What does this mean? I am attempting to go through Zed Shaw's alpha of Learn SQL The Hard Way, and I'm confused about the process of creating db and sql files, and specifically what the "<" means in this context.
Thanks for your help.
This is shell or command line syntax.
The < means "redirect standard input". It means use ex5.sql as an input file. It's an operator that your command line interpreter understands (bash on Linux, cmd.exe or Command Prompt on Windows, Terminal on OS X). -echo means print the commands executed to the screen as they're run. ex3.db is the file name of the resulting database.
The command tells sqlite to create or open a database called ex3.db, then run the SQL commands in ex5.sql with that database. Additionally, print all the commands as they're run to the screen.
You can see the full command line syntax by running sqlite3 -help.
Related
I am working on a unix machine and the only way to execute oracle sql commands is through a unix script we grant access like this :
#! /user/bin/ksh
User = 'PATH' # I can't read the file in this path
sqlplus $user << word # I don't know what it is used for
And then I start writing sql commands then execute the script through cmd
My question is:
Do I have any way to login to sqlplus directly through the info above through cmd
I tried to use this command to log in directly to SQL*Plus:
sqlplus $user << word # I don't know what it is used for
But it prompted username: # which I don't know
User = 'PATH' # I can't read the file in this path
There is no file to read. You are assigning the string literal 'PATH' to the environment variable "User". You could just as well say "User = 'FUBAR'"
sqlplus $user << word # I don't know what it is used for
It is telling the OS to launch the executable 'sqlplus', pass it the value of the environment variable "$user", then redirect other input from the next lines of the script until it comes to the string literal 'word'. This is call 'input redirection, and the commands between this line and the line beginning with the word 'word' are sometimes referred to as "a 'here' document". Using the string literal 'word' to terminate it is wierd and misleading at best. Most people use some variation of 'EOF' for this purpose.
I don't know what it is expected to be used for either. In *nix, environment variables (as are file names) are case sensitive. So this variable , "user" is not the same variable, "User" as you set in the previous line.
And then i start writing sql commands then execute the script through
cmd
I'm not sure what you mean by this. Are you saying that at this point, your script has sql commands intended to be processed by sqlplus? As indicated by your use of input redirection?
But it prompted username : # which I don't know
Well, in spite of all the other issues, if you don't know the username and password, you will never be able to connect to the database.
If your unix box is setup correctly the variable PATH should include /usr/local/bin you can test by typing in the command echo $PATH.
if its setup, the source in the oracle file oraenv like so
. oraenv
Note there should be a space between the period a the word oraenv. By doing this it should append the directories $ORACLE_HOME:$ORACLE_HOME/bin to the PATH variable. Since sqlplus is in $ORACLE_HOME/bin it should now be found.
I wouldn't recommend deviating from this standard. You should speak to your unix admin and Oracle dba to make sure this is setup correctly
I have a dynamic sql file in which name of TBCREATOR changes as given in a parameter.
I use a simple python script to change the TBCREATOR=<variable here> and write the result to an output sql file.
calling this file using db2 -td# -vf <generated sql file>gives
DSNC105I : End of file reached while reading the command
Here is the file i need the TBCREATOR variable replaced:
CONNECT to 204.90.115.200:5040/DALLASC user *** using ****#
select REMARKS from sysibm.SYSCOLUMNS WHERE TBCREATOR='table' AND NAME='LCODE'
#
Here is the python script:
#!/usr/bin/python3
# #------replace table value with schema name
# print(list_of_lines)
fin = open("decrypt.sql", "rt")
#output file to write the result to
fout = open("decryptout.sql", "wt")
for line in fin:
fout.write(line.replace('table', 'ZXP214'))
fin.close()
fout.close()
After decryptout.sql is generated I call it using db2 -td# -vf decryptout.sql
and get the error given above.
Whats irritating is I have another sql file that contains exactly same data as decryptout.sql which runs smoothly with the db2 -td# -vf ... command. I tried to use the unix command cmp to compare the generated file and the one which I wrote, with the variable ZXP214 already replaced but there are no differences. What is causing this error?.
here is the file (that executes without error) I compare generated output with:
CONNECT to 204.90.115.200:5040/DALLASC user *** using ****#
select REMARKS from sysibm.SYSCOLUMNS WHERE TBCREATOR='ZXP214' AND NAME='LCODE'
#
I found that specifically on the https://ibmzxplore.influitive.com/ challenge, if you are using the java db2 command and working in the Zowe USS system (Unix System Services of zOS), there is a conflict of character sets. I believe the system will generally create files in EBCDIC format, whereas if you do
echo "CONNECT ..." > syscat.clp
the resulting file will be tagged as ISO8859-1 and will not be processed properly by db2. Instead, go to the USS interface and choose "create file", give it a folder and a name, and it will create the file untagged. You can use
ls -T
to see the tags. Then edit the file to give it the commands you need, and db2 will interoperate with it properly. Because you are creating the file with python, you may be running into similar issues. When you open the new file, use something like
open(input_file_name, mode=”w”, encoding=”cp1047”)
This makes sure the file is open as an EBCDIC file.
If you are using the Db2-LUW CLP (command line processor) that is written in c/c++ and runs on windows/linux/unix, then your syntax for CONNECT is not valid.
Unfortunately your question is ambigiously tagged so we cannot tell which Db2-server platform you actually use.
For Db2-LUW with the c/c++ written classic db2 command, the syntax for a type-1 CONNECT statement does not allow a connection-string (or partial connection string) as shown in your question. For Db2-LUW db2 clp, the target database must be externally defined (i.e not inside the script) , either via the legacy actions of both catalog tcpip node... combined with catalog database..., or must be defined in the db2dsdriver.cfg configuration file as plain XML.
If you want to use connection-strings then you can use the clpplus tool which is available for some Db2-LUW client packages, and is present on currently supported Db2-LUW servers. This lets you use Oracle style scripting with Db2. Refer to the online documentation for details.
If you not using the c/c++ classic db2 command, and you are instead using the emulated clp written in java only available with Z/OS-USS, then you must open a ticket with IBM support for that component, as that is not a matter for stackoverflow.
Currently I'm working with Exasol database first time and came across one script which is responsible to run sql script written in .sql file.
Here is the script
C:\Program Files\EXASOL\EXASolution\EXAplus\exaplusx64.exe -configDir EXASolutionConfig -profile profile_PROD_talend -q -f D:/Data/Customer/PROD/EXASolution_SQL/EXASOL_data_script.sql -- databaseName tableName /exasolution/StageArea/fileName.csv
I want to know, how this script is working and what its doing actually ? What I understood so far is below
First "C:\Program Files\EXASOL\EXASolution\EXAplus\exaplusx64.exe " is starting a Exasol on command line and then its pointing to the script where .sql file is located.
Not getting:
1) What this part is doing "-configDir EXASolutionConfig -profile profile_PROD_talend -q -f "?
2) What are these identifiers doing "-q -f "?
3)After launching exaplusx64.exe, Is exasol going to connect with database and table name mentioned in script ? If then How cav file is paying its role in this script ? I mean in .sql there is just an sql statement, If its taking data from file then how ? I'm not getting this ..!!
Please share your comments
1) This where you say to Exasol to read the profile profile_PROD_talend in the folder EXASolutionConfig and execute the file D:/Data/Customer/PROD/EXASolution_SQL/EXASOL_data_script.sql in quiet mode (-q).
From the manual:
-configDir *This is not actually in the EXASOL manual, I assume it's the folder with the profiles, or maybe it does nothing*
-profile Name of connection profile defined in <configDir>/profiles.xml (profiles can be edited in the GUI version). You can use a profile instead of specifying all connection parameters.
-q Quiet mode which suppresses additional output from EXAplus.
-f Name of a text file containing a set of instructions that run and then stop EXAplus.
2) Quiet mode and flag for the name of the file.
3) When you run this command EXAPlus connects to the db using the information provided in the profile and it will execute the .sql file passed.
Now things become interesting, the -- allows you to pass some arguments to the .sql file. So you are passing three parameters (databaseName, tableName, and /exasolution/StageArea/fileName.csv). If you open the sql script you will find &1, &2, and &3, these are the placeholders for the parameters passed by your command.
From the manual again:
-- <args> SQL files can use arguments given over via the parameter “-- ” by evaluating the variables &1, &2 etc. .
For example, the file test.sql including the content
--test.sql
SELECT * FROM &1;
can be called in the following way:
exaplus -f test.sql -- dual
I was originally trying to run an executable (tftpd32.exe) from Expect with the following command, but for some unknown reason it would hanged the entire script:
exec c:/tftpd32.351/tftpd32.exe
So, decided to call a batch file that will start the executable.
I tried to call the batch file with the following command, but get an error message stating windows cannot find the file.
exec c:/tftpd32.351/start_tftp.bat
I also tried the following, but it does not start the executable:
spwan cmd.exe /c c:/tftpd32.351/start_tftp.bat
The batch file contains this and it run ok when I double click on it:
start tftpd32.exe
Any help would be very much appreciated.
Thanks
The right way to run that program from Tcl is to do:
set tftpd "c:/tftpd32.351/tftpd32.exe"
exec {*}[auto_execok start] "" [file nativename $tftpd]
Note that you should always have that extra empty argument when using start (due to the weird way that start works; it has an optional string in quotes that specifies the window title to create, but it tends to misinterpret the first quoted string as that even if that leaves it with no mandatory arguments) and you need to use the native system name of the executable to run, hence the file nativename.
If you've got an older version of Tcl inside your expect program (8.4 or before) you'd do this instead:
set tftpd "c:/tftpd32.351/tftpd32.exe"
eval exec [auto_execok start] [list "" [file nativename $tftpd]]
The list command in that weird eval exec construction adds some necessary quoting that you'd have trouble generating otherwise. Use it exactly as above or you'll get very strange errors. (Or upgrade to something where you don't need nearly as much code gymnastics; the {*} syntax was added for a good reason!)
It seems as if a script with #! prefix can have the interpreter name and ONLY one argument. Thus:
#!/bin/ls -l
works, but
#!/usr/bin/env ls -l
doesn't
Do you agree? Any thoughts?
Francesc
Different Unixes interpret #! differently. Here's a comprehensive-looking writeup: http://www.in-ulm.de/~mascheck/various/shebang/
It seems that the lowest common denominator across platforms is "the interpreter (which must not itself be a script) and no more than one argument".
Originally, we only had one shell on Unix. When you asked to run a command, the shell would attempt to invoke one of the exec() system calls on it. It the command was an executable, the exec would succeed and the command would run. If the exec() failed, the shell would not give up, instead it would try to interpret the command file as if it were a shell script.
Then unix got more shells and the situation became confused. Most folks would write scripts in one shell and type commands in another. And each shell had differing rules for feeding scripts to an interpreter.
This is when the “#! /” trick was invented. The idea was to let the kernel’s exec () system calls succeed with shell scripts. When the kernel tries to exec () a file, it looks at the first 4 bytes which represent an integer called a magic number. This tells the kernel if it should try to run the file or not. So “#! /” was added to magic numbers that the kernel knows and it was extended to actually be able to run shell scripts by itself. But some people could not type “#! /”, they kept leaving the space out. So the kernel was expended a bit again to allow “#!/” to work as a special 3 byte magic number.