README

Purpose

A convenience wrapper over PDO that has lazy loading and singletons, allows for backup connections, and attempts to reconnect on connection loss

Appetizer

The intent of the Db class is to reduce the amount of time coding common database operations.

Output

One common issue is formatting. Say I want only a column in a database, and I want it as an array

$db->column('select name from user');

Say I want an array of rows, but I want it keyed on the user id

$db->column_key('id', 'select name from user');

What if I just want a single, non array value of some column, in some record?

$db->value('select name from user where id = 2');

Special Query

For a query, the normal ['id'=> 2] array does not suit for situations of non-equal operators. What if I wanted name is null or id > 10? This is built in to Db

$table = 'users';
$query = [
	'id ? >' => 10, # '?' indicates the operator will appear next
	'name ? is not' => null # null values are presented to the database as string NULL
	'disabled' => null,
	'gender' => 'm'
	':last_login' => 'DATE()' # the ":" preface indicates not to escape the value part
];
$db->rows($table, $query)

This will result in SQL like

SELECT * FROM `x` WHERE
`id` > 10 AND
`name` is not null AND
`disabled` is null AND
`gender` = 'm' AND
`last_login` = DATE()

This special type of array interpretation allows the full set of complex query filters to be maintained in an array, instead of having to construct the SQL piece by piece.

The query array can be used on all of the methods

$db->delete($table, $query);
$db->insert($table, $query);
$db->insert_ignore($table, $query);
$db->insert_update($table, $query);
$db->replace($table, $query);
$db->rows($table, $query);
$db->row($table, $query);
$db->value($table, $query);
# ...

Optional Use

There are a variety of ways you can present your SQL. Db supports

• prepared statements
• plain txt
• query array and positional arguments ($table, $query, $select)

$db->row(['select name from user where id = :id', [':id'=>1]]);
$db->row('select name from user where id = `1`');
$db->row('user', ['id'=>1], 'name');

Use

Connecting

use \Grithin\Db;

$dbConfig = ['user'=>'root',
	'password'=>'',
	'database'=>'feed',
	'host'=>'localhost',
	'driver'=>'mysql'	];


$db = Db::init('main', $dbConfig);

$dbConfig = ['user'=>'root',
	'password'=>'',
	'database'=>'test',
	'host'=>'localhost',
	'driver'=>'mysql'	];


$db2 = Db::init('secondary', $dbConfig);

The first argument to init is the name of the singleton instance (see SingletonDefault or SDLL class in phpbase).

When Db is called statically, it defaults to the primary singleton instance, which is usually the first initialised.

$db1 = Db::init(null, $config1);
Db::row('user',$id); # on $db1 instance
$db1->row('user',$id);

$db2 = Db::init('secondary', $config2);
Db::row('user',$id); # still on $db1 instance
$db2->row('user',$id);

Db::primary_set('secondary');
Db::row('user',$id); # on $db2 instance

If you want a instance variable for the primary singleton (the singleton default), you can get it

$db =  Db::primary();

This is useful for looped code (since there is overhead in using static methods).

You can also get an instance by name

$db = Db::$instances['main'];

Basic Use

There are two flavors of use

1. quoted queries
2. prepared statements

Query

Quoting

All user input placed in raw sql should be quoted or conformed. You can quote with

'select * from user where id = '.Db::quote($id);

You can also quote database identities, with

'select '.Db::identity_quote('table.max').' from '.Db::identity_quote('table').' where id = 1'

This is sometimes useful when the identity has a name conflicting with a reserved database identity

SQL

Db::value('select name from user where id = 1');
#> 'bob'

Db::row('select * from user'); # will append a `limit 1`
#> ['id'=>'1','name'=>'bob']

Db::rows('select * from user');
#> [['id'=>'1','name'=>'bob'], ['id'=>'2','name'=>'bill']]

Db::column('select name from user');
#> ['bob','bill']

Db::columns('select * from user');
#> [['1','bob'],[['2','bill']]

list($id, $name) =  Db::enumerate('select id, name from user');

Db::column_key('id','select id, name from user');
#> ['1'=>'bob', '2'=>'bill']
# if more than 2 columns are selected, the key points to another array, ex:
#	#> ['1'=>['name'=>'bob', 'gender'=>'m'], '2'=>['name'=>'bill', 'gender'=>'m']]

Shortcuts

Short cut parameters are automatically quoted if necessary

Db::row('user',1); # select * from user where id = 1
Db::row('user',['id'=>1]); # select * from user where id = 1

Db::insert('user',['name'=>'jill']);

Db::insert_ignore('user',['name'=>'jill']);
Db::insert_update('user',['id'=>'3','name'=>'jill']);

Db::replace('user',['id'=>'2', 'name'=>'jill']);

Db::update('user',['name'=>'jan'], ['id'=>3]);

Db::delete('user',1);
Db::delete('user',['id'=>1]);
Db::delete('user',['id?>'=>1]);

There are many additional helper functions like the above. I recommended looking through the code. Create a github issue if you require one to be further documented.

Shortcut Magic

Using a custom comparater

# `>` is used
Db::row('user', ['id?>'=>1]); # select * from user where id > 1

There is various behavior based on these rules:

• if key starts with '"', the unescaped value is taken as entire where line
  • ex: ['" anything after the " is not used':'1=1']
• if "?" is in the key, the part after the "?" will serve as the "equator", ("bob?<>"=>'sue') -> "bob <> 'sue'"
• if key starts with ":", value is not escaped
• if value === null, set value to unescaped "null"
• if value set to unescaped "null", and if within a "where" helper function, and comparater is '=', prefix with 'is '.

Prepared Statements

The exec function is overloaded to accept three forms. The end result of the forms is to have one joined sql string and one merged variable array.

• single array (['sql',$var_array,'sql']):
• as params ($sql1, $var_array1, $sql2, $var_array2, $var_array3 )

$pdo_statement = $db->exec(['select * from user where id = :id',[':id'=>1]])
$pdo_statement = $db->exec('select * from','user where id = :id',[':id'=>1],'and id = :id2',[':id2'=>1] );

You can either use pdo statment methods, or you can use Db helper functions. Most of the query based functions have corresponding methods prefixed with as_

$pdo_statement = $db->exec(['select * from user where id = :id',[':id'=>1]])
$db->as_row($pdo_statement);
$db->as_rows($pdo_statement);
$db->as_value($pdo_statement);