How to use the select method of the Model class in PHP?

The previous article introduced to you "How to implement the database query method in PHP? 》, this article continues to introduce to you how to use the select method of the Model class in PHP? It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

Model class select method:

To write the select method, first we define a function, and then we need to splice SQL statements in the select, and we also Will call

//filed method

//table method

/ /where method

//group method

/ /having method

//order method

//limit

method waits for these methods, and then passes the parameters to us, in order to proceed infinitely To replace, we first write a SQL statement with placeholders. The variables we pass will be passed to the array we defined. Then we will replace the above placeholders with the corresponding values ​​​​in options. , we can directly use str_repiace for direct replacement,

function select( )
{
//先预写-一个带有占位符的sql语句
$sql
='select %FIELD% from %TABL E% %WHERE%
%GROUP% %HAVING% %ORDER% %L IMIT%' ;
//将options中对应的值依次的替换.上面的占位符
$sql = str_replace(
['%FIELD%'，'%TABLE%'， '%WHERE%'，'%GROUP%'
)%HAVING%''%ORDER%''%LIMIT%'],
[$this- >options['field'], $this - >options [ 'table'], $this- >options['where'], $this
->option's[' group'], $this->options ['having'], $this->options[ 'order']，$this->options['limit']],
subject)
}

When we use the above method, it does not matter what the order we use, because after we call, the parameters passed by the data will Pass it to the array. After we splice it, continue to save a SQL statement:

$this->sq1 = $sql;
$this->sq1 = $sql;

and then execute the SQL statement:

returni $this->query($sql);

For query:

//获取SQL语句
function query()
{
}

For exec:

function_ get($name)
{
if($name ==
1
sql') {
return $this ->sq1;
}
return false;
}

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