Why does the BEGIN/END commands in this script change the function of the script to loop over all records before doing the division by the norm?
Statements in BEGIN block will be executed before reading any line of file and statements in END block will be executed after all the lines in file are read.
So, initially 's' is set to 0. And $1^2 + $2^2 + $3^2 of each line is added to 's' iteratively. After all the lines are read, sqrt(s) is printed.
Another C++ question, please do notify me if this forum is C-only!
:)
I'm having a vector...
vector<Person> x;
... with a class I've defined (Person).
I have several elements in this vector and I would like to save it to a file (binary (?)). And later on open up this file to retrieve... (1 Reply)
using SUN C++ I have a problem when I do a push_back on a vector. The linker gives me a undefined symbol error on __cxa_end_catch.
Any ideas, is there a library to include?
Thanks
Chris (1 Reply)
Hi
i have the following structure
struct S
{
char Mod_num;
char val;
char chr_nm_cd;
}
I am reading a 2GB file and inserting into the structure and writing into a vector.
I feel like only vector will be a right option. I tried with multimap but it is memory intensive and hence i... (1 Reply)
Hi! I need to make dynamic multidimensional arrays using the vector class. I found in this page How to dynamically create a two dimensional array? - Microsoft: Visual C++ FAQ - Tek-Tips the way to do it in 2D, and now i'm trying to expand it to 3D but i don't understand how is the operator working,... (0 Replies)
Hi! I need to make dynamic multidimensional arrays using the vector class. I found in this page How to dynamically create a two dimensional array? - Microsoft: Visual C++ FAQ - Tek-Tips the way to do it in 2D, and now i'm trying to expand it to 3D but i don't understand how is the operator working,... (1 Reply)
I modified some code I found on Wikipedia concerning maps to see if it would work before applying it to a project I'm working on that has a similar idea.
What I would want is for a user to be able to enter sentences and then be able to distinguish how many times a the person entered a word in a... (4 Replies)
Hi all,
I have a vector,the type of the element within it is list<int>,and i wanna sort this vector.So i implemented a function as a predicate for sort(the STL algorithm).Problem came when i missed the bold part in my code,g++ generated lots of error messages.And after i added the bold... (4 Replies)
Hi all, from my understanding I understand that I can use array in this manner.
struct test
{
int a;
int b;
int c;
};
test testing; //creating an array with the structer type
testing.a=1;
testing.b=2;
testing.c=3;
If I'm not wrong we can use array in this manner,... (12 Replies)
hello guys.
i'm new to c++. i've problem using two dimensional vector.
i've a project of making conway's game of life. this is the code that i have made so far.
my problem is how can i give a two dimensional vector through main.
glider.vec1 = vec; is not correct way to give a two... (2 Replies)
Is there a function to convert number (unsigned int for this example) to binary? I could not find a simple one thru google.
While I was learning bloom filter with the example, I was wondering if anybody can help me to
1) display the real bits vector for the bloomfilter;
2) if dataset is very... (11 Replies)
Discussion started by: yifangt
11 Replies
LEARN ABOUT SUSE
begin
BEGIN(7) SQL Commands BEGIN(7)NAME
BEGIN - start a transaction block
SYNOPSIS
BEGIN [ WORK | TRANSACTION ] [ transaction_mode [, ...] ]
where transaction_mode is one of:
ISOLATION LEVEL { SERIALIZABLE | REPEATABLE READ | READ COMMITTED | READ UNCOMMITTED }
READ WRITE | READ ONLY
DESCRIPTION
BEGIN initiates a transaction block, that is, all statements after a BEGIN command will be executed in a single transaction until an
explicit COMMIT [commit(7)] or ROLLBACK [rollback(7)] is given. By default (without BEGIN), PostgreSQL executes transactions in ``autocom-
mit'' mode, that is, each statement is executed in its own transaction and a commit is implicitly performed at the end of the statement (if
execution was successful, otherwise a rollback is done).
Statements are executed more quickly in a transaction block, because transaction start/commit requires significant CPU and disk activity.
Execution of multiple statements inside a transaction is also useful to ensure consistency when making several related changes: other ses-
sions will be unable to see the intermediate states wherein not all the related updates have been done.
If the isolation level or read/write mode is specified, the new transaction has those characteristics, as if SET TRANSACTION [set_transac-
tion(7)] was executed.
PARAMETERS
WORK
TRANSACTION
Optional key words. They have no effect.
Refer to SET TRANSACTION [set_transaction(7)] for information on the meaning of the other parameters to this statement.
NOTES
START TRANSACTION [start_transaction(7)] has the same functionality as BEGIN.
Use COMMIT [commit(7)] or ROLLBACK [rollback(7)] to terminate a transaction block.
Issuing BEGIN when already inside a transaction block will provoke a warning message. The state of the transaction is not affected. To
nest transactions within a transaction block, use savepoints (see SAVEPOINT [savepoint(7)]).
For reasons of backwards compatibility, the commas between successive transaction_modes can be omitted.
EXAMPLES
To begin a transaction block:
BEGIN;
COMPATIBILITY
BEGIN is a PostgreSQL language extension. It is equivalent to the SQL-standard command START TRANSACTION [start_transaction(7)], whose ref-
erence page contains additional compatibility information.
Incidentally, the BEGIN key word is used for a different purpose in embedded SQL. You are advised to be careful about the transaction
semantics when porting database applications.
SEE ALSO
COMMIT [commit(7)], ROLLBACK [rollback(7)], START TRANSACTION [start_transaction(7)], SAVEPOINT [savepoint(7)]
SQL - Language Statements 2010-05-14 BEGIN(7)