I have questions about DNS: Is this a DNS LOOP?

Hi , everyone:
I've read some text about the Domain Name System, And found something I can't understand:
Many Text Say like this:
Suppose the resolver want to get the ip address of the domain: www.example.com, The DNS Query Process looks like
1. The Resolver asks one or more of the ROOT-SERVERS
2. The ROOT-SERVERS answer to the client that www.example.com is managed by the GTLD-SERVERS, and ROOT-SERVERS Gives some additional records to the Resolver about the ip address of those GTLD-SERVERS
3. Resolver asks the GTLD-SERVERS about the domain: www.example.com
4. The GTLD-SERVERS tell the Resolver to ask the IANA-SERVERS again , and again tell the Resolver about the ip address of the Name Server of IANA-SERVERS
5. Now the Resolver go on asking the IANA-SERVERS about the domain: www.example.com , NOW the IANA-SERVERS answers the Resolver about the ip address of www.example.com
My First Question is:
Does Resolver Relay on the ADDITIONAL SECTION?
Now Suppose I have two domains: example.com and example.org
And i have registered my own NameServer: ns.example.com and ns.example.org
Now I go to the registrar and change my DNS as follows:
example.com => ns.example.org
example.org => ns.example.com
Then the resolver asks the www.example.com again, In my opinion , the process my looks like this:
1. Resolver asks the ROOT-SERVERS of the domain www.example.com
2. ROOT-SERVER answers that the Resolver should ask GTLD-SERVERS, and tell it the ip addresses of those GTLD-SERVERS
3. Resolver now asks one or more of the GTLD-SERVERS ,
4. The GTLD-SERVERS answers the Resolver that he should ask ns.example.org , but the GTLD-SERVERS does not know the ip address of ns.example.org , because the ORG domain is not managed by them.
Then the Resolver must know the ip address of ns.example.org first if he want to resolve www.example.com
5. Resolver asks the ROOT-SERVERS of the domain ns.example.org
6. ROOT-SERVERS tell him to ask a0.org.afilias-nst.org. .... and give hime some additional records
7. Resolver asks a0.org.afilias-nst.org
8. a0.org.afilias-nst.org tell him to ask ns.example.com, because as HE Knows , it's the name server of example.org , But HE does not have any additional records about ns.example.com because the COM domain is managed by GTLD-SERVERS..
Then the Resolver must know the ip address of ns.example.com first if he want to resolve ns.example.org ?
9. Resolver asks the ROOT-SERVERS of the domain: ns.example.com
10. ROOT-SERVERS tell hime to ask GTLD-SERVERS
11. Resolver asks the GTLD-SERVERS about the domain: ns.example.com
12. GTLD-SERVERS tell him to ask ns.example.org..
LOOP...
I don't know if my knowledge is right. My Second Question is:
As I have register my own NameServer: ns.example.com , GTLD-SERVERS has the records of ns.example.com in it's database, But when I ask him ns.example.com , Why He tell me to ask ns.example.org ? Why not just answer me that he has the ip address of my NameServer?
Hope some one explain it clearly. Thanks

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Hi,
leave_for wrote:
HI,
I have question about dml mechanism. particularly delete statement
I learned that SQL statements deal with each row. I'm not sure what you mean.
SQL statements deal with sets of rows ; there may be 0, 1, 2, 3 or more rows in the set.
For example, SELECT statement insert each record(1 row) which matched with term of WHERE into record pool.You must mean an INSERT or MERGE statement that includes a query. A plain old SELECT statement doesn't insert anything, or change any table in any way.
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if so, Do DELETE statements deal with each row which is matched with terms WHERE statements? ortherwise with rownum?
I hope that I know the mechanism of DELETE statement?Sorry; the last couple of lines you wrote are especially confusing.
When you have a DELETE statement that includes a WHERE clause, such as
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