom()]} | {unique, [atom()]}.
+%% @type table_constraints() = table_constraint() | [table_constraint()].
+%% 
+%% Currently supported constraints for {@link table_info()} and {@link sqlite3:create_table/4}.
 %% @end
 %% @type sqlite_error() = {'error', integer(), string()}.
 %% 
 %% Errors are reported by their SQLite result code 
-%% (http://www.sqlite.org/c3ref/c_busy_recovery.html) and a string containing 
+%% ([http://www.sqlite.org/c3ref/c_busy_recovery.html]) and a string containing 
 %% English-language text that describes the error.
 %% @end
 %% @type sql_non_query_result() = ok | sqlite_error() | {rowid, integer()}.
diff --git a/src/sqlite3_lib.erl b/src/sqlite3_lib.erl
index ded64d7..f3e2979 100644
--- a/src/sqlite3_lib.erl
+++ b/src/sqlite3_lib.erl
@@ -54,7 +54,10 @@ col_type_to_atom("TEXT") ->
 col_type_to_atom("REAL") ->
     double;
 col_type_to_atom("BLOB") ->
-    blob.
+    blob;
+col_type_to_atom(String) ->
+    list_to_atom(string:to_lower(String)).
+
 
 %%--------------------------------------------------------------------
 %% @spec value_to_sql_unsafe(Value :: sql_value()) -> iolist()