DbConnect

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This function opens a connection to a database and returns an element that can be used with dbQuery. To disconnect use destroyElement.

[[{{{image}}}|link=]] Note: Connecting and disconnecting many times can have a performance impact on the server. For optimal performance it is recommended that you use dbConnect only once when the resource starts, and share the connection element with the whole script.

Syntax

element dbConnect ( string databaseType, string host [, string username = "", string password = "", string options = "" ] )

OOP Syntax Help! I don't understand this!

Method: Connection(...)

Required Arguments

  • databaseType: The type of database. This can be either sqlite or mysql
  • host: The target to connect to. The format of this depends on the database type.
    • For SQLite it is a filepath to a SQLite database file. If the filepath starts with ":/" then the server's global databases directory is used. The file will be created if it does not exist.
    • For MySQL it is a list of key=value pairs separated by semicolons. Supported keys are:
      • dbname: Name of the database to use e.g. dbname=test
      • host: Host address e.g. host=127.0.0.1
      • port: Host port e.g. port=1234 (optional, defaults to standard MySQL port if not used)
      • unix_socket: Unix socket or named pipe to use (optional)
      • charset: Communicate with the server using a character which is different from the default e.g. charset=utf8 (optional)

Optional Arguments

  • username: Usually required for MySQL, ignored by SQLite
  • password: Usually required for MySQL, ignored by SQLite
  • options : List of key=value pairs separated by semicolons. Supported keys are:
    • share which can be set to 0 or 1. (Default value for SQLite is "share=1", for MySQL is "share=0"). When set to 1, the connection is shared and will be used by other calls to dbConnect with the same host string. This is usually a good thing for SQLite connections, but not so good for MySQL unless care is taken.
    • batch which can be set to 0 or 1. (Default is "batch=1"). When set to 1, queries called in the same frame are automatically batched together which can significantly speed up inserts/updates. The downside is you lose control of the feature that is used to achieve batching (For SQLite it is transactions, for MySQL it is autocommit mode). Therefore, if you use transactions, lock tables or control autocommit yourself, you may want to disable this feature.
    • autoreconnect which can be set to 0 or 1. (Default value "autoreconnect=1"). When set to 1, dropped connections will automatically be reconnected. Note that session variables (incl. SET NAMES), user variables, table locks and temporary tables will be reset because of the reconnection. So if you use these fancy features, you will need to turn autoreconnect off and cope with dropped connections some other way.
    • log which can be set to 0 or 1. (Default value "log=1"). When set to 0, activity from this connection will not be recorded in the database debug log file.
    • tag (Default value "tag=script"). A string which helps identify activity from this connection in the database debug log file.
    • suppress A comma separated list of error codes to ignore. (eg. "suppress=1062,1169").
FROM VERSION 1.5.2 r7972 ONWARDS
    • multi_statements Enable multiple statements (separated by a semi-colon) in one query. Use dbPrepareString when building a multiple statement query to reduce SQL injection risks.

Returns

Returns a database connection element unless there are problems, in which case it return false.

Example

This example opens a connection to a SQLite database file in the current resource

test_db = dbConnect( "sqlite", "file.db" )

This example opens a connection to a SQLite database file in another resource

test_db = dbConnect( "sqlite", ":resname/file.db" )

This example opens a connection to a SQLite database file in the global databases directory

test_db = dbConnect( "sqlite", ":/file.db" )

This example opens a connection to a SQLite database file in a sub directory of the global databases directory

test_db = dbConnect( "sqlite", ":/example/sub/dir/file.db" )

This example opens a connection to a MySQL database called 'frank' at server ip 1.2.3.4 and allows the connection to be shared. Note that changing the database or other connection dependent settings affect all connections that are shared.

test_db = dbConnect( "mysql", "dbname=frank;host=1.2.3.4", "username", "password", "share=1" )

This example opens a connection to a SQLite database is disallows sharing of the connection

test_db = dbConnect( "sqlite", "file.db", "", "", "share=0" )

This example output debug message, if the connection with SQLite database was established or not

test_db = dbConnect( "sqlite", "file.db" )

if test_db then
	outputDebugString( "Connection with database was successfully established." )
else
	outputDebugString( "Connection with database couldn't be established." )
end

Requirements

Minimum supported server 1.1.1-9.03328
Minimum supported client n/a
Note: Using this function requires the resource to have the above minimum version declared in the meta.xml <min_mta_version> section. e.g. <min_mta_version server="1.1.1-9.03328" />

Changelog

Version Description
1.3.1-9.04817 Added options 'log', 'tag' and 'suppress'
1.3.5-9.06386 Added option 'charset'
1.5.2-9.07972 Added option 'multi_statements'

See Also