Dbi Error String
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Related Modules Rose::DB::Object DBIx::Class Class::DBI more... By perlmonks.org CPAN RT New 14 Open 11 Stalled 4 View/Report Bugs Module Version: 1.636 perl dbi close database handle Source NAME SYNOPSIS GETTING HELP General Mailing Lists dbi ping IRC Online Reporting a Bug NOTES DESCRIPTION Architecture of a DBI Application Notation and Conventions Outline perl dbi connect error Usage General Interface Rules & Caveats Naming Conventions and Name Space SQL - A Query Language Placeholders and Bind Values THE DBI PACKAGE AND CLASS DBI
Dbi Error Fatal
Constants DBI Class Methods parse_dsn connect connect_cached available_drivers installed_drivers installed_versions data_sources trace visit_handles DBI Utility Functions data_string_desc data_string_diff data_diff neat neat_list looks_like_number hash sql_type_cast DBI Dynamic Attributes $DBI::err $DBI::errstr $DBI::state $DBI::rows $DBI::lasth METHODS COMMON TO ALL HANDLES err errstr state set_err trace trace_msg func can parse_trace_flags parse_trace_flag private_attribute_info swap_inner_handle visit_child_handles ATTRIBUTES COMMON TO dbi raiseerror ALL HANDLES Warn Active Executed Kids ActiveKids CachedKids Type ChildHandles CompatMode InactiveDestroy AutoInactiveDestroy PrintWarn PrintError RaiseError HandleError HandleSetErr ErrCount ShowErrorStatement TraceLevel FetchHashKeyName ChopBlanks LongReadLen LongTruncOk TaintIn TaintOut Taint Profile ReadOnly Callbacks private_your_module_name_* DBI DATABASE HANDLE OBJECTS Database Handle Methods clone data_sources do last_insert_id selectrow_array selectrow_arrayref selectrow_hashref selectall_arrayref selectall_array selectall_hashref selectcol_arrayref prepare prepare_cached commit rollback begin_work disconnect ping get_info table_info column_info primary_key_info primary_key foreign_key_info statistics_info tables type_info_all type_info quote quote_identifier take_imp_data Database Handle Attributes AutoCommit Driver Name Statement RowCacheSize Username DBI STATEMENT HANDLE OBJECTS Statement Handle Methods bind_param bind_param_inout bind_param_array execute execute_array execute_for_fetch fetchrow_arrayref fetchrow_array fetchrow_hashref fetchall_arrayref fetchall_hashref finish rows bind_col bind_columns dump_results Statement Handle Attributes NUM_OF_FIELDS NUM_OF_PARAMS NAME NAME_lc NAME_uc NAME_hash NAME_lc_hash NAME_uc_hash TYPE PRECISION SCALE NULLABLE CursorName Database Statement ParamValues ParamTypes ParamArrays RowsInCache FURTHER INFORMATION Catalog Methods Transactions Handling BLOB / LONG / Memo Fields Simple Examples Threads and Thread Safety Signal Handling and Canceling Operations Subclassing the DBI Memory Leaks TRACING Trace Settings Trace Leve
RecentThreads NewestNodes Donate What'sNew on Apr 14, 2000 at 03:36UTC ( #7568=perltutorial: print w/replies, xml ) Need Help?? Tricks with DBI 1. Check for database errors. You're going to run into errors with databases for similar perl dbi escape reasons that you do when using system calls and the like. And
Perl Dbi Autocommit
just as you should always check the return code of your system calls, so should you always
Perl Dbi Execute Error Handling
check the return status of your database calls. The easiest way to do this is by setting DBI's RaiseError attribute to 1; first connect to the database (and check http://search.cpan.org/perldoc/DBI the return), then set the RaiseError attribute: my $dbh = DBI->connect('foo', 'bar', 'baz', 'mysql') or die "Can't connect: ", $DBI::errstr; $dbh->{RaiseError} = 1; [download] By doing this, you ensure that any database error will cause a die. Why is this good? Because generally, if you're writing a database application and you have a database error, you don't want http://www.perlmonks.org/?node_id=7568 to continue as if nothing happened. :) (Besides, you can always catch the die in an eval; just make sure that you handle the errors rather than ignoring them.) The other way to check for errors, of course, is to check the return of each method call, eg.: my $sth = $dbh->prepare("select id from foo") or die "Can't prepare: ", $dbh->errstr; $sth->execute or die "Can't execute: ", $dbh->errstr; [download] So as not to make your code one big C-like mess of error checking, though, you might as well just use RaiseError. 2. Use placeholders instead of literal values. This is covered pretty thoroughly in What are placeholders in DBI. Suffice it to say here, then, that you should use placeholders instead of literal values. Always (or pretty much, at least). And, for the same reasons, you should use prepare_cached instead of prepare. 3. The fastest way to fetch. When you execute a SELECT statement, you want to get the data back as quickly as possible. The fastest way to do this is t
Check the returns from DBI callsRaiseErrorTest inserts/updates workedProtect calls you expect could legitimately fail with evalsUse transactions, protect http://www.easysoft.com/developer/languages/perl/dbi-debugging.html them with eval and commit or roll them back after the evalConsider adding comments to SQLWhat you get in DBI out of the box to http://zetcode.com/db/mysqlperl/err/ help youDBIx::Log4perl Advantages of using DBIx::Log4perlWhere to get DBIx::Log4perlDBIx::Log4perl dependenciesDBIx::Log4perl documentationDBIx::Log4perl quick startExample DBIx::Log4perl outputCatching errors with DBIx::Log4perlAdding additional error logging to your Perl scriptLog4perl perl dbi configuration fileChanging the default logging in DBIx::Log4perlLogging only SQL and parametersAppendix A: ResourcesIntroductionYou’ve read our other Perl tutorials, installed Perl DBI and a DBD and have started writing your application but it is not working properly. What can you do? This tutorial ignores syntax errors in your Perl (which dbi error string you can easily track down with perl -cw) and concentrates on locating those tough to find SQL, incorrect use of the DBI interface, transaction and logic errors.Good DBI programming practiseCheck the returns from DBI callsTest the return from DBI method calls return a success value. DBI->connect("dbi:ODBC:mydsn", "xxx", "yyy") or die "$DBI::errstr"; Normally this is a true and non-zero value, but in some cases it is a true but zero value e.g. DBDs will return a true value for an insert operation that inserts zero rows, but if you know the insert should insert a row, you test the returned value is true and not "0E0" (which is true but zero). See the next section, "RaiseError" and "Test inserts worked".RaiseErrorThe handle attribute RaiseError is, by default, turned off. When the RaiseError attribute is turned on for a handle, it causes die to be called (or your HandleError routi
native database engine error message from the last DBI method called. $h->state()Returns a state code in the standard SQLSTATE five character format. The above three methods deal with error messages. DBI dynamic attributeDescription $DBI::errEquivalent to $h->err() $DBI::errstrEquivalent to $h->errstr() $DBI::stateEquivalent to $h->state() The second table gives a list of DBI dynamic attributes, which are related to error handling. These attributes have a short lifespan. They should be used immediately after the method that might cause an error. Default error handling By default, the errors are returned by Perl DBI methods. #!/usr/bin/perl use strict; use DBI; my $dsn = "dbi:mysql:dbname=mydb"; my $user = "user12"; my $password = "34klq*"; my $dbh = DBI->connect($dsn, $user, $password) or die "Can't connect to database: $DBI::errstr"; my $sth = $dbh->prepare( q{ SELECT Id, Name, Price FROM Cars } ) or die "Can't prepare statement: $DBI::errstr"; my $rc = $sth->execute() or die "Can't execute statement: $DBI::errstr"; while (my($id, $name, $price) = $sth->fetchrow()) { print "$id $name $price\n"; } # check for problems which may have terminated the fetch early warn $DBI::errstr if $DBI::err; $sth->finish(); $dbh->disconnect(); In the first script we deal with the default behaviour of returning error codes. my $dbh = DBI->connect($dsn, $user, $password) or die "Can't connect to database: $DBI::errstr"; We call the connect() method to create a database connection. If the attempt fails, the method returns undef and sets both $DBI::err and $DBI::errstr attributes. The die() method prints the error message in case of a failure and terminates the script. my $sth = $dbh->prepare( q{ SELECT Id, Name, Price FROM Cars } ) or die "Can't prepare statement: $DBI::errstr"; We call the prepare() statement. If the method fails, the die() method prints an error message and terminates the script. my $rc = $sth->execute() or die "Can't execute statement: $DBI::errstr"; Again. We call the execute() method and check for errors. The method returns