From ecb17d56f80ce1e4b86c14bebee53916cda9d889 Mon Sep 17 00:00:00 2001
From: Daniel Rios <dr2@sanger.ac.uk>
Date: Thu, 23 Feb 2006 14:51:33 +0000
Subject: [PATCH] Added method to allow the addition of a LIMIT clause
depending the database, and methods to convert from date to seconds and from
seconds to date due to the different functions in each database system
---
modules/Bio/EnsEMBL/DBSQL/DBConnection.pm | 112 ++++++++++++++++++++++
1 file changed, 112 insertions(+)
diff --git a/modules/Bio/EnsEMBL/DBSQL/DBConnection.pm b/modules/Bio/EnsEMBL/DBSQL/DBConnection.pm
index c483b412bb..52046a232d 100644
--- a/modules/Bio/EnsEMBL/DBSQL/DBConnection.pm
+++ b/modules/Bio/EnsEMBL/DBSQL/DBConnection.pm
@@ -620,6 +620,118 @@ sub disconnect_if_idle {
return 0;
}
+
+=head2 add_limit_clause
+
+ Arg [1] : string $sql
+ Arg [2] : int $max_number
+ Example : my $new_sql = $dbc->add_limit_clause($sql,$max_number);
+ Description: Giving an SQL statement, it adds a limit clause, dependent on the database
+ (in MySQL, should add a LIMIT at the end, MSSQL uses a TOP clause)
+ Returntype : String containing the new valid SQL statement
+ Exceptions : none
+ Caller : general
+ Status : at risk
+
+=cut
+
+
+sub add_limit_clause{
+ my $self = shift;
+ my $sql = shift;
+ my $max_number = shift;
+
+ my $new_sql = '';
+ if ($self->driver eq 'mysql'){
+ $new_sql = $sql . ' LIMIT ' . $max_number;
+ }
+ elsif ($self->driver eq 'odbc'){
+ #need to get anything after the SELECT statement
+ $sql =~ /select(.*)/i;
+ $new_sql = 'SELECT TOP ' . $max_number . $1;
+ }
+ else{
+ warning("Not possible to convert $sql to an unknow database driver: ", $self->driver, " no limit applied");
+ $new_sql = $sql;
+ }
+ return $new_sql;
+}
+
+
+=head2 from_date_to_seconds
+
+ Arg [1] : date $date
+ Example : my $string = $dbc->from_date_to_seconds($date);
+ Description: Giving a string representing a column of type date
+ applies the database function to convert to the number of seconds from 01-01-1970
+ Returntype : string
+ Exceptions : none
+ Caller : general
+ Status : at risk
+
+=cut
+
+sub from_date_to_seconds{
+ my $self= shift;
+ my $column = shift;
+
+ my $string;
+ if ($self->driver eq 'mysql'){
+ $string = "UNIX_TIMESTAMP($column)";
+ }
+ elsif ($self->driver eq 'odbc'){
+ $string = "DATEDIFF(second,'JAN 1 1970',$column)";
+ }
+ else{
+ warning("Not possible to convert $column due to an unknown database driver: ", $self->driver);
+ return '';
+ }
+ return $string;
+}
+
+
+=head2 from_seconds_to_date
+
+ Arg [1] : int $seconds
+ Example : my $string = $dbc->from_seconds_to_date($seconds);
+ Description: Giving an int representing number of seconds
+ applies the database function to convert to a date
+ Returntype : string
+ Exceptions : none
+ Caller : general
+ Status : at risk
+
+=cut
+
+sub from_seconds_to_date{
+ my $self= shift;
+ my $seconds = shift;
+
+ my $string;
+ if ($self->driver eq 'mysql'){
+ if ($seconds){
+ $string = "from_unixtime( ".$seconds.")";
+ }
+ else{
+ $string = "\"0000-00-00 00:00:00\"";
+ }
+ }
+ elsif ($self->driver eq 'odbc'){
+ if ($seconds){
+ $string = "DATEDIFF(date,'JAN 1 1970',$seconds)";
+ }
+ else{
+ $string = "\"0000-00-00 00:00:00\"";
+ }
+ }
+ else{
+ warning("Not possible to convert $seconds due to an unknown database driver: ", $self->driver);
+ return '';
+
+ }
+ return $string;
+}
+
####
#deprecated functions
####
--
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