Updated in 1.6.0-9.22497

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

Tip

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.

Note

In MySQL 8.0 and later, you can choose between caching_sha2_password, sha256_password, or mysql_native_password for password management.

• If you opt for caching_sha2_password or sha256_password, SSL is not mandatory but recommended for secure authentication.
• If you choose mysql_native_password, you can set it as the default authentication plugin:
  • In the mysqld.cnf configuration file, by adding or modifying the following line: default-authentication-plugin=mysql_native_password.
  • Using SQL queries (e.g., ALTER USER).
  • In PHPMyAdmin (via the user settings page).

Please note that starting with MySQL 9.0, mysql_native_password will no longer be available, and only caching_sha2_password and sha256_password will be supported.

Note

Under certain platforms, for example on Unix-based OSes like Linux, using this function could fail with a debug warning containing [Could not connect] accompanied by a prior debug error explaining the problem. In that case you should check the Server Manual to see if you have missed any recommended (best-effort) steps for server set-up.

OOP Syntax Help! I don't understand this!

• Constructor: Connection (...)

Syntax

db-connection dbConnect ( string databaseType, string host, [ string username = "", string password = "", string options = "" ] )

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=3306 (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

NOTE: When using optional arguments, you might need to supply all arguments before the one you wish to use.

• username (default: ""): Usually required for MySQL, ignored by SQLite
• password (default: ""): Usually required for MySQL, ignored by SQLite
• options (default: ""): 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").
  • 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.
  • queue: Name of the queue to use. (Default value for SQLite is "sqlite", for MySQL default is the host string from the host argument). Asynchronous database queries in the same queue are processed in order, one at a time. Any name can be used.
  • use_ssl: which can be set to 0 or 1. (Default value is 0), ignored by SQLite.
  • get_server_public_key: which can be set to 0 or 1. (Default value is 1), ignored by SQLite. When set to 1, this enables the client to request from the server the public key required for RSA key pair-based password exchange. This option applies to clients that authenticate with the `caching_sha2_password`` authentication plugin.

Returns

• db-connection: db connection handle

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

Code Examples

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 (OOP)

server - SQLite

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

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

server - SQLite

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

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

server - SQLite

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

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

server - SQLite

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")

server - MySQL

This example opens a connection to a MySQL database called 'frank' at server ip 1.2.3.4 using utf8 character set 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;charset=utf8", "username", "password", "share=1")

server - SQLite

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

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

server - SQLite

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

local 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

server - MySQL

The folowing example shows how you could approach a common resource for database operations with exported functions.

function connect()
    DBConnection = dbConnect("mysql", "dbname=DBNAME;host=HOST;charset=utf8", "USERNAME", "PASSWORD")
    if (not DBConnection) then
        outputDebugString("Error: Failed to establish connection to the MySQL database server")
    else
        outputDebugString("Success: Connected to the MySQL database server")
    end
end

addEventHandler("onResourceStart", resourceRoot, connect)

function query(...)
    local queryHandle = dbQuery(DBConnection, ...)
    if (not queryHandle) then return nil end
    local rows = dbPoll(queryHandle, -1)
    return rows
end

function execute(...)
    local queryHandle = dbQuery(DBConnection, ...)
    local result, numRows = dbPoll(queryHandle, -1)
    return numRows
end

function getDBConnection() return DBConnection end

server - SQLite

OOP Required

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

local test_db = Connection("sqlite", "file.db")

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

Changelog

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.

1.5.4-9.11138

Added option queue.

1.6.0-9.22396

Added option use_ssl.

1.6.0-9.22497

Added option get_server_public_key.

See Also

Database Functions

• dbConnect
• dbExec
• dbFree
• dbPoll
• dbPrepareString
• dbQuery
• executeSQLQuery

Reference

• Scripting Functions