DB batch methods: code review (v4.0.4)

BaseBuilder::setInsertBatch($key, string $value = '', bool $escape = null) : ?BaseBuilder

For the method to work correctly, the first argument must be (sample data)

PHP Code:

// array of key/value pairs arrays
$data = [
    [
        'field1' => 'value1',
        'field2' => 1,
    ],
    [
        'field1' => 'value2',
        'field2' => 2,
    ]
];
// array of objects
class Data 
{
    public $field1 = 'value1';
    public $field2 = 'value2';
}

$data = [
    new Data(),
    new Data(),    
];
// an object containing arrays of values
class Data 
{
    public $field1 = ['value1', 'value2'];
    public $field2 = [1, 2];
}

$data = new Data; 


At first, array check

PHP Code:

if (! is_array($key))
{
    $key = [$key => $value];
} 


Someone copy the code from the BaseBuilder::set() method. :-/

Since the $value variable has the typehint 'string', all data will be converted to a string if possible or throw an exception.
Ok. The $key = 'field' (is not array) and $value = 'string'; 
As a result, we get: $key = ['field' => 'string']; 
Does this array match the sample data? No!

This means the second parameter of the method ($value) is meaningless

If the array check fails, the method should be stopped. Return $this or throw exception.

Missing subarray check 1

PHP Code:

$keys = array_keys($this->objectToArray(current($key))); 


$key = ['field' => 'string']; and we have "Warning: array_keys() expects parameter 1 to be array" 

Missing subarray check 2
Ok. The fist element the $key is array. Second?

PHP Code:

$key = [
    ['field' => 'value'],
    'value',
    'field'
];

foreach ($key as $row)
{
    $row = $this->objectToArray($row);
    if (array_diff($keys, array_keys($row)) !== [] || array_diff(array_keys($row), $keys) !== [])
    { 


And again "Warning: array_keys() expects parameter 1 to be array"

We can compare two arrays like $a === $b 

PHP Code:

sort($keys);
//...
//...
$keys === array_keys(ksort($row));
// no more array_diff(); 


$row = $clean; For what?

PHP Code:

$clean = [];
foreach ($row as $k => $value)
{
    $clean[] = ':' . $this->setBind($k, $value, $escape) . ':';
}

$row = $clean;

$this->QBSet[] = '(' . implode(',', $row) . ')'; 


BaseBuilder::setUpdateBatch($key, string $index = '', bool $escape = null) : ?BaseBuilder

Missing subarray check. 
Hello. I am the second parameter of the method. My name is $index. Why am I here? Who am I? 
I guess I was copied from the BaseBuilder::set() method?
Meaningless method parameter

Both methods 

Method return type 
* @return $this|null
Method chaining? Forget. We can return null to you! 

Variable names. 
Bad: $key, $v, $v2, $k2, $row
Good: $data, $fields, $pairs, $field, $value

BaseBuilder::updateBatch(array $set = null, string $index = null, int $batchSize = 100)

Can $index be null? No, this is a required parameter
Can $set be null? Yes. We can use the BaseBuilder::setUpdateBatch() method
Can $set be an object? Yes. The data is prepared in the BaseBuilder::setUpdateBatch() method.

Maybe like this?
* @param array|object|null $set 
BaseBuilder::updateBatch(string $index, $set = null, int $batchSize = 100)

I didn’t follow all this but you seem to have your head around it, so if you want to submit a Pull Request it might be easier to review.

I didn’t follow all this but you seem to have your head around it, so if you want to submit a Pull Request it might be easier to review.

Breaking Changes https://github.com/codeigniter4/CodeIgni...ng-changes

For this reason, a pull request to move the database drivers to the "Drivers" directory was denied.
This is a simple operation without breaking backward compatibility. But...

Many pitfalls. Some changes may break backward compatibility. 
I myself do not yet fully understand how serious the consequences of the changes can be.

I expect the CI community to share their ideas on this topic.