Question

Let there be a PHP method which is supposed to insert a few rows into a MySQL database, each time it’s called. Unfortunately these records represent a hierarchy and I want to persist this hierarchy by adding a key for each level. An example could be looking like this:

id    hier_key_1    hier_key_2    value
0     0             0             val1
1     0             0             val2
2     1             0             val3
3     1             0             val4
4     2             1             val5
5     2             1             val6

My current solution works like this:

1. Insert new record in hier_key_1 table
2. Select auto-incremented id of this record
3. Insert new record in hier_key_2 table
4. Select auto-incremented id of this record
5. Insert record in table with all values and hier_key_1 and hier_key_2 as foreign keys pointing to their tables

Is there a way to simplify this, i.e. does the insert method provides any kind of return value including the keys of the inserted data? Or should I try to generate unique keys in my PHP method and check for duplicates afterwards?

Answer 1

Yes, there are:

PHP:

$query = "INSERT INTO hier_key_1(hier_key_1) VALUES (0)"); 
if( !mysql_query($query) ) 
{/*insert failed*/} 

$id_key_1 = mysql_insert_id();

//... and so on... 

MYSQL – SQL

INSERT INTO hier_key_1(hier_key_1) VALUES (0); SET @id_key_1 =
LAST_INSERT_ID();

INSERT INTO hier_key_2(hier_key_2) VALUES (0); SET @id_key_2 =
LAST_INSERT_ID();

INSERT INTO table_name(id, hier_key_1, hier_key_1,value) VALUES (0,
@id_key_1,@id_key_2,value1);

and so on..

greetings