MySql: jeśli wartość istnieje UPDATE jeszcze INSERT

Question

Mam trochę kodu, który wygląda tak. W tabeli znajduje się również pole autorekrecji, które muszę zachować (jest używane w innych tabelach). Chciałbym uprościć i zoptymalizować ten kod.

$query ="SELECT * FROM models WHERE col1 = 'foo'"; 
$testResult = mysql_query($query) or die('Error, query failed');  

if(mysql_fetch_array($testResult) == NULL){ 
    //insert... 
    $query ="INSERT INTO models (col1, col2, col3) 
    VALUES ('foo', 'bar', 'alph')"; 
    $result = mysql_query($query) or die('Error, query failed'); 
}else{ 
    //update... 
    $query = "UPDATE models 
     SET col1='foo', col2='bar', col3='alph' 
     WHERE col1='foo' AND col2='bar'"; 
     $result = mysql_query($query) or die('Error, query failed');   
} 

Edytuj: Identyfikator klucza głównego to pole, które jest automatycznie zwiększane. Nigdy nie chcę tego zmieniać. Jednak gdy inne pola są/są duplikowane, to wtedy chcę zaktualizować ten rekord.

Answer 1

Jak o WYMIENIĆ W:

REPLACE INTO models 
(col1, col2, col3) 
VALUES 
('foo', 'bar', 'alpha') 

Zakładając, że col1 jest kluczem podstawowym, jeśli wiersz o wartości "foo" już istnieje, zaktualizuje dwie pozostałe kolumny. W przeciwnym razie wstawi nowy wiersz.

Answer 2

można spróbować użyć "INSERT ... ON duplikat KEY UPDATE" składnia

http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row is performed. For example, if column a is declared as UNIQUE and contains the value 1, the following two statements have identical effect: 

INSERT INTO table (a,b,c) VALUES (1,2,3) 
    ON DUPLICATE KEY UPDATE c=c+1; 

UPDATE table SET c=c+1 WHERE a=1; 
The ON DUPLICATE KEY UPDATE clause can contain multiple column assignments, separated by commas. 

With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row is inserted as a new row and 2 if an existing row is updated. 

If column b is also unique, the INSERT is equivalent to this UPDATE statement instead: 

UPDATE table SET c=c+1 WHERE a=1 OR b=2 LIMIT 1; 
If a=1 OR b=2 matches several rows, only one row is updated. In general, you should try to avoid using an ON DUPLICATE KEY clause on tables with multiple unique indexes. 

You can use the VALUES(col_name) function in the UPDATE clause to refer to column values from the INSERT portion of the INSERT ... UPDATE statement. In other words, VALUES(col_name) in the UPDATE clause refers to the value of col_name that would be inserted, had no duplicate-key conflict occurred. This function is especially useful in multiple-row inserts. The VALUES() function is meaningful only in INSERT ... UPDATE statements and returns NULL otherwise. Example: 

INSERT INTO table (a,b,c) VALUES (1,2,3),(4,5,6) 
    ON DUPLICATE KEY UPDATE c=VALUES(a)+VALUES(b); 
That statement is identical to the following two statements: 

INSERT INTO table (a,b,c) VALUES (1,2,3) 
    ON DUPLICATE KEY UPDATE c=3; 
INSERT INTO table (a,b,c) VALUES (4,5,6) 
    ON DUPLICATE KEY UPDATE c=9; 
If a table contains an AUTO_INCREMENT column and INSERT ... UPDATE inserts a row, the LAST_INSERT_ID() function returns the AUTO_INCREMENT value. If the statement updates a row instead, LAST_INSERT_ID() is not meaningful. However, you can work around this by using LAST_INSERT_ID(expr). Suppose that id is the AUTO_INCREMENT column. To make LAST_INSERT_ID() meaningful for updates, insert rows as follows: 

INSERT INTO table (a,b,c) VALUES (1,2,3) 
    ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id), c=3; 
The DELAYED option is ignored when you use ON DUPLICATE KEY UPDATE. 

Answer 3

dla MySQL 5.0 + Zastosowanie: INSERT ON DUPLICATE KEY UPDATE

http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

Answer 4

Wystarczy zaktualizować kol. 3 w duplikacie. Właśnie o to prosisz.

INSERT INTO models (col1, col2, col3) 
VALUES ('foo', 'bar', 'alpha') 
ON DUPLICATE KEY UPDATE col3='alpha';