Does TABLE exist?

[azmanar]

Hi,

Does anyone know how to perform a check whether a TABLE exist or not?

The main purpose is to check whether a TABLE has been created or not. If TABLE has been created then do something. If the TABLE does not exist, do something else.

Thank you.

[ShadowUK]

Hi,

Does anyone know how to perform a check whether a TABLE exist or not?

The main purpose is to check whether a TABLE has been created or not. If TABLE has been created then do something. If the TABLE does not exist, do something else.

Thank you.

if (type(Value) == "table") then
    -- It's a table.
else 
    -- It's not a table.
end

I hope you don't mean SQLite

[RizlaUK]

i usally just try and create the table, if already exists then sqlite throws an error "(30001) table already exists"

eg

if not db then
	db =  SQLite.Open(_TempFolder .. "\\MyDatabase.db");
end

-- create a table with 3 columns
SQLite.Query(db,"create table foo(a integer primary key, b text, c integer)");

err = Application.GetLastError();
if err == SQLite.ERROR then
	if err == 30001 then
		-- table exist
	    strErrMsg = SQLite.GetLastErrorString();
	    Dialog.Message("Notice", "table already exist");
	else
		-- generic error
	    strErrMsg = SQLite.GetLastErrorString();
	    Dialog.Message("Error:"..err, strErrMsg, MB_OK, MB_ICONEXCLAMATION);
	end
else
	-- no table or error
	
end

if (type(Value) == "table") then
-- It's a table.
else
-- It's not a table.
end

if only it were that easy, lol

[azmanar]

Hi,

Sorry. What I meant was LUA Table and not SQLite Table.

So, anyone has ideas about this?

I need to search whether a Table already exist. If it does not exist, I will do something.

[ShadowUK]

Hi,

Sorry. What I meant was LUA Table and not SQLite Table.

So, anyone has ideas about this?

I need to search whether a Table already exist. If it does not exist, I will do something.

Well, I did explain in my first post. But if you mean find if a table exists from a string?

[RizlaUK]

in that case shadow had it :yes

a more generic approch

function TableDoesExist(t)
	if t and (type(t) == "table") then
		return true
	else
		return false
	end 
end

-- useage
if TableDoesExist(t) then
	-- It's a table.
else
	-- It's not a table.
end

[azmanar]

Hi,

Thanks Shadow & Rizla.

The function is exactly what I needed.

If anyone has other ideas, please share with us here.

[reteset]

if a table exist its a table even if it is empty,
if specified unknown variable is not a table it is nil
or any other type (number , string ,boolean)

[azmanar]

AMS Value Types

Hi,

Exactly, Reteset. Including function.

Shadow's function is useful to identify value types and check if it existed. There are 6 value types in AMS, i.e, Number, String, Boolean, Table, Function and Nil.

Thank you Shadow, Rizla and Reteset. Very good tips.

[ShadowUK]

Hi,

Exactly, Reteset. Including function.

Shadow's function is useful to identify value types and check if it existed. There are 6 value types in AMS, i.e, Number, String, Boolean, Table, Function and Nil.

Thank you Shadow, Rizla and Reteset. Very good tips.

You forgot userdata and thread.