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.IX Title "DlfSchema 3pm"
.TH DlfSchema 3pm 2025-09-28 "Lire 2.1.1" "LogReport's Lire Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.nh
.SH NAME
Lire::DlfSchema \- Interface to Lire DLF Schema XML specifications
.SH SYNOPSIS
.IX Header "SYNOPSIS"
In DLF converters:
.PP
.Vb 1
\&    use Lire::DlfSchema;
\&
\&    my $schema = Lire::DlfSchema::load_schema( "email" );
\&    my $fields = $schema\->fields();
\&
\&    my $dlf_id = $schema\->field( \*(Aqdlf_id\*(Aq );
\&    my $dlf_src = $schema\->field( \*(Aqdlf_source\*(Aq );
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
This module is the interface to the Lire DLF Schemas defined in XML
files. A schema defines the order of the fields along with their
names, descriptions and types.
.PP
Each DlfSchema have at least two predefined fields:
.IP dlf_id 4
.IX Item "dlf_id"
This is an integer which uniquely identify a DLF record in its stream.
Its used to link the record to its extended schemas fields and also to
link the record to the derived schemas records.
.IP dlf_source 4
.IX Item "dlf_source"
This is an identifier which can be used to track the record the
ImportJob that created it.
.SH "ACCESSING A SCHEMA OBJECT"
.IX Header "ACCESSING A SCHEMA OBJECT"
The way to access a schema for a superservice is through the
\&\fBload_schema()\fR module function. You use it like this:
.PP
.Vb 1
\&    my $schema = Lire::DlfSchema::load_schema( $superservice);
.Ve
.PP
This function will return a schema object which can then be used to
query information about the schema. This function will \fBdie()\fR on error.
.ie n .SS "has_superservice( $superservice )"
.el .SS "has_superservice( \f(CW$superservice\fP )"
.IX Subsection "has_superservice( $superservice )"
Returns true if there is superservice named \f(CW$schema_name\fR available. An
error will be thrown if the schema name isn\*(Aqt valid for a superservice.
.ie n .SS "has_schema( $schema_name )"
.el .SS "has_schema( \f(CW$schema_name\fP )"
.IX Subsection "has_schema( $schema_name )"
Returns true if there is \f(CW$schema_name\fR available. An error will be
thrown if the schema name isn\*(Aqt valid.
.SS \fBsuperservices()\fP
.IX Subsection "superservices()"
Returns the name of the available superservices in an array.
.SS \fBschemas()\fP
.IX Subsection "schemas()"
Returns the name of the available schemas in an array.
.SH "SCHEMA OBJECT METHODS"
.IX Header "SCHEMA OBJECT METHODS"
.SS \fBid()\fP
.IX Subsection "id()"
.Vb 1
\&    my $id = $schema\->id();
.Ve
.PP
This method will return the id of the schema. This will be the
superservice\*(Aqs name for superservice\*(Aqs main schema. (There are other
types of schemas (derived and extended schemas) for which the id will be
different than the superservice\*(Aqs name.)
.SS \fBsuperservice()\fP
.IX Subsection "superservice()"
.Vb 1
\&    my $super = $schema\->superservice();
.Ve
.PP
This method will return the superservice\*(Aqs name of the schema.
.SS "title( [$new_title] )"
.IX Subsection "title( [$new_title] )"
This method will return (or change) the human readable title of the
schema. (This is the content of the title element in the XML
specification.)
.SS "description( [$new_description] )"
.IX Subsection "description( [$new_description] )"
This method will return (or change) the description of the schema.
(This is the content of the description element in the XML
specification.) Be aware that this will most likely contain DocBook
markup.
.SS \fBfield_by_pos()\fP
.IX Subsection "field_by_pos()"
.Vb 1
\&    my $field = $schema\->field_by_pos( 0 );
.Ve
.PP
This method takes an integer as parameter and return the field at that
position in the schema. Fields are indexed starting at 0. This method
will \fBdie()\fR if an invalid position is passed as parameter.
.PP
The method returns a \fBLire::Field\fR\|(3pm) object.
.ie n .SS "add_field( $field )"
.el .SS "add_field( \f(CW$field\fP )"
.IX Subsection "add_field( $field )"
Adds the Lire::Field \f(CW$field\fR to this schema.
.SS \fBhas_field()\fP
.IX Subsection "has_field()"
.Vb 3
\&    if ( $schema\->has_field( \*(Aqtest ) ) { 
\&        print "schema has field \*(Aqtest\*(Aq\en"; 
\&    }
.Ve
.PP
This method takes a string as parameter and returns a boolean value.
That value will be true if there is a field in the schema with that
name, it will be false otherwise.
.SS \fBfield()\fP
.IX Subsection "field()"
.Vb 1
\&    my $field = $schema\->field( \*(Aqfrom_email\*(Aq );
.Ve
.PP
This method takes a field\*(Aqs name as parameter and returns the
\&\fBLire::Field\fR\|(3pm) object describing that field in the schema. The
method will \fBdie()\fR if there is no field with that name in the schema.
.SS \fBfields()\fP
.IX Subsection "fields()"
.Vb 2
\&    my $fields = $schema\->fields();
\&    my @fields = $schema\->fields();
.Ve
.PP
In array context, this method will return an array containing all the
fields (as \fBLire::Field\fR\|(3pm) objects) in the schema. The order of the
fields in the array is the order of the fields in the schema.
.PP
In scalar context, it will return an array reference. This method is
more efficient than creating an array. DO NOT MODIFY THE RETURNED
ARRAY.
.SS \fBfield_names()\fP
.IX Subsection "field_names()"
Returns the name of the fields in this schema. The names are in the
same order than the fields.
.SS \fBfield_count()\fP
.IX Subsection "field_count()"
.Vb 1
\&    my $number_of_field = $schema\->field_count;
.Ve
.PP
This method returns the number of fields in the schema.
.SS \fBtimestamp_field()\fP
.IX Subsection "timestamp_field()"
.Vb 1
\&    my $time_field = $schema\->timestamp_field;
.Ve
.PP
This method will return the \fBLire::Field\fR\|(3pm) object representing the
timestamp field in the schema. The timestamp field is the one that
defines the sort order of the DLF records.
.SS \fBis_schema_compatible()\fP
.IX Subsection "is_schema_compatible()"
.Vb 1
\&    if ( $schema\->is_schema_compatible( $other_schema ) ) {
\&
\&    }
.Ve
.PP
This method takes a \fBLire::DlfSchema\fR\|(3pm) object as parameter and returns a
boolean value. That value will be true if the schema passed as parameter is
compatible with the other, it will be false otherwise.
.PP
For a superservice\*(Aqs schema, the only compatible schema is an object
representing the same superservice\*(Aqs schema.
.ie n .SS "can_join_schema( $schema )"
.el .SS "can_join_schema( \f(CW$schema\fP )"
.IX Subsection "can_join_schema( $schema )"
Returns true if \f(CW$schema\fR can be joined with this schema. For a
DlfSchema, this will be true only when \f(CW$schema\fR is an ExtendedSchema of
this schema.
.SH "SQL Related Methods"
.IX Header "SQL Related Methods"
These methods are used to map DLF record into SQL tables.
.SS \fBsql_table()\fP
.IX Subsection "sql_table()"
Returns the SQL table used to hold the DLF records of this schema.
.ie n .SS "create_sql_schema( $dlf_store, [ $remove ] )"
.el .SS "create_sql_schema( \f(CW$dlf_store\fP, [ \f(CW$remove\fP ] )"
.IX Subsection "create_sql_schema( $dlf_store, [ $remove ] )"
This will create the SQL schemas necessary to hold the DLF records for
this schema in the Lire::DlfStore. If \f(CW$remove\fR is true, a DROP TABLE
will be done before creating the schema.
.ie n .SS "needs_sql_schema_migration( $dlf_store )"
.el .SS "needs_sql_schema_migration( \f(CW$dlf_store\fP )"
.IX Subsection "needs_sql_schema_migration( $dlf_store )"
This method will return true if the SQL schema isn\*(Aqt up\-to\-date in the
DlfStore. The method \fBmigrate_sql_schema()\fR can be used to bring the
schema up to date.
.ie n .SS "migrate_sql_schema( $dlf_store )"
.el .SS "migrate_sql_schema( \f(CW$dlf_store\fP )"
.IX Subsection "migrate_sql_schema( $dlf_store )"
Updates the SQL schemas to the current version.
.ie n .SS "dlf_query( $sort_spec )"
.el .SS "dlf_query( \f(CW$sort_spec\fP )"
.IX Subsection "dlf_query( $sort_spec )"
Returns a Lire::DlfQuery object which can be use to return all DLF
records sorted according to \f(CW$sort_spec\fR. Sort spec is a white\-space
delimited list of sort field names. They must be present in the
current schema. If the field\*(Aqs name is prefixed by \*(Aq\-\*(Aq, descending
sort order will be used.
.SS \fBinsert_sql_query()\fP
.IX Subsection "insert_sql_query()"
Returns the INSERT SQL statement that should be used to insert DLF
records in the stream. A DBI::st handle prepared with that query needs
to be passed as parameter to \fBexecute_insert_query()\fR.
.ie n .SS "sql_clean_query( $with_time )"
.el .SS "sql_clean_query( \f(CW$with_time\fP )"
.IX Subsection "sql_clean_query( $with_time )"
Returns the DELETE statement that can be use to delete the DLF records
in this schema. If \f(CW$with_time\fR is true, the query can be use for
selective cleaning. One bind timestamp parameter should be passed when
the query is executed and all records which are older than this
timestamp will be deleted.
.SS \fBsql_clean_period_query()\fP
.IX Subsection "sql_clean_period_query()"
Returns the DELETE statement that can be use to delete the DLF records
in this schema. The query should be passed two bind parameters. These
parameters will be the time boundaries between which records should be
deleted from the schema.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBLire::Field\fR\|(3pm), \fBLire::ExtendedSchema\fR\|(3pm), \fBLire::DlfConverter\fR\|(3pm),
\&\fBLire::DerivedSchema\fR\|(3pm)
.SH AUTHOR
.IX Header "AUTHOR"
.Vb 1
\&  Francis J. Lacoste <flacoste@logreport.org>
.Ve
.SH VERSION
.IX Header "VERSION"
\&\f(CW$Id:\fR DlfSchema.pm,v 1.58 2006/07/23 13:16:28 vanbaal Exp $
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright (C) 2001, 2002, 2004 Stichting LogReport Foundation LogReport@LogReport.org
.PP
This file is part of Lire.
.PP
Lire is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
.PP
This program 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 General Public License for more details.
.PP
You should have received a copy of the GNU General Public License
along with this program (see COPYING); if not, check with
http://www.gnu.org/copyleft/gpl.html.