...a few minuts ago, i've sketched a simple framless dinning table, i'd like to share...
That is a clean looking design...Good job...!!!
I believe the more germane term to describe your design would be "skirt-less" perhaps and not "frame-less?
Traditional "skirt-less" designs are very old in orgin with most coming from the Middle East and Asia...
...are the legs should be fit simply with lag-screws or a steel plate should be embedded under the table for each leg?
When attempts are made today create the "sleek looking" designs that many enjoy today...to many corners are cut to "dumb down" the design and ignore how a design evolved over millenia. "Skirt-less Tables" are not a design to be trifled with or to cut corners on...not unless one has a great deal of experience in advanced woodworking and joinery methods.
"Hardware" is a corner cutting approach that can get these types of tables built...but most do not fare well
in applied use as a table for very long whether in ...big or small...versions of them. The leg assemblies often rapidly tends to loosen with as the metal can not take the cyclic actions of use. Those that do present as more robust often have metal legs and/or invisible metal frame work within and/or inside the wood top itself, however, this moves away (rapidly) from woodworking and more into metal craft.
In the traditional versions of these the "skirt-less tables" the legs are joined directly (in most examples) to the wood diaphragm assembly that forms the top of the table itself...or...some create an illusion (for lack of a better description) of being "skirt-less." A primary group is: 龙凤榫加穿带 (Lóngfèng sǔn jiā chuān dài - "Dragon and Phoenix" joinery systems and related.)
The many names and methods are to numerous to list in just a post like this as the topic can (and has) filled books and scrolls both. I will share a few simple examples of the more common joinery systems employed that fall in this family of systems. One of the most wonderful, robust and award winning examples of this family of joint was taken by an designers Kunt and Marianna Hagberg working with "Ikea." It is probably today the best example in mass production (and good service) of a "skirt-less" table design!!!
Here are some additional "modern" design applications of traditional joinery for building "skirt-less" tables.