lua对sqlite数据库操作封装

DB = {}db_e = require "luasql.sqlite3"function open_db( ... )    -- body    env = assert(db_e.sqlite3())    db =assert(env:connect("test.db"))endfunction DB.query(sql)    -- body    open_db()    local res = assert(db:execute(sql))    local tb = {}    local t = {}    local i = 1    while(nil ~= res:fetch(t, 'a')) do        tb[i] = {}        tb[i] = t        t = {}  --must    end    res:close()    close_db()    return tb    --tb每个元素都是一个tableendfunction DB.exec(sql)                                                  -- body               open_db()             assert(db:execute(sql))        close_db()            endfunction close_db( ... )    -- body    db:close()    env:close()endreturn DB