Sybase SQL Server(TM)Utility Programs for UNIX (Chapter 3)
This chapter introduces the interactive SQL utility isql and discusses some isql topics: changing the command terminator, the interaction of the performance option and command terminator values, setting the network packet size, and input and output files.
You can use SQL directly from the operating system with the standalone utility program isql . You must have an account, or login, on SQL Server. To access the account, enter this command at your operating system prompt:
isql
The following prompt appears:
Password:
Type your password at the prompt and press the Return key. The password does not appear on the screen as you type. The isql prompt appears, as follows:
1>
You can now start issuing Transact-SQL commands. The isql program sends the commands to SQL Server, formatting the results and printing them to standard output. There is no maximum size for an isql statement.
Terminate a command by typing the default command terminator go on a new line. For example:
isql
Password:
1> select *
2> from authors
3> where city = "Oakland"
4> go
To exit isql , type "quit" or "exit" on a line by itself.
Table 3-1 describes the command line options that change the format of isql output:
| Option | Default | Meaning |
|---|---|---|
| -h headers | 1 | Number of rows to print between column headings |
| -s colseparator | Single space | Changes the column separator character |
| -w linewidth | 80 characters | Changes the line width |
To include each command issued to isql in the output, use the -e option; use the -n option to remove numbering and prompt symbols. For example:
isql -e -n -o output
Password:
select *
from authors
where city = "Oakland"
go
quit
cat output
select *
from authors
where city = "Oakland"
au_id au_lname au_fname
phone address
city state country postalcode
----------- ------------------ --------------------------
------------ ----------------------------------------
-------------------- ----- ------------ ----------
213-46-8915 Green Marjorie
415 986-7020 309 63rd St. #411
Oakland CA USA 94618
274-80-9391 Straight Dick
415 834-2919 5420 College Av.
Oakland CA USA 94609
724-08-9931 Stringer Dirk
415 843-2991 5420 Telegraph Av.
Oakland CA USA 94609
724-80-9391 MacFeather Stearns
415 354-7128 44 Upland Hts.
Oakland CA USA 94612
756-30-7391 Karsen Livia
415 534-9219 5720 McAuley St.
Oakland CA USA 94609
(5 rows affected)
Note that the output file does not include the command terminator.
If you make an error when typing a Transact-SQL command, you can:
Table 3-2 lists the set options that affect Transact-SQL output. For more information, refer to the set command in the SQL Server Reference Manual .
| set Option | Default | Meaning |
|---|---|---|
| char_convert | Off | Turns character set conversion off and on between SQL Server and a client; it also starts a conversion between the server character set and a different client character set |
| fipsflagger | Off | Warns when any Transact-SQL extensions to entry level SQL92 are used |
| flushmessage | Off | Sends messages as they are generated |
| language | us_english | Sets the language for system messages |
| nocount | Off | Turns off report of number of rows affected |
| noexec | Off | Compiles each query but does not execute it; often used with showplan |
| parseonly | Off | Checks the syntax of queries and returns error messages without compiling or executing the queries |
| showplan | Off | Generates a description of the processing plan for a query; does not print results when used inside a stored procedure or trigger |
| statistics io statistics time | Off | Displays performance statistics after each execution |
| statistics subquerycache | Off | Displays the number of cache hits, misses, and rows in the subquery cache for each subquery |
| textsize | 32KB | Controls the number of bytes of text or image data returned |
If you include the command terminator argument ( -c ), you can choose your own terminator symbol; "go" is the default value for this option. You must always enter the command terminator without blanks or tabs in front of it.
For example, to use a period as the command terminator, invoke isql as follows:
isql -c.
A sample isql session with this command terminator looks like this:
1> select name from sysusers
2> .
name
-----------
sandy
kim
leslie
(3 rows affected)
Using the isql command terminator option with scripts requires advance planning:
isql provides a performance statistics option ( -p ). For example:
isql -p
1> select * from sysobjects
2> go
returns the following statistics:
1 xact:
Clock Time (ms.): total = 2000 avg = 2000 (0.50 xacts per sec.)
This means that a single transaction took 2,000 milliseconds, so the average is one transaction per 2,000 milliseconds. The clock time value reflects the entire transaction, which starts when Client-Library builds the query and ends when Client-Library returns the information from SQL Server.
You can gather performance statistics based on executing one or more transactions. To gather statistics on more than one transaction, specify a number after the command terminator ( go , by default). For example:
isql -p
1> select * from sysobjects
2> go 3
instructs SQL Server to execute three select * transactions and report the performance statistics. SQL Server returns:
3 xacts:
Clock Time (ms.): total = 1000 avg = 333 (3.00 xacts per sec.)
The -A size option specifies the network packet size to use for this isql session For example:
isql -A 2048
sets the packet size to 2,048 bytes for this isql session. To check, type:
select * from sysprocesses
The value appears under the network_pktsz heading.
size must be between the values of the default network packet size and max network packet size configuration parameters, one-third the size of the additional network memory configuration parameter, and must be a multiple of 512. SQL Server uses the closest available packet size that is a multiple of 512 if there is not enough memory available.
Use packet sizes larger than the defaults to perform I/O-intensive operations, such as readtext or writetext operations.
Setting or changing SQL Server's packet size does not affect the remote procedure call's packet size.
You can specify input and output files on the command line with the -i and -o options.
isql does not provide formatting options for the output. However, you can use the -n option to eliminate the isql prompts, and use other tools to reformat the output.
If you use the -e option, isql echoes the input to output. The resulting output file contains both the queries and their results.
The UNIX redirection symbols, "<" and ">", provide a similar mechanism to the -i and -o options, as follows:
isql -Usa -P password < input > output
You can direct isql to take input from the terminal, as in the following example:
isql -Usa -P password << EOF > output
select * from table
go
EOF
"<<EOF" instructs isql to take input from the terminal until the string "EOF." You can replace "EOF" with any character string.
Similarly, the following example signals the end of input with Ctrl-d:
isql -Usa -P password << > output
Please address any comments, suggestions or requests to:
rpt@jach.hawaii.edu Last modified: Fri Jan 7 12:52:57 HST 2000