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This patch adds missing newlines, trims multiple redundant final newlines into a single one, and trims redundant leading newlines. According to POSIX, a line is a sequence of zero or more non-' <newline>' characters plus a terminating '<newline>' character. [1] Files should normally have at least one final newline character. C89 [2] and later standards [3] mention a final newline: "A source file that is not empty shall end in a new-line character, which shall not be immediately preceded by a backslash character." Although it is not mandatory for all files to have a final newline fixed, a more consistent and homogeneous approach brings less of commit differences issues and a better development experience in certain text editors and IDEs. [1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206 [2] https://port70.net/~nsz/c/c89/c89-draft.html#2.1.1.2 [3] https://port70.net/~nsz/c/c99/n1256.html#5.1.1.2
53 lines
1.9 KiB
Plaintext
53 lines
1.9 KiB
Plaintext
PHP Data Objects
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================
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Concept: Data Access Abstraction
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Goals:
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1/ Be light-weight
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2/ Provide common API for common database operations
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3/ Be performant
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4/ Keep majority of PHP specific stuff in the PDO core (such as persistent
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resource management); drivers should only have to worry about getting the
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data and not about PHP internals.
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Transactions and autocommit
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===========================
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When you create a database handle, you *should* specify the autocommit
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behaviour that you require. PDO will default to autocommit on.
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$dbh = new PDO("...", $user, $pass, array(PDO_ATTR_AUTOCOMMIT => true));
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When auto-commit is on, the driver will implicitly commit each query as it is
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executed. This works fine for most simple tasks but can be significantly
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slower when you are making a large number of udpates.
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$dbh = new PDO("...", $user, $pass, array(PDO_ATTR_AUTOCOMMIT => false));
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When auto-commit is off, you must then use $dbh->beginTransaction() to
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initiate a transaction. When your work is done, you then call $dbh->commit()
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or $dbh->rollBack() to persist or abort your changes respectively. Not all
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databases support transactions.
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You can change the auto-commit mode at run-time:
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$dbh->setAttribute(PDO_ATTR_AUTOCOMMIT, false);
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Regardless of the error handling mode set on the database handle, if the
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autocommit mode cannot be changed, an exception will be thrown.
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Some drivers will allow you to temporarily disable autocommit if you call
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$dbh->beginTransaction(). When you commit() or rollBack() such a transaction,
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the handle will switch back to autocommit mode again. If the mode could not
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be changed, an exception will be raised, as noted above.
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When the database handle is closed or destroyed (or at request end for
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persistent handles), the driver will implicitly rollBack(). It is your
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responsibility to call commit() when you are done making changes and
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autocommit is turned off.
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vim:tw=78:et
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