sybperl - Sybase extensions to Perl
use Sybase::DBlib; use Sybase::CTlib; use Sybase::Sybperl;
Sybperl implements three Sybase extension modules to perl (version 5.002 or higher). Sybase::DBlib adds a subset of the Sybase DB-Library API. Sybase::CTlib adds a subset of the Sybase CT-Library (aka the Client Library) API. Sybase::Sybperl is a backwards compatibility module (implemented on top of Sybase::DBlib) to enable scripts written for sybperl 1.0xx to run with Perl 5. Using both the Sybase::Sybperl and Sybase::DBlib modules explicitly in a single script is not garanteed to work correctly.
The general usage format for both Sybase::DBlib and Sybase::CTlib is this:
use Sybase::DBlib; # Allocate a new connection, usually refered to as a database handle $dbh = new Sybase::DBlib username, password; # Set an attribute for this dbh: $dbh->{UseDateTime} = TRUE; # Call a method with this dbh: $dbh->dbcmd(sql code);
The DBPROCESS or CS_CONNECTION that is opened with the call to new() is automatically closed when the $dbh goes out of scope:
sub run_a_query { my $dbh = new Sybase::CTlib $user, $passwd; my @dat = $dbh->ct_sql("select * from sysusers"); return @dat; } # The $dbh is automatically closed when we exit the subroutine.
The Sybase::DBlib and Sybase::CTlib modules make a use of attributes that are either package global or associated with a specific $dbh. These attributes control certain behavior aspects, and are also used to store status information.
Package global attributes can be set using the %Att hash table in either modules. The %Att variable is not exported, so it must be fully qualified:
$Sybase::DBlib::Att{UseDateTime} = TRUE;
NOTE: setting an attribute via the %Att variable does NOT change the status of currently allocated database handles.
In this version, the available attributes for a $dbh are set when the $dbh is created. You can't add arbitrary attributes during the life of the $dbh. This has been done to implement a stricter behavior and to catch attribute errors.
It is possible to add your own attributes to a $dbh at creation time. The Sybase::BCP module adds two attributes to the normal Sybase::DBlib attribute set by passing an additional attribute variable to the Sybase::DBlib new() call:
$d = new Sybase::DBlib $user,$passwd, $server,$appname, {Global => {}, Cols => {}};
As of version 2.04, the Sybase DATETIME and MONEY datatypes can be kept in their native formats in both the Sybase::DBlib and Sybase::CTlib modules. In addition, NUMERIC or DECIMAL values can also be kept in their native formats when using the Sybase::CTlib module. This behavior is normally turned off by default, because there is a performance penalty associated with it. It is turned on by using package or database handle specific attributes.
Please see the discussion on Special handling of DATETIME, MONEY & NUMERIC/DECIMAL values below for details.
In general, I have tried to make the calls in this package behave the same way as their C language equivalents. In certain cases the parameters are different, and certain calls (dblogin() for example) don't do the same thing in C as in Perl. This has been done to make the life of the Perl programmer easier.
You should if possible have the Sybase Open Client documentation available when writing Sybperl programs.
A generic perl script using Sybase::DBlib would look like this:
use Sybase::DBlib; $dbh = new Sybase::DBlib 'sa', $pwd, $server, 'test_app'; $dbh->dbcmd("select * from sysprocesses\n"); $dbh->dbsqlexec; $dbh->dbresults; while(@data = $dbh->dbnextrow) { .... do something with @data .... }
The API calls that have been implemented use the same calling sequence as their C equivalents, with a couple of exceptions, detailed below.
Please see also Common Sybase::DBlib and Sybase::CTlib routines below.
List of API calls
Standard Routines:
Initiates a connection to a Sybase dataserver, using the supplied user, password, server and application name information. Uses the default values (see DBSETLUSER(), DBSETLPWD(), etc. in the Sybase DB-library documentation) if the parameters are ommitted.
Both forms of the call are identical.
This call can be used multiple times if connecting to multiple servers with different username/password combinations is required, for example.
The additional attributes parameter allows you to define application specific attributes that you wish to associate with the $dbh.
Open an additional connection, using the current LOGINREC information.
Executes "use database $database" for the connection $dbh.
Appends the string $sql_cmd to the current command buffer of this connection.
Sends the content of the current command buffer to the dataserver for execution. See the DB-library documentation for a discussion of return values.
Retrieves result information from the dataserver after having executed dbsqlexec().
Send the command batch to the server, but do not wait for the server to return any results. Should be followed by calls to dbpoll() and dbsqlok(). See the Sybase docs for further details.
Wait for results from the server and verify the correctness of the instructions the server is responding to. Mainly for use with dbmoretext() in Sybase::DBlib. See also the Sybase documentation for details.
Poll the server to see if any connection has results pending. Used in conjunction with dbsqlsend() and dbsqlok() to perform asynchronous queries. dbpoll() will wait up to $millisecs milliseconds and poll any open DBPROCESS for results. If it finds a DBPROCESS that is ready it returns it, along with the reason why it's ready. If dbpoll() times out, or if an interupt occurs $dbproc will be undefined, and $reason will be either DBTIMEOUT or DBINTERUPT. If $millisecs is 0 then dbpoll() returns immediately. If $millisecs is -1 then it will not return until either results are pending or a system interupt has occured. Please see the Sybase documentation for further details.
Here is an example of using dbsqlsend(), dbpoll() and dbsqlok():
$dbh->dbcmd("exec big_hairy_query_proc"); $dbh->dbsqlsend; # here you can go do something else... # now - find out if some results are waiting ($dbh2, $reason) = Sybase::DBlib::dbpoll(100); if($dbh2) { # yes! - there's data on the pipe $dbh2->dbsqlok; while($dbh2->dbresults != NO_MORE_RESULTS) { while(@dat = $dbh2->dbnextrow) { .... } } }
Cancels the current command batch.
Cancels the current query within the currently executing command batch.
Free the command buffer (required only in special cases - if you don't know what this is you probably don't need it :-)
Force the closing of a connection. Note that connections are automatically closed when the $dbh goes out of scope.
Returns TRUE if the DBPROCESS has been marked DEAD by DBlibrary.
Returns the number of the currently executing command in the command batch. The first command is number 1.
Returns TRUE if there are additional commands to be executed in the current command batch.
Returns SUCCEED if the current command can return rows.
Returns SUCCEED if the current command did return rows
Returns the number of rows that the current command affected.
Returns the number (counting from 1) of the currently retrieved row in the current result set.
Returns the SPID (server process ID) of the current connection to the Sybase server.
Did the last executed stored procedure return a status value? dbhasretstats must only be called after dbresults returns NO_MORE_RESULTS, ie after all the selet, insert, update operations of he sored procedure have been processed.
Retrieve the return status of a stored procedure. As with dbhasretstat, call this function after all the result sets of the stored procedure have been processed.
How many columns are in the current result set.
What is the column type of column $colid in the current result set.
What is the length (in bytes) of column $colid in the current result set.
What is the name of column $colid in the current result set.
Retrieve one row. dbnextrow() returns an array of scalars, one for each column value. If $doAssoc is non-0, then dbnextrow() returns a hash (aka associative array) with column name/value pairs. This relieves the programmer from having to call dbbind() or dbdata().
If $wantRef is non-0, then dbnextrow() returns a reference to a hash or an array. This reference points to a static array (or hash) so if you wish to store the returned rows in an array, you must copy the array/hash:
while($d = $dbh->dbnextrow(0, 1)) { push(@rows, [@$d]); }
The return value of the C version of dbnextrow() can be accessed via the Perl DBPROCESS attribute field, as in:
@arr = $dbh->dbnextrow; # read results if($dbh->{DBstatus} != REG_ROW) { take some appropriate action... }
When the results row is a COMPUTE row, the ComputeID field of the DBPROCESS is set:
@arr = $dbh->dbnextrow; # read results if($dbh->{ComputeID} != 0) { # it's a 'compute by' row take some appropriate action... }
dbnextrow() can also return a hash keyed on the column name:
$dbh->dbcmd("select Name=name, Id = id from test_table"); $dbh->dbsqlexec; $dbh->dbresults; while(%arr = $dbh->dbnextrow(1)) { print "$arr{Name} : $arr{Id}\n"; }
Retrieve the value of the parameters marked as 'OUTPUT' in a stored procedure. If $doAssoc is non-0, then retrieve the data as an associative array with parameter name/value pairs.
Retrieve the contents of the command buffer.
Sets option $opt with optional character parameter $c_val and optional integer parameter $i_val. $opt is one of the option values defined in the Sybase DBlibrary manual (f.eg. DBSHOWPLAN, DBTEXTSIZE). For example, to set SHOWPLAN on, you would use
$dbh->dbsetopt(DBSHOWPLAN);
See also dbclropt() and dbisopt() below.
Clears the option $opt, previously set using dbsetopt().
Returns TRUE if the option $opt is set.
Convert $string to a 'safer' version by inserting single or double quotes where appropriate, so that it can be passed to the dataserver without syntax errors.
The second argument to dbsafestr() (normally DBSINGLE, DBDOUBLE or DBBOTH) has been replaced with a literal ' or " (meaning DBSINGLE or DBDOUBLE, respectively). Omitting this argument means DBBOTH.
Returns the TDS packet size currently in use for this $dbh.
Insert or update data in a TEXT or IMAGE column. The usage is a bit different from that of the C version:
The calling sequence is a little different from the C version, and logging is off by default:
$dbh_2 and $colnum are the DBPROCESS and column number of a currently active query. Example:
$dbh_2->dbcmd('select the_text, t_index from text_table where t_index = 5'); $dbh_2->dbsqlexec; $dbh_2->dbresults; @data = $dbh_2->dbnextrow; $d->dbwritetext ("text_table.the_text", $dbh_2, 1, "This is text which was added with Sybperl", TRUE);
Prepare to insert or update text with dbmoretext().
$dbh_2->dbcmd('select the_text, t_index from text_table where t_index = 5'); $dbh_2->dbsqlexec; $dbh_2->dbresults; @data = $dbh_2->dbnextrow; $size = length($data1) + length($data2); $d->dbpreptext ("text_table.the_text", $dbh_2, 1, $size, TRUE); $dbh->dbsqlok; $dbh->dbresults; $dbh->dbmoretext(length($data1), $data1); $dbh->dbmoretext(length($data2), $data2); $dbh->dbsqlok; $dbh->dbresults;
Sends a chunk of TEXT/IMAGE data to the server. See the example above.
Read a TEXT/IMAGE data item in $size chunks.
Example:
$dbh->dbcmd("select data from text_test where id=1"); $dbh->dbsqlexec; while($dbh->dbresults != NO_MORE_RESULTS) { my $bytes; my $buf = ''; while(($bytes = $dbh->dbreadtext($buf, 512)) != NO_MORE_ROWS) { if($bytes == -1) { die "Error!"; } elsif ($bytes == 0) { print "End of row\n"; } else { print "$buf"; } } }
See also the Sybase::BCP module.
This is an exported routine (ie it can be called without a $dbh handle) which sets the BCP IN flag to TRUE/FALSE.
It is necessary to call BCP_SETL(TRUE) before opening the connection with which one wants to run a BCP IN operation.
Retrieve the current BCP flag status.
Initialize BCP library. $direction can be DB_OUT or DB_IN
This is a utility function that does not exist in the normal BCP API. It's use is to initialize some internal variables before starting a BCP operation from program variables into a table. This call avoids setting up translation information for each of the columns of the table being updated, obviating the use of the bcp_colfmt call.
See EXAMPLES, below.
Sends the data in LIST to the server. The LIST is assumed to contain one element for each column being updated. To send a NULL value set the appropriate element to the Perl undef value.
In the second form you pass an array reference instead of passing the LIST, which makes processing a little bit faster on wide tables.
Commit rows to the database. You usually use it like this:
while(<IN>) { chop; @data = split(/\|/); $d->bcp_sendrow(\@data); # Pass the array reference # Commit data every 100 rows. if((++$count % 100) == 0) { $d->bcp_batch; } }
If you have DBlibrary for System 10 or higher, then you can pass the additional $precision and $scale parameters, and have sybperl call bcp_colfmt_ps() instead of bcp_colfmt().
Please see the DB-library documentation for these calls.
DBMONEY Routines:
NOTE: In this version it is possible to avoid calling the routines below and still get DBMONEY calculations done with the correct precision. See the Sybase::DBlib::Money discussion below.
All of these routines correspond to their DB-library counterpart, with the following exception:
The routines which in the C version take pointers to arguments (in order to return values) return these values in an array instead:
status = dbmnyadd(dbproc, m1, m2, &result) becomes ($status, $result) = $dbproc->dbmnyadd($m1, $m2)
RPC Routines:
NOTE: Check out eg/rpc-example.pl for an example on how to use these calls.
Initialize an RPC call to the remote procedure $rpcname. See the DB-library manual for valid values for $option.
Add a parameter to an RPC call initiated with dbrpcinit(). Please see the DB-library manual page for details & values for the parameters.
NOTE: All floating point types (MONEY, FLOAT, REAL, DECIMAL, etc.) are converted to FLOAT before being sent to the RPC.
Execute an RPC initiated with dbrpcinit().
NOTE: This call executes both dbrpcsend() and dbsqlok(). You can call $dbh->dbresults direcly after calling $dbh->dbrpcsend.
Set the password for connecting to a remote server.
Clear all remote server passwords.
Registered procedure execution:
These routines are used to execute an OpenServer registered procedure. Please the Sybase DBlibrary manual for a description of what these routnines do, and how to call them.
Two Phase Commit Routines:
Please see the Sybase documentation for this.
NOTE: These routines have not been thouroughly tested!
Exported Routines:
Register an error (or message) handler for DB-library to use. Handler examples can be found in sybutil.pl in the Sybperl distribution. Returns a reference to the previously defined handler (or undef if none were defined). Passing undef as the argument clears the handler.
Set the name of the 'interfaces' file. This file is normally found by DB-library in the directory pointed to by the $SYBASE environment variable.
Start recording all SQL sent to the server in file $filename.
Returns a string identifying the version of DBlibrary that this copy of Sybperl was built with.
These utility routines are probably very seldom used. See the DB-library manual for an explanation of their use.
Tell DB-library that we're done. Once this call has been made, no further activity requiring DB-library can be performed in the current program.
Utility Routines:
These routines are not part of the DB-library API, but have been added because they can make our life as programers easier, and exploit certain strenghts of Perl.
Runs the sql command and returns the result as a reference to an array of the rows. In a LIST context, return the array itself (instead of a reference to the array). Each row is a reference to an array of scalars.
If you provide a second parameter it is taken as a procedure to call for each row. The callback is called with the values of the row as parameters.
If you provide a third parameter, this is used in the call to dbnextrow() to retrieve associative arrays rather than 'normal' arrays for each row, and store them in the returned array. To pass the third parameter without passing the &rowcallback value you should pass the special value undef as second parameter:
@rows = $dbh->sql("select * from sysusers", undef, TRUE); foreach $row_ref (@rows) { if($$row_ref{'uid'} == 10) { .... } }
See also eg/sql.pl for an example.
Contributed by Gisle Aas.
NOTE: This routine loads all the data into memory. It should not be run with a query that returns a large number of rows. To avoid the risk of overflowing memory, you can limit the number of rows that the query returns by setting the 'MaxRows' field of the $dbh attribute field:
$dbh->{'MaxRows'} = 100;
This value is not set by default.
An enhanced version of the sql routine, nsql, is also available. The arguments are an SQL command to be executed, and the $type of the data to be returned. The array returned by nsql is one of the following:
Array of Hash References (if type eq HASH) Array of Array References (if type eq ARRAY) Simple Array (if type eq ARRAY, and a single column is queried Boolean True/False value (if type ne ARRAY or HASH)
Optionally, instead of the words "HASH" or "ARRAY" a reference of the same type can be passed as well. This is, both of the following are equivalent:
$dbh->nsql("select col1,col2 from table","HASH"); $dbh->nsql("select col1,col2 from table",{});
For example, the following code will return an array of hash references:
@ret = $dbh->nsql("select col1,col2 from table","HASH"); foreach $ret ( @ret ) { print "col1 = ", $ret->{'col1'}, ", col2 = ", $ret->{'col2'}, "\n"; }
The following code will return an array of array references:
@ret = $dbh->nsql("select col1,col2 from table","ARRAY"); foreach $ret ( @ret ) { print "col1 = ", $ret->[0], ", col2 = ", $ret->[1], "\n"; }
The following code will return a simple array, since the select statement queries for only one column in the table:
@ret = $dbh->nsql("select col1 from table","ARRAY"); foreach $ret ( @ret ) { print "col1 = $ret\n"; }
Success of failure of an nsql() call cannot necessarily be judged based on the value of the return code, as an empty array may be a perfectly valid result for certain sql code.
The nsql() routine will maintain the success or failure state in a variable $DB_ERROR, accessed by the method of the same name, and a pair of Sybase message/error handler routines are also provided which will use $DB_ERROR for the Sybase messages and errors as well. However, these must be installed by the client application:
dbmsghandle("Sybase::DBlib::nsql_message_handler"); dberrhandle("Sybase::DBlib::nsql_error_handler");
Success of failure of an nsql() call cannot necessarily be judged based on the value of the return code, as an emtpy array may be a perfectly valid result for certain sql code.
The following code is the proper method for handling errors with use of nsql.
@ret = $dbh->nsql("select stuff from table where stuff = 'nothing'","ARRAY"); if ( $dbh->DB_ERROR() ) { # error handling code goes here, perhaps: die "Unable to get stuff from table:" . $dbh->DB_ERROR() . "\n"; }
For compatibility with older release, the error variable $DB_ERROR is still exported, however, direct use of this variable makes it difficult to pass the Sybase::DBlib object around and use the nsql() method for queries, since the subroutine using the object will not necessarily have $DB_ERROR in its namespace. The method will always be available.
NOTE: This routine was contributed by W. Phillip Moore <wpm@ms.com>.
Constants:
Most of the #defines from sybdb.h can be accessed as Sybase::DBlib::NAME (eg Sybase::DBlib::STDEXIT) Additional constants are:
The Sybperl version. Can be interpreted as a string or as a number.
The version of DBlibrary that sybperl was built against.
The behaviour of certain aspects of the Sybase::CTlib module can be controled via global or connection specific attributes. The global attributes are stored in the %Sybase::DBlib::Att variable, and the connection specific attributes are stored in the $dbh. To set a global attribute, you would code
$Sybase::CTlib::Att{'AttributeName'} = value;
and to set a connection specific attribute you would code
$dbh->{"AttributeName'} = value;
NOTE!!! Global attribute setting changes do not affect existing connections, and changing an attribute inside a ct_fetch() does not change the behaviour of the data retrieval during that ct_fetch() loop.
The following attributes are currently defined:
If set, NULL results are returned as the Perl 'undef' value, otherwise as the string "NULL". Default: set.
If set, numeric results are not converted to strings before returning the data to Perl. Default: set.
If set, BINARY results are preceeded by '0x' in the result. Default: unset.
Turn the special handling of DATETIME values on. Default: unset. See the section on special datatype handling below.
Turn the special handling of MONEY values on. Default: unset. See the section on special datatype handling below.
These status variables are set by Sybase::DBlib internal routines, and can be accessed using the $dbh->{'variable'} syntax.
The return status of the last call to dbnextrow.
The compute id of the current returned row. Is 0 if no compute by clause is currently being processed.
See also Sybase::BCP for a symplified bulk copy API.
&BCP_SETL(TRUE); $dbh = new Sybase::DBlib $User, $Password; $dbh->bcp_init("test.dbo.t2", '', '', DB_IN); $dbh->bcp_meminit(3); # we wish to copy three columns into # the 't2' table while(<>) { chop; @dat = split(' ', $_); $dbh->bcp_sendrow(@dat); } $ret = $dbh->bcp_done;
$dbh = new Sybase::DBlib; $ret = $dbh->sql("select * from sysprocesses"); foreach (@$ret) # Loop through each row { @row = @$_; # do something with the data row... } $ret = $dbh->sql("select * from sysusers", sub { print "@_"; }); # This will select all the info from sysusers, and print it
You can get SHOWPLAN and STATISTICS information when you run a sybperl script. To do so, you must first turn on the respective options, using dbsetopt(), and then you need a special message handler that will filter the SHOWPLAN and/or STATISTICS messages sent from the server.
The following message handler differentiates the SHOWPLAN or STATICSTICS messages from other messages:
# Message number 3612-3615 are statistics time / statistics io # message. Showplan messages are numbered 6201-6225. # (I hope I haven't forgotten any...) @sh_msgs = (3612 .. 3615, 6201 .. 6225); @showplan_msg{@sh_msgs} = (1) x scalar(@sh_msgs); sub showplan_handler { my ($db, $message, $state, $severity, $text, $server, $procedure, $line) = @_; # Don't display 'informational' messages: if ($severity > 10) { print STDERR ("Sybase message ", $message, ", Severity ", $severity, ", state ", $state); print STDERR ("\nServer `", $server, "'") if defined ($server); print STDERR ("\nProcedure `", $procedure, "'") if defined ($procedure); print STDERR ("\nLine ", $line) if defined ($line); print STDERR ("\n ", $text, "\n\n"); } elsif($showplan_msg{$message}) { # This is a HOWPLAN or STATISTICS message, so print it out: print STDERR ($text, "\n"); } elsif ($message == 0) { print STDERR ($text, "\n"); } 0; }
This could then be used like this:
use Sybase::DBlib; dbmsghandle(\&showplan_handler); $dbh = new Sybase::DBlib 'mpeppler', $password, 'TROLL'; $dbh->dbsetopt(DBSHOWPLAN); $dbh->dbsetopt(DBSTAT, "IO"); $dbh->dbsetopt(DBSTAT, "TIME"); $dbh->dbcmd("select * from xrate where date = '951001'"); $dbh->dbsqlexec; while($dbh->dbresults != NO_MORE_RESULTS) { while(@dat = $dbh->dbnextrow) { print "@dat\n"; } }
Et voila!
The 2PC calls have not been well tested.
The Sybase::Sybperl package is designed for backwards compatibility with sybperl 1.0xx (for Perl 4.x). It's main purpose is to allow sybperl 1.0xx scripts to work unchanged with Perl 5 & sybperl 2. Using this API for new scripts is not recomended, unless portability with older versions of sybperl is essential.
The sybperl 1.0xx man page is included in this package in pod/sybperl-1.0xx.man
Sybase::Sybperl is layered on top of the Sybase::DBlib package, and could therefore suffer a small performance penalty.
The CT-library module has been written in colaboration with Sybase.
Establishes a connection to the database engine. Initializes and allocates resources for the connection, and registers the user name, password, target server and application name.
The attributes hash reference can be used to add private attributes to the connection handle that you can later use, and can also be used to set certain connection properties.
To set the connection properties you pass a special hash in the attributes parameter:
$dbh = new Sybase::CTlib 'user', 'pwd', 'SYBASE', undef, { CON_PROPS => { CS_HOSTNAME => 'kiruna', CS_PACKETSIZE => 1024, CS_SEC_CHALLENGE => CS_TRUE } };
The following connection properties are currently recognized:
See the Sybase documentation on how and when to use these connection properties.
Send the SQL commands $sql to the server. Multiple commands are allowed. However, you must call ct_results() until it returns CS_END_RESULTS or CS_FAIL, or call ct_cancel() before submitting a new set of SQL commands to the server.
Return values: CS_SUCCEED, CS_FAIL or CS_CANCELED (the operation was canceled).
NOTE: ct_execute() is equivalent to calling ct_command() followed by ct_send().
Append a command to the current SQL command buffer. Please check the OpenClient documentation for exact usage.
NOTE: You should only need to call ct_command()/ct_send() directly if you want to do RPCs or cursor operations. For straight queries you should use ct_execute() or ct_sql() instead.
Send the current command buffer to the server for execution.
NOTE: You only need to call ct_send() directly if you've used ct_command() to set up your SQL query.
This routine returns a results type to indicate the status of returned data. "Command Done:" result type is returned if one result set has been processed. "Row result" token is returned if regular rows are returned. This output is stored in $res_type.
The commonly used values for $res_type are CS_ROW_RESULT, CS_CMD_DONE, CS_CMD_SUCCEED, CS_COMPUTE_RESULT, CS_CMD_FAIL. The full list of values is on page 3-203 OpenClient reference manual.
See also the description of ct_fetchable() below.
The $status value takes the following values: CS_SUCCEED, CS_END_RESULTS, CS_FAIL, CS_CANCELED.
Retrieve the column names of the current query. If the current query is not a select statement, then an empty array is returned.
Retrieve the column types of the currently executing query. If $doAssoc is non-0, then a hash (aka associative array) is returned with column names/column type pairs.
Retrieves the description of each of the output columns of the current result set. Each element of the returned array is a reference to a hash that describes the column. The following fields are set: NAME, TYPE, MAXLENGTH, SCALE, PRECISION, STATUS.
You could use it like this:
$dbh->ct_execute("select name, uid from sysusers"); while(($rc = $dbh->ct_results($restype)) == CS_SUCCEED) { next unless $dbh->ct_fetchable($restype); @desc = $dbh->ct_describe; print "$desc[0]->{NAME}\n"; # prints 'name' print "$desc[0]->{MAXLENGTH}\n"; # prints 30 .... }
The STATUS field is a bitmask which can be tested for the following values: CS_CANBENULL, CS_HIDDEN, CS_IDENTITY, CS_KEY, CS_VERSION_KEY, CS_TIMESTAMP and CS_UPDATEABLE. See table 3-46 of the Open Client Client Library Reference Manual for a description of each of these values.
Retrieve one row of data. If $doAssoc is non-0, a hash is returned with column name/value pairs.
If $wantRef is non-0, then a reference to an array (or hash) is returned. This reference points to a static array (or hash), so to store the returned rows in an array you must copy the array (or hash):
while($d = $dbh->ct_fetch(1, 1)) { push(@rows, {%$d}); }
An empty array is returned if there is no data to fetch.
Issue an attention signal to the server about the current transaction. If $type == CS_CANCEL_ALL, then cancels the current command immediately. If $type == CS_CANCEL_ATTN, then discard all results when next time the application reads from the server.
Install a callback routine. Valid callback types are CS_CLIENTMSG_CB and CS_SERVERMSG_CB. Returns a reference to the previously installed callback of the specified type, or undef if no callback of that type exists. Passing undef as $cb_func unsets the callback for that type.
Retrieves information on the current result set. The type of information returned depends on $info_type. Currently supported values are: CS_NUM_COMPUTES, CS_NUMDATA, CS_NUMORDERCOLS, CS_ROW_COUNT.
This routine will set, retrieve or clear the values of server query-processing options.
Values for $action: CS_SET, CS_GET, CS_CLEAR
Values for $option: see p.3-170 of the OpenClient reference manual
Values for $param: When setting an option, $param can be a integer or a string. When retrieving an option, $param is set and returned. When clearing an option, $param is ignored.
Value for $type: CS_INT_TYPE if $param is of integer type, CS_CHAR_TYPE if $param is a string
Initiate a cursor command. Usage is similar to the CTlibrary ct_cursor() call, except that when in C you would pass NULL as the value for $name or $text you pass the special Perl value undef instead.
See eg/ct_cursor.pl for an example.
Define a command parameter. The %datafmt hash is used to pass the appropriate parameters to the call. The following fields are defined: name (parameter name), datatype, status, indicator and value). These fields correspond to the equivalent fields in the CS_DATAFMT structure which is used in the CTlibrary ct_param call, and includes the two additional parameters 'value' and 'indicator'.
The hash should be used like this:
%param = (name => '@acc', datatype => CS_CHAR_TYPE, status => CS_INPUTVALUE, value => 'CIS 98941', indicator => CS_UNUSED); $dbh->ct_param(\%param);
Note that ct_param() converts all parameter types to either CS_CHAR_TYPE, CS_FLOAT_TYPE, CS_DATETIME_TYPE, CS_MONEY_TYPE or CS_INT_TYPE.
See eg/ct_param.pl for an example.
Allocate a new CS_COMMAND structure. The new $dbh2 shares the CS_CONNECTION with the original $dbh, so this is really only usefull for interleaving cursor operations (see ct_cursor() above, and the section on cursors in Chapter 2 of the Open Client Client-Library/C Reference manual.
The two handles also share attributes, so setting $dbh->{UseDataTime} (for example) will also set $dbh2->{UseDateTime}.
Drops the current CS_COMMAND structure, and reallocs a new one. Returns CS_SUCCEED on successfull completion.
Calls ct_config() to change some basic parameter, like the interfaces file location.
$action can be CS_SET or CS_GET.
$property is one of the properties that is settable via ct_config() (see your OpenClient man page on ct_config() for a complete list).
$value is the input value if $action is CS_GET, and the output value if $action is CS_GET.
$type is the data type of the property that is being set or retrieved. It defaults to CS_CHAR_TYPE, but should be set to CS_INT_TYPE if an integer value (such CS_NETIO is being set or retrieved).
$ret is the return status of the ct_config() call.
$ret = ct_config(CS_SET, CS_IFILE, "/home/mpeppler/foo", CS_CHAR_TYPE); print "$ret\n"; $ret = ct_config(CS_GET, CS_IFILE, $out, CS_CHAR_TYPE); print "$ret - $out\n"; #prints 1 - /home/mpeppler/foo
cs_dt_info() allows you to set the default conversion modes for DATETIME values, and lets you query the locale database for names for dateparts.
To set the default conversion you call cs_dt_info() with a $type parameter of CS_DT_CONVFMT, and pass the conversion style you want as a string:
cs_dt_info(CS_SET, CS_DT_CONVFMT, CS_UNUSED, "CS_DATES_LONG");
See Table 2-26 in the Open Client and Open Server Common Libraries Reference Manual for details of other formats that are available.
You can query a datepart name by doing something like:
cs_dt_info(CS_GET, CS_MONTH, 3, $buf); print "$buf\n"; # Prints 'April' in the default locale
Again see the entry for cs_dt_info() in Chapter 2 of the Open Client and Open Server Common Libraries Reference Manual for details.
Runs the sql command and returns the result as a reference to an array of the rows. Each row is a reference to an array of scalars. In a LIST context, ct_sql returns an array of references to each row.
If the $doAssoc parameter is CS_TRUE, then each row is a reference to an associative array (keyed on the column names) rather than a normal array (see ct_fetch(), above).
This routine is very usefull to send SQL commands to the server that do not return rows, such as:
$dbh->ct_sql("use BugTrack");
Examples can be found in eg/ct_sql.pl.
NOTE: This routine loads all the data into memory. Memory consumption can therefore become quite important for a query that returns a large number of rows, unless the MaxRows attribute has been set.
Two additional attributes are set after calling ct_sql(): ROW_COUNT holds the number of rows affected by the command, and RC holds the return code of the last call to ct_execute().
Returns TRUE if the current result set has fetchable rows. Use like this:
$dbh->ct_execute("select * from sysprocesses"); while($dbh->ct_results($restype) == CS_SUCCEED) { next if(!$dbh->ct_fetchable($restype)); while(@dat = $dbh->ct_fetch) { print "@dat\n"; } }
#!/usr/local/bin/perl use Sybase::CTlib; ct_callback(CS_CLIENTMSG_CB, \&msg_cb); ct_callback(CS_SERVERMSG_CB, "srv_cb"); $uid = 'mpeppler'; $pwd = 'my-secret-password'; $srv = 'TROLL'; $X = Sybase::CTlib->ct_connect($uid, $pwd, $srv); $X->ct_execute("select * from sysusers"); while(($rc = $X->ct_results($restype)) == CS_SUCCEED) { next if($restype == CS_CMD_DONE || $restype == CS_CMD_FAIL || $restype == CS_CMD_SUCCEED); if(@names = $X->ct_col_names()) { print "@names\n"; } if(@types = $X->ct_col_types()) { print "@types\n"; } while(@dat = $X->ct_fetch) { print "@dat\n"; } } print "End of Results Sets\n" if($rc == CS_END_RESULTS); print "Error!\n" if($rc == CS_FAIL); sub msg_cb { my($layer, $origin, $severity, $number, $msg, $osmsg, $dbh) = @_; printf STDERR "\nOpen Client Message: (In msg_cb)\n"; printf STDERR "Message number: LAYER = (%ld) ORIGIN = (%ld) ", $layer, $origin; printf STDERR "SEVERITY = (%ld) NUMBER = (%ld)\n", $severity, $number; printf STDERR "Message String: %s\n", $msg; if (defined($osmsg)) { printf STDERR "Operating System Error: %s\n", $osmsg; } CS_SUCCEED; } sub srv_cb { my($dbh, $number, $severity, $state, $line, $server, $proc, $msg) = @_; # If $dbh is defined, then you can set or check attributes # in the callback, which can be tested in the main body # of the code. printf STDERR "\nServer message: (In srv_cb)\n"; printf STDERR "Message number: %ld, Severity %ld, ", $number, $severity; printf STDERR "State %ld, Line %ld\n", $state, $line; if (defined($server)) { printf STDERR "Server '%s'\n", $server; } if (defined($proc)) { printf STDERR " Procedure '%s'\n", $proc; } printf STDERR "Message String: %s\n", $msg; CS_SUCCEED; }
The behaviour of certain aspects of the Sybase::CTlib module can be controled via global or connection specific attributes. The global attributes are stored in the %Sybase::CTlib::Att variable, and the connection specific attributes are stored in the $dbh. To set a global attribute, you would code
If TRUE, then keep DATETIME data retrieved via ct_fetch() in native format instead of converting the data to a character string. Default: FALSE.
If TRUE, keep MONEY data retrieved via ct_fetch() in native format instead of converting the data to double precision floating point. Default: FALSE.
If TRUE, keep NUMERIC or DECIMAL data retrieved via ct_fetch() in native format, instead of converting to double precision floating point. Default: FALSE.
If non-0, limit the number of data rows that can be retrieve via ct_sql(). Default: 0.
Turns the debugging trace on or off. The $module_name should be one of Sybase::DBlib or Sybase::CTlib. The value of $bitmask determines which features are going to be traced. The following trace bits are currently recognized:
TRACE_CREATE
Trace all CTlib and/or DBlib object creations.
TRACE_DESTROY
Trace all calls to DESTROY.
TRACE_SQL
Traces all SQL language commands - (ie calls to dbcmd(), ct_execute() or ct_command().)
TRACE_RESULTS
Traces calls to dbresults()/ct_results().
TRACE_FETCH
Traces calls to dbnextrow()/ct_fetch(), and traces the values that are pushed on the stack.
TRACE_CUSROR
Trace calls to ct_cursor() (not available in Sybase::DBlib).
TRACE_PARAMS
Trace calls to ct_param() (not implemented in Sybase::DBlib).
TRACE_OVERLOAD
Trace all overloaded operations involving DateTime, Money or Numeric datatypes.
Two special trace flags are TRACE_NONE, which turns off debug tracing, and TRACE_ALL which (you guessed it!) turns everything on.
The traces are pretty obscure, but they can be useful when trying to find out what is really going on inside the program.
For the TRACE_* flags to be available in your scripts, you must load the Sybase::??lib module with the following syntax:
use Sybase::CTlib qw(:DEFAULT /TRACE/);
This tells the autoloading mechanism to import all the default symbols, plus all the trace symbols.
NOTE: This feature is turned off by default for performance reasons. You can turn it on per datatype and dbh, or via the module attribute hash (%Sybase::DBlib::Att and %Sybase::CTlib::Att).
The Sybase::CTlib and Sybase::DBlib modules include special features to handle DATETIME, MONEY, and NUMERIC/DECIMAL (CTlib only) values in their native formats correctly. What this means is that when you retrieve a date using ct_fetch() or dbnextrow() it is not converted to a string, but kept in the internal format used by the Sybase libraries. You can then manipulate this date as you see fit, and in particular 'crack' the date into it's components.
The same is true for MONEY (and for CTlib NUMERIC values), which otherwise are converted to floating point values, and hence are subject to loss of precision in certain situations. Here they are stored as MONEY values, and by using operator overloading we can give you intuitive access to the cs_calc()/dbmnyxxx() routines.
This feature has been implemented by creating new classes in both Sybase::DBlib and Sybase::CTlib: Sybase::DBlib::DateTime, Sybase::DBlib::Money, Sybase::CTlib::DateTime, Sybase::CTlib::Money and Sybase::CTlib::Numeric (hereafter referred to as DateTime, Money and Numeric). All the examples below use the CTlib module. The syntax is identical for the DBlib module, except that the Numeric class does not exist.
To create data items of these types you call:
$dbh = new Sybase::CTlib user, password; ... # code deleted # Create a new DateTime object, and initialize to Jan 1, 1995: $date = $dbh->newdate('Jan 1 1995'); # Create a new Money object $mny = $dbh->newmoney; # Default value is 0 # Create a new Numeric object $num = $dbh->newnumeric(11.111);
The DateTime class defines the following methods:
Convert to string (calls cs_convert()/dbconvert()).
'Crack' the date into its components.
Compare $date with $date2.
Add or substract $days and $msecs from $date, and returns the new date.
Compute the difference, in $days and $msecs between $date and $date2.
Calls cs_dt_info to return the string representation for a datepart. Valid dateparts are CS_MONTH, CS_SHORTMONTH and CS_DAYNAME.
NOTE: Not implemented in DBlib.
Converts a Sybase DATETIME value to a Unix time_t value. The mktime and timelocal methods assumes the date is stored in local time, timegm assumes GMT. The mktime method uses the POSIX module (note that unavailability of the POSIX module is not a fatal error.)
Both the str and the cmp methods will be called transparently when they are needed, so that
print "$date"
will print the date string correctly, and
$date1 cmp $date2
will do a comparison of the two dates, not the two strings.
crack executes cs_dt_crack()/dbdatecrack() on the date value, and returns the following list:
($year, $month, $month_day, $year_day, $week_day, $hour, $minute, $second, $millisecond, $time_zone) = $date->crack;
Compare this with the value returned by the standard Perl function localtime():
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
In addition, the values returned for the week_day can change depending on the locale that has been set.
Please see the discussion on cs_dt_crack() or dbdatecrack() in the Open Client / Open Server Common Libraries Reference Manual, chap. 2.
The Money and Numeric classes define these methods
Convert to a floating point number (calls cs_convert()/dbconvert()).
Compare two Money or Numeric values.
Set the value of $mny to $number.
Perform the calculation specified by $op on $mny and $mny2. $op is one of '+', '-', '*' or '/'.
As with the DateTime class, the str and cmp methods will be called automatically for you when required. In addition, you can perform normal arithmetic on Money or Numeric datatypes without calling the calc method explicitly.
CAVEAT! You must call the set method to assign a value to a Money/Numeric data item. If you use
$mny = 4.05
then $mny will loose its special Money or Numeric behavior and become a normal Perl data item.
When a new Numeric data item is created, the SCALE and PRECISION values are determined by the initialization. If the data item is created as part of a SELECT statement, then the SCALE and PRECISION values will be those of the retrieved item. If the item is created via the newnumeric method (either explicitly or implicitly) the SCALE and PRECISION are deduced from the initializing value. For example, $num = $dbh->newnumeric(11.111) will produce an item with a SCALE of 3 and a PRECISION of 5. This is totally transparent to the user.
Larry Wall - for Perl :-)
Tim Bunce & Andreas Koenig - for all the work on MakeMaker
Michael Peppler <mpeppler@mbay.net>
Dave Bowen & Amy Lin for help with Sybase::CTlib.
Jeffrey Wong for the Sybase::DBlib DBMONEY routines.
Numerous folks have contributed ideas and bug fixes for which they have my undying thanks :-)
The sybperl mailing list <sybperl-l@trln.lib.unc.edu> is the best place to ask questions.
2 POD Errors
The following errors were encountered while parsing the POD:
'=item' outside of any '=over'
You forgot a '=back' before '=head1'
To install Sybase::BCP, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Sybase::BCP
CPAN shell
perl -MCPAN -e shell install Sybase::BCP
For more information on module installation, please visit the detailed CPAN module installation guide.