Difference between revisions of "API:EPrints/Database/Oracle"

From EPrints Documentation
Jump to: navigation, search
Line 248: Line 248:
  $boolean = $db->has_column( $table, $column )
  $boolean = $db->has_column( $table, $column )
Return <tt>true</tt> if the named database <tt>$table</tt> has the named  <tt>$column</tt>.
Return <tt>true</tt> if the named database <tt>$table</tt> has the named  <tt>$column</tt>.
Default method from [[API:EPrints/Database|EPrints::Database]] this is really slow and this  is much faster.
<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
Line 310: Line 312:
  $sql = $db-&gt;prepare_regexp( $col, $_value )
  $sql = $db-&gt;prepare_regexp( $col, $value )
The syntax used for regular expressions varies across databases. This method takes two quoted string and returns a SQL expression that will apply the quoted regexp <tt>$value</tt> to the quoted column <tt>$col</tt>.
Oracle use the syntax:
REGEXP_LIKE ($col, $value)
For the quoted regexp <tt>$value</tt> and the quoted column <tt>$col</tt>.
<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>

Revision as of 20:08, 25 December 2021

EPrints 3 Reference: Directory Structure - Metadata Fields - Repository Configuration - XML Config Files - XML Export Format - EPrints data structure - Core API - Data Objects


Latest Source Code (3.4, 3.3) | Revision Log | Before editing this page please read Pod2Wiki


EPrints::Database::Oracle - custom database methods for Oracle DB

User Comments


These settings are the default settings for the free Oracle developer version:

 # Oracle driver settings for database.pl
 $c->{dbdriver} = "Oracle";
 $c->{dbhost} = "localhost";
 $c->{dbsid} = "XE;
 $c->{dbuser} = "HR";
 $c->{dbpass} = "HR";

User Comments


Oracle database wrapper for Oracle DB version 9+.

User Comments

Setting up Oracle

Enable the HR user in Oracle XE.

Set the ORACLE_HOME and ORACLE_SID environment variables. To add these globally edit /etc/profile.d/oracle.sh (for XE edition):

 export ORACLE_HOME="/usr/lib/oracle/xe/app/oracle/product/10.2.0/server"
 export ORACLE_SID="XE"

(Will need to relog to take effect)

User Comments

Oracle-specific Annoyances

Use the GQLPlus wrapper from http://gqlplus.sourceforge.net/ instead of sqlplus.

Oracle will uppercase any identifiers that aren't quoted and is case sensitive, hence mixing quoted and unquoted identifiers will lead to problems.

Oracle does not support LIMIT().

Oracle does not support AUTO_INCREMENT (MySQL) nor SERIAL (Postgres).

Oracle won't ORDER BY LOBS.

Oracle requires special means to insert values into CLOB/BLOB.

Oracle doesn't support AS when aliasing.

When specifying char column lengths use (n char) to define character semantics. Otherwise oracle uses the nls_length_semantics setting to determine whether you meant bytes or characters.

DBD::Oracle can crash when using PERL_USE_SAFE_PUTENV-compiled Perls, see http://www.eprints.org/tech.php/13984.html.

User Comments


User Comments

epadmin create

User Comments

$name = $db->index_name( $table, @columns )

User Comments


User Comments



Connects to the database. Also sets LongReadLen to 128*1024.

User Comments


$sth = $db->prepare_select( $sql, [ %options ] )

Prepare a SELECT statement $sql and return a handle to it. After preparing a statement use execute() to execute it.

Returns a DBI statement handle.

The LIMIT SQL keyword is not universally supported, to specify this use the limit option.


   limit - limit the number of rows returned
   offset - return limit number of rows after offset

User Comments


$success = $db->create_archive_tables()

Creates all the SQL tables for all datasets.

User Comments


$version = $db->get_server_version

Returns the database server version.

User Comments


$real_type = $db->get_column_type( $name, $type, $not_null, [ $length ] )

Returns a SQL column definition for $name of type $type. If $not_null is true the column will be set to NOT NULL. For column types that require a length use $length.

$type is the SQL type. The types are constants defined by this module, to import them use:

 use EPrints::Database qw( :sql_types );

Supported types (n = requires LENGTH argument):




Floating-point data: SQL_REAL, SQL_DOUBLE.

Time data: SQL_DATE, SQL_TIME.

User Comments


@tables = $db->get_tables

Return a list of all the tables in the database.

User Comments


$boolean = $db->has_sequence( $name )

Return true if a sequence of the given $<name> exists in the database.

User Comments


$boolean = $db->has_column( $table, $column )

Return true if the named database $table has the named $column.

Default method from EPrints::Database this is really slow and this is much faster.

User Comments


$boolean = $db->has_table( $table )

Returns boolean dependent on whether the named $table exists in the database.

User Comments


$n = $db->counter_current( $counter )

Return the value of the previous counter_next on $counter.

Oracle doesn't support getting the current value of a sequence so this method always returns undef.

User Comments


$id = $db->quote_identifier( @columns )

This method quotes and returns the given database identifier. If more than one name is supplied joins them using the correct database joining character (typically .).

Oracle restricts identifiers to:

  30 chars long
  start with a letter [a-z]
  { [a-z0-9], $, _, # }
  case insensitive
  not a reserved word (unless quoted?)

Identifiers longer than 30 characters will be abbreviated to the first 5 characters of the identifier and 25 characters from an MD5 derived from the identifier. This should make name collisions unlikely.

User Comments


$sql = $db->prepare_regexp( $col, $value )

Oracle use the syntax:

REGEXP_LIKE ($col, $value)

For the quoted regexp $value and the quoted column $col.

User Comments


$str = $db->quote_binary( $value )

Oracle requires transforms of binary data to work correctly.

This method should be called on data $value containing null bytes or back-slashes before being passed on quote_value.

User Comments


$str = $db->quote_ordervalue( $field, $value )

Oracle can't order by CLOBS so need special treatment when creating the ordervalues tables. This method fixes up $value to limit it to 1000 characters (4000 bytes) or returns undef if $value is not defined.

User Comments


$name = $db->index_name( $table, @cols )

Should return the name of the first index that starts with named columns @cols in the named $table. However, this is not supported by Oracle so always returns 1.

User Comments


$sql = $db->sql_AS()

Returns the syntactic glue to use when aliasing. Oracle does not require a phrase so just returns a space character.

User Comments


$boolean = $db->retry_error()

Returns a boolean for whether the database error is a retry error. Based on whether DBI#err code is 3113 or 3114.

User Comments


$type_info = $db->type_info( $data_type )

See DBI/type_info. Oracle has is own type information mappings.

User Comments


© Copyright 2022 University of Southampton.

EPrints 3.4 is supplied by EPrints Services.



This file is part of EPrints 3.4 http://www.eprints.org/.

EPrints 3.4 and this file are released under the terms of the GNU Lesser General Public License version 3 as published by the Free Software Foundation unless otherwise stated.

EPrints 3.4 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with EPrints 3.4. If not, see http://www.gnu.org/licenses/.

User Comments