SQLite3::openBlob()

(PHP 5 >= 5.3.0, PHP 7)

Opens a stream resource to read a BLOB

说明

publicSQLite3::openBlob(string $table,string $column,int $rowid[,string $dbname= "main"[,int $flags= SQLITE3_OPEN_READONLY]]): resource

Opens a stream resource to read or write a BLOB, which would be selected by:

SELECT$columnFROM$dbname.$tableWHERE rowid =$rowid

Note: It is not possible to change the size of a BLOB by writing to the stream. Instead, an UPDATE statement has to be executed, possibly using SQLite's zeroblob()function to set the desired BLOB size.

参数

$table

The table name.

$column

The column name.

$rowid

The row ID.

$dbname

The symbolic name of the DB

$flags

Either SQLITE3_OPEN_READONLY or SQLITE3_OPEN_READWRITE to open the stream for reading only, or for reading and writing, respectively.

返回值

Returns a stream resource,或者在失败时返回FALSE.

更新日志

范例

SQLite3::openBlob() example

<?php
$conn = new SQLite3(':memory:');
$conn->exec('CREATE TABLE test (text text)');
$conn->exec("INSERT INTO test VALUES ('Lorem ipsum')");
$stream = $conn->openBlob('test', 'text', 1);
echo stream_get_contents($stream);
fclose($stream); // mandatory, otherwise the next line would fail
$conn->close();
?>

以上例程会输出：

Lorem ipsum

Incrementally writing a BLOB

<?php
$conn = new SQLite3(':memory:');
$conn->exec('CREATE TABLE test (text text)');
$conn->exec("INSERT INTO test VALUES (zeroblob(36))");
$stream = $conn->openBlob('test', 'text', 1, 'main', SQLITE3_OPEN_READWRITE);
for ($i = 0; $i < 3; $i++) {
    fwrite($stream,  "Lorem ipsum\n");
}
fclose($stream);
echo $conn->querySingle("SELECT text FROM test");
$conn->close();
?>

以上例程会输出：

Lorem ipsum
Lorem ipsum
Lorem ipsum