php教程

Basic usage

Example #1 DBA example

<?php

$id 
dba_open("/tmp/test.db""n""db2");

if (!
$id) {
    echo 
"dba_open failed\n";
    exit;
}

dba_replace("key""This is an example!"$id);

if (
dba_exists("key"$id)) {
    echo 
dba_fetch("key"$id);
    
dba_delete("key"$id);
}

dba_close($id);
?>

DBA is binary safe and does not have any arbitrary limits. However, it inherits all limits set by the underlying database implementation.

All file-based databases must provide a way of setting the file mode of a new created database, if that is possible at all. The file mode is commonly passed as the fourth argument to dba_open() or dba_popen().

You can access all entries of a database in a linear way by using the dba_firstkey() and dba_nextkey() functions. You may not change the database while traversing it.

Example #2 Traversing a database

<?php

// ...open database...

$key dba_firstkey($id);

while (
$key !== false) {
    if (
true) {          // remember the key to perform some action later
        
$handle_later[] = $key;
    }
    
$key dba_nextkey($id);
}

foreach (
$handle_later as $val) {
    
dba_delete($val$id);
}

?>

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