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Version: latest - a1.11.0 ⚖️

💾 Database

The Database entity provides programmers a way to access SQL databases easily through scripting.

info

🟦 Authority: This class can only be spawned on Server.

tip

Currently nanos world supports SQLite, MySQL and PostgreSQL out of the box.

Example

-- Creates a SQLite connection, using a local file called 'database_filename.db'
local sqlite_db = Database(DatabaseEngine.SQLite, "db=database_filename.db timeout=2")

-- Creates a table
sqlite_db:Execute([[
CREATE TABLE IF NOT EXISTS test (
id INTEGER,
name VARCHAR(100)
)
]])

-- Executes a Query
sqlite_db:Execute("INSERT INTO test VALUES (1, 'amazing')", function(affected_rows)
Package.Log("Affected Rows: " .. tostring(affected_rows))
-- Will output: 1
end)

-- Selects the data
sqlite_db:Select("SELECT * FROM test", function(rows)
Package.Log(NanosUtils.Dump(rows))
-- Will output a table with all data from 'test'
end)

-- Selects the data with filter
sqlite_db:Select("SELECT * FROM test WHERE name = :0", function(rows)
Package.Log(NanosUtils.Dump(rows))
-- Will output a table with all data from 'test' where name matches 'amazing'
end, 'amazing')
tip

All requests are thread safe! 🥳

Constructor Parameters

TypeNameDefaultDescription
DatabaseEnginedatabase_engineDatabase Engine
stringconnection_stringConnection String used to create and connect to the database
numberpool_size10Size of the connection pool when calling several queries simultaneously

Functions

ReturnsNameDescription
FecharCloses the Database
ExecuteExecute a query asyncronously
ExecuteSyncExecute a query syncronously
SelectExecute a select query asyncronously
SelectSyncExecute a select query syncronously

Fechar

Closes the Database

my_database:Close()

Execute

Execute a query asyncronously

Callback will be in the format (rows_affected)

my_database:Execute(query, function(rows_affected)
-- Do Something...
end, parameters...)
TypeParameterDefault ValueDescription
stringqueryQuery to execute
functioncallbacknilCallback to call when finishes
anyparameters...nilSequence of parameters to escape into the Query

ExecuteSync

Execute a query syncronously

Returns a number of affected_rows

local affected_rows = my_database:ExecuteSync(query, parameters...)
TypeParameterDefault ValueDescription
stringqueryQuery to execute
anyparameters...nilSequence of parameters to escape into the Query

Select

Execute a select query asyncronously

Callback will be in the format (rows)

my_database:Select(query, function(rows)
-- Do something
end, parameters...)
TypeParameterDefault ValueDescription
stringqueryQuery to select
functioncallbacknilCallback to call when finishes
anyparameters...nilSequence of parameters to escape into the Query

SelectedSync

Selects a query syncronously

Returns a table of tables contains the rows fetched

local rows = my_database:SelectedSync(query, parameters...)
TypeParameterDefault ValueDescription
stringqueryQuery to select
anyparameters...nilSequence of parameters to escape into the Query

Connection String

Each Database Engine has it's own parameters which can be used on the connection_string constructor. Those parameters are defined and backend-dependent by the Engine, being passed directly to the Backend when creating the connection.

They should be set in the following format: "param1=value1 param2=value2 param3=value3".

tip

Usually you don't need to explicitly define all (or most) of the parameters described here, just use the ones you make sure are useful for your needs. Some of them are described by the libraries but aren't 100% tested in nanos world.

SQLite

tip

There is a special connection_string for SQLite: :memory:. This will create a database in the memory which is destroyed when the server closes.

ParameterDefault ValueDescription
db/dbnameThe database name
timeout0set sqlite busy timeout (in seconds) (link)
readonlyfalseopen database in read-only mode instead of the default read-write (note that the database file must already exist in this case, see the documentation)
synchronousset the pragma synchronous flag (link)
shared_cacheshould be true (link)
vfsset the SQLite VFS used to as OS interface. The VFS should be registered before opening the connection, see the documentation

MySQL

ParameterDefault ValueDescription
db/dbnameThe database name
userUser name to connect as
password/passPassword to be used if the server demands password authentication
hostName of host to connect to
PortaPort number to connect to at the server host
unix_socket
sslca
sslcert
local_infileshould be 0 or 1, 1 means MYSQL_OPT_LOCAL_INFILE will be set
charset
reconnect0if set to 1, will attempt to reconnect on connection loss
connect_timeoutshould be positive integer value that means seconds corresponding to MYSQL_OPT_CONNECT_TIMEOUT
read_timeoutshould be positive integer value that means seconds corresponding to MYSQL_OPT_READ_TIMEOUT
write_timeoutshould be positive integer value that means seconds corresponding to MYSQL_OPT_WRITE_TIMEOUT

PostgreSQL

More parameters and complete information can be found at the PostgreSQL Official Documentation.

ParameterDefault ValueDescription
hostName of host to connect to
hostaddrNumeric IP address of host to connect to
PortaPort number to connect to at the server host
usersame as OS user nameUser name to connect as
dbnamesame as user nameThe database name
SenhaPassword to be used if the server demands password authentication
connect_timeout0Maximum wait for connection, in seconds
optionsCommand-line options to be sent to the server