SQLite3::openBlob

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

SQLite3::openBlob — Opens a stream resource to read a BLOB

Description

public SQLite3::openBlob(
    string $table,
    string $column,
    int $rowid,
    string $database = "main",
    int $flags = SQLITE3_OPEN_READONLY
): resource|false

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

SELECT column FROM database.table WHERE 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.

Parameters

table

The table name.

column

The column name.

rowid

The row ID.

database

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.

Return Values

Returns a stream resource, or false on failure.

Changelog

VersionDescription
7.2.0The flags parameter has been added, allowing to write BLOBs; formerly only reading was supported.

Examples

Example #1 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();
?>

The above example will output:

Lorem ipsum

Example #2 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();
?>

The above example will output:

Lorem ipsum
Lorem ipsum
Lorem ipsum