PrimaryReplicaTrait
- Type
- Trait
- Namespace
- craft\db
- Implemented by
- craft\db\Connection
- Since
- 3.4.25
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# Public Methods
| Method | Description |
|---|---|
| getPrimary() | Returns the currently active primary connection. |
| getPrimaryPdo() | Returns the PDO instance for the currently active primary connection. |
| getReplica() | Returns the currently active replica connection. |
| getReplicaPdo() | Returns the PDO instance for the currently active replica connection. |
| usePrimary() | Executes the provided callback by using the primary connection. |
# getPrimary()
Returns the currently active primary connection.
If this method is called for the first time, it will try to open a primary connection.
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Returns
craft\db\Connection, null (opens new window) – The currently active primary connection. null is returned if no primary connection
is available.
# getPrimaryPdo()
Returns the PDO instance for the currently active primary connection.
This method will open the primary DB connection and then return \craft\db\pdo.
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Returns
PDO (opens new window) – The PDO instance for the currently active primary connection.
# getReplica()
Returns the currently active replica connection.
If this method is called for the first time, it will try to open a replica connection when \craft\db\enableReplicas
is true.
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Arguments
$fallbackToPrimary(boolean (opens new window)) – Whether to return the primary connection if no replica connections are available.
Returns
craft\db\Connection, null (opens new window) – The currently active replica connection. null is returned if no replica connections
are available and $fallbackToPrimary is false.
# getReplicaPdo()
Returns the PDO instance for the currently active replica connection.
When \craft\db\enableReplicas is true, one of the replicas will be used for read queries, and its PDO instance
will be returned by this method.
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Arguments
$fallbackToPrimary(boolean (opens new window)) – Whether to return the primary PDO if no replica connections are available.
Returns
PDO (opens new window), null (opens new window) – The PDO instance for the currently active replica connection. null is returned if no
replica connections are available and $fallbackToPrimary is false.
# usePrimary()
Executes the provided callback by using the primary connection.
This method is provided so that you can temporarily force using the primary connection to perform DB operations even if they are read queries. For example,
$result = $db->usePrimary(function ($db) {
return $db->createCommand('SELECT * FROM user LIMIT 1')->queryOne();
});
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Arguments
$callback(callable (opens new window)) – A PHP callable to be executed by this method. Its signature isfunction (Connection $db). Its return value will be returned by this method.
Returns
mixed – The return value of the callback
Throws
- Throwable (opens new window)
if there is any exception thrown from the callback