php PDO::FETCH_ASSOC doesnt detect select after backup in stored procedure

问题

I have a stored procedure which make a backup and then return 1 or 0 if there is an error or not something like this:

Create procedure [dbo].[sp_IWBackup]
as
begin
declare @route varchar(500),  @answer int = 0
set nocount on
set @route = 'I:\route'+(replace((replace(convert(varchar, getdate(), 21),':',';')),'.',';'))+'Full.bak'
set @answer = 1
begin try
backup database databasename to disk = @route
end try
begin catch
set @answer = 0
end catch
select @answer as answer
end

In sql it works and return the correct value of @answer.

In php when I try to fetch the execution of the query It doesnt find anything.

public function ExecuteSelectAssoc($sth)
    {
        $r=array('data'=>false,
        'error'=>false,
        'r'=>array());
        try {
            $sth->execute();
            while ($row=$sth->fetch(PDO::FETCH_ASSOC)) {  //error here
                $r['data'] = true;
                $keys = array_keys($row);
                $tmp = array();
                foreach($keys as $key)
                {
                    $tmp[$key] = $row[$key];
                }
                array_push($r['r'], $tmp);
            }
        } catch (PDOException $e) {
            $r['error']=true;
            $r['r'] = $e->getMessage();
        }
        return $r;
    }

Attributes of PDO

public function connectSqlSrv(){
        try{
            $dbCnx = new PDO("sqlsrv:Server=$this->server;Database=$this->db", $this->usr, $this->psw);
            $dbCnx->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            return $dbCnx;
        }
        catch(PDOException $e){
            echo $e;
            die();
            return null;
        }
    }

And I get this error:

r: "SQLSTATE[IMSSP]: The active result for the query contains no fields."

And I expect : Answer: 1

回答1:

Explanations:

The reason for your error is that BACKUP DATABASE returns informational messages and your stored procedure has multiple result sets. I reproduced your error with a test script (although in your question I can't see how you prepare your stored procedure). You may try with one of the following solutions (I've made simple scripts, which you can easily implement in your functions).

call PDOStatement::nextRowset to fetch each result set (two additional calls in this case)
use an OUTPUT parameter in your stored procedure. In this case you need to fetch all result sets and after that to get the value of the output parameter.

Solution 1:

Stored procedure:

create procedure [dbo].[sp_IWBackup]
as
begin
    declare 
       @route varchar(500),  
       @answer int = 0
    set nocount on

    set @route = 'I:\route'+(replace((replace(convert(varchar, getdate(), 21),':',';')),'.',';'))+'Full.bak'
    set @answer = 1

    begin try
        backup database databasename to disk = @route
    end try
    begin catch
        set @answer = 0
    end catch

    select @answer as answer
end

PHP:

<?php
$server   = 'server\instance,port';
$database = 'database';
$uid      = 'uid';
$pwd      = 'pww';

try {
    $dbh = new PDO("sqlsrv:server=$server;Database=$database", $uid, $pwd);
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch( PDOException $e ) {
    die("Error connecting to SQL Server. ".$e->getMessage());
}

try {
    $sql = "{CALL sp_IWBackup}";
    $stmt = $dbh->prepare($sql);
    $stmt->execute();
    $stmt->nextRowset();
    $stmt->nextRowset();
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
        foreach ($row as $key => $value) {
            echo $key.": ".$value."<br>";
        };
    }
} catch( PDOException $e ) {
    die( "Error executing stored procedure: ".$e->getMessage());
}
$stmt = null;

$dbh = null;
?>

Solution 2:

Stored procedure:

create procedure [dbo].[sp_IWBackupOut]
    @answer int OUTPUT
as
begin
    declare 
        @route varchar(500)
    set nocount on

    set @route = 'I:\route'+(replace((replace(convert(varchar, getdate(), 21),':',';')),'.',';'))+'Full.bak'
    set @answer = 1

    begin try
        backup database databasename to disk = @route
    end try
    begin catch
        set @answer = 0
    end catch
end

PHP:

<?php
$server   = 'server\instance,port';
$database = 'database';
$uid      = 'uid';
$pwd      = 'pww';

try {
    $dbh = new PDO("sqlsrv:server=$server;Database=$database", $uid, $pwd);
    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch( PDOException $e ) {
    die("Error connecting to SQL Server. ".$e->getMessage());
}

try {
    $sql = "{CALL sp_IWBackupOut (?)}";
    $stmt = $dbh->prepare($sql);
    $answer = -1;
    $stmt->bindParam(1, $answer, PDO::PARAM_INT|PDO::PARAM_INPUT_OUTPUT, PDO::SQLSRV_PARAM_OUT_DEFAULT_SIZE);
    $stmt->execute();
    do {
    } while ($stmt->nextRowset());
    echo "answer: ".$answer;
} catch( PDOException $e ) {
    die( "Error executing stored procedure: ".$e->getMessage());
}
$stmt = null;

$dbh = null;
?>

来源：https://stackoverflow.com/questions/56433567/php-pdofetch-assoc-doesnt-detect-select-after-backup-in-stored-procedure

标签

php

sql

sql-server

pdo

backup