php - Saving custom fields data as right serialized array format in wp_postmeta -

i working on wordpress woocommerce , using wck plugin custom fields. creating products programatically.

i need save custom fields data array in database progrmatically. not saving correctly , not showing custom field values in backend products. using code.

 $data= array(     'alternative-product-names' => $alternative_pname,     'manufacturers-part-number' => $manufature_park_number,     'currently-packaged'=> $currently_packaged,     'other-package-options' => $other_pkg_opt,     'inner-pack-qty' => $inner_pack_qty,     'inner-pack-dimensions' => $inner_pck_dimension,     'packaging-picture'=>''     );  update_post_meta( $post_id, 'productextrainfo1234', $data ); 

i need save data in format:

a:1:{i:0;a:15:{s:25:"alternative-product-names";s:4:"fgfg";s:25:"manufacturers-part-number";s:4:"gffg";s:18:"currently-packaged";s:4:"fgfg";s:21:"other-package-options";s:4:"fgfg";s:14:"inner-pack-qty";s:4:"fggf";s:21:"inner-pack-dimensions";s:17:"packaging-picture";s:3:"561";}}

after testing code:

first, have 7 lines of key/values in array, serialized string can't begin a:1:{i:0;a:15:{ … instead a:1:{i:0;a:7:{ ….

second, need embed array in empty array correct format want:
a:1:{i:0;a:7:{ … }};.

so code have this:

$data= array(      array(         'alternative-product-names' => $alternative_pname,         'manufacturers-part-number' => $manufature_park_number,         'currently-packaged'        => $currently_packaged,         'other-package-options'     => $other_pkg_opt,         'inner-pack-qty'            => $inner_pack_qty,         'inner-pack-dimensions'     => $inner_pck_dimension,         'packaging-picture'         => ''     ) );  update_post_meta( $product_id, 'productextrainfo1234', $data ); 

this way serialized data value in database:

a:1:{i:0;a:7:{s:25:"alternative-product-names";n;s:25:"manufacturers-part-number";n;s:18:"currently-packaged";n;s:21:"other-package-options";n;s:14:"inner-pack-qty";n;s:21:"inner-pack-dimensions";n;s:17:"packaging-picture";s:0:"";}}

instead of:

a:7:{s:25:"alternative-product-names";n;s:25:"manufacturers-part-number";n;s:18:"currently-packaged";n;s:21:"other-package-options";n;s:14:"inner-pack-qty";n;s:21:"inner-pack-dimensions";n;s:17:"packaging-picture";s:0:"";}