Merge pull request #25 from maxlapshin/patch-1

sqlite3:add_columns feature

src/sqlite3.erl

@@ -29,6 +29,7 @@
          columns_timeout/3]).
 -export([create_table/2, create_table/3, create_table/4, create_table_timeout/4,
          create_table_timeout/5]).
+-export([add_columns/2, add_columns/3]).
 -export([list_tables/0, list_tables/1, list_tables_timeout/2,
          table_info/1, table_info/2, table_info_timeout/3]).
 -export([write/2, write/3, write_timeout/4, write_many/2, write_many/3,
@@ -367,6 +368,34 @@ create_table(Db, Tbl, Columns, Constraints) ->
 create_table_timeout(Db, Tbl, Columns, Constraints, Timeout) ->
     gen_server:call(Db, {create_table, Tbl, Columns, Constraints}, Timeout).
 
+
+%%--------------------------------------------------------------------
+%% @doc
+%%   Add columns to table structure
+%%   table structure is a list of {column name, column type} pairs.
+%%   e.g. [{name, text}, {age, integer}]
+%%
+%%   Returns the result of the create table call.
+%% @end
+%%--------------------------------------------------------------------
+-spec add_columns(table_id(), table_info()) -> sql_non_query_result().
+add_columns(Tbl, Columns) ->
+    add_columns(?MODULE, Tbl, Columns).
+
+%%--------------------------------------------------------------------
+%% @doc
+%%   Add columns to table structure
+%%   The table structure is a list of {column name, column type} pairs.
+%%   e.g. [{name, text}, {age, integer}]
+%%
+%%   Returns the result of the create table call.
+%% @end
+%%--------------------------------------------------------------------
+-spec add_columns(db(), table_id(), table_info()) -> sql_non_query_result().
+add_columns(Db, Tbl, Columns) ->
+    gen_server:call(Db, {add_columns, Tbl, Columns}).
+
+
 %%--------------------------------------------------------------------
 %% @doc
 %%   Returns a list of tables.

src/sqlite3_lib.erl

@@ -16,6 +16,7 @@
 -export([value_to_sql/1, value_to_sql_unsafe/1, sql_to_value/1, escape/1, bin_to_hex/1]).
 -export([write_value_sql/1, write_col_sql/1]).
 -export([create_table_sql/2, create_table_sql/3, drop_table_sql/1]). 
+-export([add_columns_sql/2]).
 -export([write_sql/2, update_sql/4, update_set_sql/1, delete_sql/3]).
 -export([read_sql/1, read_sql/2, read_sql/3, read_sql/4, read_cols_sql/1]).
 
@@ -203,6 +204,16 @@ create_table_sql(Tbl, Columns, TblConstraints) ->
      table_constraint_sql(TblConstraints), 
      ", CHECK ('", Type, "'='", Type, "'));"].
 
+%%--------------------------------------------------------------------
+%% @doc Generates a alter table stmt in SQL.
+%% @end
+%%--------------------------------------------------------------------
+-spec add_columns_sql(table_id(),table_info()) -> iolist().
+add_columns_sql(Tbl, Columns) ->
+    {_, TName} = encode_table_id(Tbl),
+    ["ALTER TABLE ", TName, " ADD COLUMN ",
+     map_intersperse(fun column_sql_for_create_table/1, Columns, ", "),";"].
+
 %%--------------------------------------------------------------------
 %% @doc 
 %%    Using Key as the column name and Data as list of column names