WHAT IS A BATCH v7.0?
A batch is a set of commands sent to SQL Server as one unit of work. 
The following will outline what happens when SQL Server receives a 
batch. The batch separator is the GO keyword. The examples below should 
assist in this concept. Assume the following table structure.

CREATE TABLE TableX (Col1 INT NOT NULL).

Batch #1
INSERT INTO TableX (Col1) VALUES (1) 
INSERT INTO TableX (Col1) VALUES (2) 
GO

Batch #2
INSERT INTO TableX (Col1) VALUES (3) 
INSERT INTO TableX (Col1) VALU (4) 
GO

Batch #3
INSERT INTO TableX (Col1) VALUES (NULL) 
INSERT INTO TableX (Col1) VALUES (5) 
GO

Upon submitting a batch to SQL, the server takes it as a string of T-
SQL commands and parses the string for syntax. If no syntax error(s) 
are found, as in Batch #1, then all of the statement(s) are executed. 
If a syntax error is found, as in Batch #2, then none of the statements 
are executed and SQL Server returns an error to the client.

Note that Batch #3 is syntactically correct but will violate the NOT 
NULL constraint. This is still considered a syntax-valid batch so, even 
though the INSERT NULL command will fail, the second command is valid 
and will be executed/inserted into the table. Values 1, 2, and 5 will 
be inserted. Note that this behavior applies for constraint violations. 
Some run-time errors stop the current statement as well as subsequent 
statements within the batch.

The following rules for batches are reprinted from MSDN Books Online:

1. CREATE DEFAULT, CREATE PROCEDURE, CREATE RULE, CREATE TRIGGER, and 
CREATE VIEW statements cannot be combined with other statements in a 
batch.
2. A table cannot be altered and then the new columns referenced in the 
same batch.
3. If an EXECUTE statement is the first statement in a batch, the 
EXECUTE keyword is not required. The EXECUTE keyword is required if the 
EXECUTE statement is not the first statement in the batch.

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