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CXVIII. SQLite Functions
This is an extension for the SQLite Embeddable SQL Database Engine.
SQLite is a C library that implements an embeddable SQL database engine.
Programs that link with the SQLite library can have SQL database access
without running a separate RDBMS process.
SQLite is not a client library used to connect to a big database server.
SQLite is the server. The SQLite library reads and writes directly to and from
the database files on disk.
Read the INSTALL file, which comes with the package. Or just use the PEAR
installer with "pear install sqlite".
SQLite itself is already included, You do not need to install
any additional software.
Windows users may download the DLL version of the SQLite extension here:
(php_sqlite.dll).
In PHP 5, the SQLite extension and the engine itself are bundled and
compiled by default.
Windows installation for unprivileged accounts:
On Windows operating systems, unprivileged accounts don't have the
TMP environment variable set by default. This will
make sqlite create temporary files in the windows directory, which is
not desirable. So, you should set the TMP environment
variable for the web server or the user account the web server is
running under. If Apache is your web server, you can accomplish this via
a SetEnv directive in your httpd.conf file. For
example:
If you are unable to establish this setting at the server
level, you can implement the setting in your script:
The setting must refer to a directory that the web server
has permission to create files in and subsequently write
to and delete the files it created.
Otherwise, you may receive the following error message:
malformed database schema -
unable to open a temporary database file for storing temporary tables
In order to have these functions available, you must compile PHP with
SQLite support, or load the SQLite extension dynamically from your
php.ini.
There are two resources used in the SQLite Interface. The first one is the
database connection, the second one the result set.
Poniższe stałe są zdefiniowane w tym rozszerzeniu i stają się dostępne, gdy
rozszerzenie jest dokompilowane do PHP, lub załadowane dynamicznie przy starcie.
The functions sqlite_fetch_array() and
sqlite_current() use a constant for
the different types of result arrays. The following constants are
defined:
SQLite result type constants - SQLITE_ASSOC
(int)
Columns are returned into the array having the field name as the array
index.
- SQLITE_BOTH
(int)
Columns are returned into the array having both a numerical index
and the field name as the array index.
- SQLITE_NUM
(int)
Columns are returned into the array having a numerical index to the
fields. This index starts with 0, the first field in the result.
A number of functions may return status codes. The following constants are
defined:
SQLite status code constants - SQLITE_OK
(int)
Successful result.
- SQLITE_ERROR
(int)
SQL error or missing database.
- SQLITE_INTERNAL
(int)
An internal logic error in SQLite.
- SQLITE_PERM
(int)
Access permission denied.
- SQLITE_ABORT
(int)
Callback routine requested an abort.
- SQLITE_BUSY
(int)
The database file is locked.
- SQLITE_LOCKED
(int)
A table in the database is locked.
- SQLITE_NOMEM
(int)
Memory allocation failed.
- SQLITE_READONLY
(int)
Attempt to write a readonly database.
- SQLITE_INTERRUPT
(int)
Operation terminated internally.
- SQLITE_IOERR
(int)
Disk I/O error occurred.
- SQLITE_CORRUPT
(int)
The database disk image is malformed.
- SQLITE_NOTFOUND
(int)
(Internal) Table or record not found.
- SQLITE_FULL
(int)
Insertion failed because database is full.
- SQLITE_CANTOPEN
(int)
Unable to open the database file.
- SQLITE_PROTOCOL
(int)
Database lock protocol error.
- SQLITE_EMPTY
(int)
(Internal) Database table is empty.
- SQLITE_SCHEMA
(int)
The database schema changed.
- SQLITE_TOOBIG
(int)
Too much data for one row of a table.
- SQLITE_CONSTRAINT
(int)
Abort due to constraint violation.
- SQLITE_MISMATCH
(int)
Data type mismatch.
- SQLITE_MISUSE
(int)
Library used incorrectly.
- SQLITE_NOLFS
(int)
Uses of OS features not supported on host.
- SQLITE_AUTH
(int)
Authorized failed.
- SQLITE_ROW
(int)
Internal process has another row ready.
- SQLITE_DONE
(int)
Internal process has finished executing.
Represents an opened SQLite database.
query - Execute a query queryExec - Execute a result-less query arrayQuery - Execute a query and return the result as an array singleQuery - Execute a query and return either an array for one single column or the value of the first row unbufferedQuery - Execute an unbuffered query lastInsertRowid - Returns the rowid of the most recently inserted row changes - Returns the number of rows changed by the most recent statement createAggregate - Register an aggregating UDF for use in SQL statements createFunction - Register a UDF for use in SQL statements busyTimeout - Sets or disables busy timeout duration lastErorr - Returns the last error code of the most recently encountered error fetchColumnTypes - Return an array of column types from a particular table
Represents a buffered SQLite result set.
fetch - Fetches the next row from the result set as an array fetchObject - Fetches the next row from the result set as an object fetchSingle - Fetches the first column from the result set as a string fetchAll - Fetches all rows from the result set as an array of arrays column - Fetches a column from the current row of the result set numFields - Returns the number of fields in the result set fieldName - Returns the name of a particular field in the result set current - Fetches the current row from the result set as an array key - Return the current row index next - Seek to the next row number valid - Returns whether more rows are available rewind - Seek to the first row number of the result set prev - Seek to the previous row number of the result set hasPrev - Returns whether or not a previous row is available numRows - Returns the number of rows in the result set seek - Seek to a particular row number
Represents an unbuffered SQLite result set. Unbuffered results sets are sequential, forward-seeking only.
fetch - Fetches the next row from the result set as an array fetchObject - Fetches the next row from the result set as an object fetchSingle - Fetches the first column from the result set as a string fetchAll - Fetches all rows from the result set as an array of arrays column - Fetches a column from the current row of the result set numFields - Returns the number of fields in the result set fieldName - Returns the name of a particular field in the result set current - Fetches the current row from the result set as an array next - Seek to the next row number valid - Returns whether more rows are available
Na działanie tych funcji wpływają ustawienia zawarte w pliku
php.ini.
Tabela 1. SQLite Opcje konfigurowalne | Nazwa | Domyślne | Zmienialne | Changelog |
|---|
| sqlite.assoc_case | "0" | PHP_INI_ALL | Available since PHP 5.0.0. |
Szczegóły i definicje dotyczące stałych
PHP_INI_* znajdują się w rozdziale Dodatek H.
Oto krótkie wyjaśnienie dyrektyw
konfiguracji.
- sqlite.assoc_case
int
Whether to use mixed case (0), upper case
(1) or lower case (2) hash
indexes.
This option is primarily useful when you need compatibility with other
database systems, where the names of the columns are always returned as
uppercase or lowercase, regardless of the case of the actual field names
in the database schema.
The SQLite library returns the column names in their natural case (that
matches the case you used in your schema). When
sqlite.assoc_case is set to 0
the natural case will be preserved. When it is set to
1 or 2, PHP will apply case
folding on the hash keys to upper- or lower-case the keys, respectively.
Use of this option incurs a slight performance penalty, but is MUCH
faster than performing the case folding yourself using PHP script.
User Contributed Notesheinemann.juergen AT t-online.de
11-Nov-2005 06:53
Simple Example for using SQLite for small Buffering Clipboard ;)
<?php
final class SQLiteClipboard
{
private $SQL;
private $DB = "Clipboard.sqlite";
private $TB = "Clipboard";
private $ID = "ID";
private $PA = "PARAM";
private $VA = "VAL";
function __construct( $path )
{
$this->DB = chop( $path . "/" . $this->DB );
$this->sql_init();
}
private function sql_init()
{
$this->SQL = new SQLiteDatabase( $this->DB, 0660 );
if ( ! file_exists( $this->DB ) )
die( "Permission Denied!" );
$q = $this->SQL->query("PRAGMA table_info(" . $this->TB . ")");
if ( $q->numRows() == 0 ) {
$this->SQL->query( "CREATE TABLE " . $this->TB . " ( " . $this->ID . " INTEGER PRIMARY KEY, " . $this->PA . " CHAR(255), " . $this->VA . " CHAR(255) );" );
}
}
private function sql_check( $p )
{
$o = null;
$q = $this->SQL->query( "SELECT " . $this->ID . " FROM " . $this->TB . " WHERE ( " . $this->PA . "='$p' ) ORDER BY " . $this->ID . " LIMIT 1" );
while( $q->valid() ) {
$r = $q->current();
return $r[$this->ID];
$q->next();
}
return false;
}
public function __get( $p )
{
$q = $this->SQL->query( "SELECT " . $this->VA . " FROM " . $this->TB . " WHERE ( " . $this->PA . "='$p' ) ORDER BY " . $this->ID );
while( $q->valid() ) {
$r = $q->current();
$o = $r[$this->VA];
$q->next();
}
return $o;
}
public function __set( $p, $v )
{
if ( $this->sql_check( $p ) && ! empty( $v ) )
return $this->SQL->query( "UPDATE " . $this->TB . " SET " . $this->VA . "='$v' WHERE ( " . $this->PA . "='$p' );" );
elseif ( ! $this->sql_check( $p ) && ! empty( $v ) )
return $this->SQL->query( "INSERT INTO " . $this->TB . " ( " . $this->PA . ", " . $this->VA . " ) VALUES ('$p', '$v' );" );
elseif ( $this->sql_check( $p ) && empty( $v ) )
return $this->SQL->query( "DELETE FROM " . $this->TB . " WHERE ( " . $this->PA . "='$p' );" );
else
return false;
}
} ?>
01-Sep-2005 01:21
A function to check whether a table exists:
<?php
function sqlite_table_exists(&$sqlite, $table)
{
$result = $sqlite->query("SELECT name FROM sqlite_master WHERE type='table' AND name='$table'");
return $result->numRows() > 0;
}
?>
bens at effortlessis dot com
14-Jul-2005 08:37
Sqlite by default allows for foreign keys, but doesn't enforce them.
I found a nice article on how to enforce foreign keys at http://www.justatheory.com/computers/databases/sqlite/
It would be nice if this could be handled with a wrapper class, so that adding foreign keys is done thru a wrapper API to automate the generation of the necessary enforcement triggers. If nobody's done this by the time I start coding against SqlLite/PHP5 in 6-12 months, I'll write one myself, possibly by modifying "jon at jenseng dot com"s alter table wrapper
Anyway, it's not PHP specific, but anybody using Sqlite really should know this!
Stephen Leaf
30-Jun-2005 02:58
I think it would be good to point out that currently (as of 5.0.4) this extention does not support SQLite 3 databases.
So if your getting an error message like:
Error: file is encrypted or is not a database
That is why.
bart at mediawave dot nl
18-Apr-2005 04:30
SELECT tablename.columnname FROM table;
will cause SQLite to return an array having tablename.field_name as the array index. (e.g. $result['tablename.field_name'])
To let SQLite return an array having only field_name as the array index (e.g. $result['field_name']) you can issue a 'PRAGMA short_column_names = 1' query:
sqlite_query($connection_id, 'PRAGMA short_column_names = 1');
This behaviour is more consistent with the other database extensions.
For a full list of all pragmas visit: http://sqlite.org/pragma.html
dotwho at NOSPAM dot mac dot com
10-Feb-2005 03:03
This may have been obvious to others, but I had a tough time finding the info.
The default location for the actual database file is the same location of the php doc that created the database. You can alter this behavior by specifying the full path in the creation call:
<php
$db = sqlite_open("/absolute/path/my_sqlite.db");
?>
Note that if you used the default location, the db file may be served up by the webserver if it is in a the http document path. This is obviously a security risk that should be avoided.
//Max
hunreal+php at gmail dot com
16-Jan-2005 05:42
Check the db/table if exist
$db_name='db';
$db=new SQLiteDatabase($db_name, 0666, $error);
if ($error) exit($error);
$q=$db->query("PRAGMA table_info(test)");
if ($q->numRows()!=2) {
if (!@$db->queryexec("
CREATE TABLE test (
id INTEGER NOT NULL PRIMARY KEY,
text VARCHAR ( 255 ) NOT NULL
)")
) exit ("Create SQLite Database Error\n");
}
nicolas dot toniazzi at free dot fr
16-Nov-2004 04:24
The same in 3 lines.
<?php
function sqlite_table_exists($db,$mytable) {
$result = sqlite_query($db,"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='$mytable'");
$count = intval(sqlite_fetch_single($result));
return $count > 0;
}
?>
alexs at alphacomolex dot info
29-Oct-2004 12:41
the OO version.
<?php
function sqlite_table_exists($db,$mytable) {
$result = $db->query("SELECT name FROM sqlite_master WHERE type='table'");
$tables = $result->fetchAll();
if (count($tables) == 0) {
return FALSE ;
}
foreach ($tables as $table) {
if ($table['name'] == $mytable) {
return(TRUE);
}
}
return(FALSE);
}
?>
artooro at gmail dot com
22-Oct-2004 03:26
If you need to check if a table exists, you can use a function like this:
<?php
function sqlite_table_exists($mytable) {
$db = sqlite_open('mydb.sqlite', 0666, $sqliteerror);
$query = sqlite_query($db, "SELECT name FROM sqlite_master WHERE type='table'");
$tables = sqlite_fetch_array($query);
if ($tables != '') {
foreach ($tables as $table) {
if ($table == $mytable) {
return("TRUE");
}
else {
return("FALSE");
}
}
}
else {
return("FALSE");
}
}
?>
A function like this could be used to create the table if it's not already created, etc.
j-pieper at NOSPAM dot web dot de
19-Oct-2004 12:18
If you want to create a table in your database which should have an integer primary key, you cannot declare the row like this:
id int(16) primary key
or
id integer(16) primary key
When you declare it like this it could be that the id isn
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