[PHP] Two ideas for updating intermediate joined table data: php ideas

[PHP] Two ideas for updating intermediate joined table data: php ideas

/* Configure /*---------------------------------------------------------------------------------------------------------

@ Blackeye poet <www. chenwei. ws>

Optional ---------------------------------------------------------------------------------------------------------*/

Intermediate join table: the intermediate table only stores the primary key of table 1 and the primary key of table 2, that is, multiple to multiple forms.

(Adding and deleting data is not part of the idea)

 

/*
| -----------------------------------------------------------
| Method 1: Delete all old data and then add new data
| @ Chenwei <www. chenwei. ws> | -----------------------------------------------------------
*/$ Res = $ this-> classes-> classEdit ($ id, $ data); // modify the primary table data if ($ res) {// Delete joined table data first $ bool = $ this-> lesson_classes-> lessonClassesDel ($ id); if ($ bool ){
// Cyclically assemble conditions to add data foreach ($ lesson_ids as $ val)
{$ Arr = array ('class _ id' => $ id, 'lesson _ id' => $ val); // data
$ Res = $ this-> lesson_classes-> lessonClassesAdd ($ arr); // execute add} $ this-> show_tips ('Operation successful! ');} Else {$ this-> show_tips (' operation failed! ');}

// Disadvantage: it is unsafe to delete data in large batches, which poses a certain level of security risks.

 

 

/*
| ---------------------------------------------------------
| Method 2: add only what is needed and delete only what is to be deleted
| @ Chenwei <www. chenwei. ws> | ---------------------------------------------------------
* /// The old data found in the database: $ arr_old (processed one-dimensional array) // The new data submitted: $ arr_new (the obtained one-dimensional array) $ intersect = array_intersect ($ arr_old, $ arr_new); // intersection (the part to be retained, not to be processed) $ result_del = array_diff ($ arr_old, $ intersect ); // $ result_add = array_diff ($ arr_new, $ intersect) to be deleted from the old data ); // Add new data to the new data if ($ result_add & is_array ($ result_add) {foreach ($ result_add as $ val) {$ data_add = array ('class _ id' => $ id, 'lesson _ id' => $ val ); // data $ bool_add = $ this-> lesson_classes-> lessonClassesAdd ($ data_add ); // execute add} // Delete the data to be cleared if ($ result_del & is_array ($ result_del) {foreach ($ result_del as $ val) {$ bool_del = $ this-> lesson_classes-> lessonClassesDel ($ id, $ val); // execute Delete }}

If ($ bool_add & $ bool_del)
{
$ This-> show_tips ('Operation successful! ');
}
Else
{
$ This-> show_tips ('Operation failed! ');
}


// Features: Targeted addition and deletion of data, higher security than the first method

 

If there are any errors or better solutions, please leave a message.

Association between two tables A and B in the MYSQL + PHP Database

Select 'A'. *, 'B'. 'mentor name' WHERE 'A'. 'mentor id' = 'B'. 'mentor id'
The instructor ID in Table A is an index.
The tutor ID in Table B is the primary key.

This is not clear .. Helpless
You write the field name in your database, instead of text.
What else do I need to retrieve?
Write the SQL directly.

If ($ condition = ""){
$ Condition = "WHERE sid LIKE \" % ". $ id." % \"";
} Else {
$ Condition. = "AND sid LIKE \" % ". $ id." % \"";
}
Change
Condition = "AND sid LIKE \" % ". $ id." % \"";

Then SQL
$ SQL = 'select 'data '. *, 'teacher '. 'tname' FROM 'data', 'teacher' WHERE 'data '. 'tid' = 'teacher '. 'tid ''. $ condition
That's it.

In php, I used a CI framework to develop a program. I have two tables connected. Can I delete the data associated with two tables at the same time? How do I write the deleted code?

Delete from A where. ID in (select B. ID from B where B. sum> 100) This is just an example of table connection deletion and table connection query select * from a left join B on. id = B. id where. id = 1 update a, B set. id = 12 wehre B. id = 2 not tested