SQL appender
The SQL appender can be used to write log messages to a SQL database table. It uses LuaSQL, therefore any database supported by LuaSQL can be used.
function logging.sql{
    connectionfactory = function,
    [tablename = string,]
    [logdatefield = string,]
    [loglevelfield = string,]
    [logmessagefield = string,]
    [keepalive = boolean],
}
- connectionfactory:
 This must be a function that creates a LuaSQL connection object. This function will be called everytime a connection needs to be created.
- tablename:
 The name of the table to write the log requests. Default value is- "LogTable".
- logdatefield:
 The name of the field to write the date of each log request. Default value is- "LogDate".
- loglevelfield:
 The name of the field to write the level of each log request. Default value is- "LogLevel".
- logmessagefield:
 The name of the field to write the message of each log request. Default value is- "LogMessage".
- keepalive:
 In every log request a connection to the database is opened, the message is written, and the connection is closed.
 If the user wants to keep the connection opened he can specify- keepalive = true.
Example
require"logging.sql"
require"luasql.jdbc"
local env, err = luasql.jdbc('com.mysql.jdbc.Driver')
local logger = logging.sql {
  connectionfactory = function()
    local con, err = env:connect('jdbc:mysql://localhost/test',
                                 'tcp', '123')
    assert(con, err)
    return con
  end,
  keepalive = true,
}
logger:info("logging.sql test")
logger:debug("debugging...")
logger:error("error!")
