wpdb insert problem

I use wpdb insert query to insert a role into the database. Here is the code:
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$wpdb->insert({$wpdb->base_prefix}bp_my_markers, array( ‘id’=> ’31’, ‘name’ => ‘myname’,’address’ => ‘2500 main street’, ‘lat’ => ‘47.612823’, ‘lng’ => ‘-122.345673’, ‘type’ => ‘bar’));
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but it doesn’t work.

Then I tried the following code to do the same thing.
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$wpdb->query( $wpdb->prepare( “INSERT INTO {$wpdb->base_prefix}bp_my_markers (id, name, address, lat, lng, type)VALUES (’31’, ‘myname’, ‘2500 main street’, ‘47.612823’,’ 122.345673′,’bar’)”));
////////////////////////////////////////////////////

This time it works.

I really don’t know what’s wrong with my $wpdb->insert code. Could someone tell me?

I know the latter way can be used to protect queries against SQL jnjection attacks, but are there any other differences between the two? Which one is better?

Thanks.