1DBSchema::DBD(3) User Contributed Perl Documentation DBSchema::DBD(3)
2
3
4
6 DBIx::DBSchema::DBD - DBIx::DBSchema Driver Writer's Guide and Base
7 Class
8
10 perldoc DBIx::DBSchema::DBD
11
12 package DBIx::DBSchema::DBD::FooBase
13 use DBIx::DBSchema::DBD;
14 @ISA = qw(DBIx::DBSchema::DBD);
15
17 Drivers should be named DBIx::DBSchema::DBD::DatabaseName, where
18 DatabaseName is the same as the DBD:: driver for this database.
19 Drivers should implement the following class methods:
20
21 columns CLASS DBI_DBH TABLE
22 Given an active DBI database handle, return a listref of listrefs
23 (see perllol), each containing six elements: column name, column
24 type, nullability, column length, column default, and a field
25 reserved for driver-specific use.
26
27 column CLASS DBI_DBH TABLE COLUMN
28 Same as columns above, except return the listref for a single
29 column. You can inherit from DBIx::DBSchema::DBD to provide this
30 function.
31
32 primary_key CLASS DBI_DBH TABLE
33 Given an active DBI database handle, return the primary key for the
34 specified table.
35
36 unique CLASS DBI_DBH TABLE
37 Deprecated method - see the indices method for new drivers.
38
39 Given an active DBI database handle, return a hashref of unique
40 indices. The keys of the hashref are index names, and the values
41 are arrayrefs which point a list of column names for each. See
42 "HASHES OF LISTS" in perldsc and DBIx::DBSchema::Index.
43
44 index CLASS DBI_DBH TABLE
45 Deprecated method - see the indices method for new drivers.
46
47 Given an active DBI database handle, return a hashref of (non-
48 unique) indices. The keys of the hashref are index names, and the
49 values are arrayrefs which point a list of column names for each.
50 See "HASHES OF LISTS" in perldsc and DBIx::DBSchema::Index.
51
52 indices CLASS DBI_DBH TABLE
53 Given an active DBI database handle, return a hashref of all
54 indices, both unique and non-unique. The keys of the hashref are
55 index names, and the values are again hashrefs with the following
56 keys:
57
58 name - Index name (redundant)
59 using - Optional index method
60 unique - Boolean indicating whether or not this is a unique index
61 columns - List reference of column names (or expressions)
62
63 (See FS::DBIx::DBSchema::Index)
64
65 New drivers are advised to implement this method, and existing
66 drivers are advised to (eventually) provide this method instead of
67 index and unique.
68
69 For backwards-compatibility with current drivers, the base
70 DBIx::DBSchema::DBD class provides an indices method which uses the
71 old index and unique methods to provide this data.
72
73 default_db_catalog
74 Returns the default database catalog for the DBI table_info
75 command. Inheriting from DBIx::DBSchema::DBD will provide the
76 default empty string.
77
78 default_db_schema
79 Returns the default database schema for the DBI table_info command.
80 Inheriting from DBIx::DBSchema::DBD will provide the default empty
81 string.
82
83 constraints CLASS DBI_DBH TABLE
84 Given an active DBI database handle, return the constraints
85 (currently, foreign keys) for the specified table, as a list of
86 hash references.
87
88 Each hash reference has the following keys:
89
90 constraint - contraint name
91 columns - List refrence of column names
92 table - Foreign taable name
93 references - List reference of column names in foreign table
94 match -
95 on_delete -
96 on_update -
97 column_callback DBH TABLE_NAME COLUMN_OBJ
98 Optional callback for driver-specific overrides to SQL column
99 definitions.
100
101 Should return a hash reference, empty for no action, or with one or
102 more of the following keys defined:
103
104 effective_type - Optional type override used during column
105 creation.
106
107 explicit_null - Set true to have the column definition declare NULL
108 columns explicitly
109
110 effective_default - Optional default override used during column
111 creation.
112
113 effective_local - Optional local override used during column
114 creation.
115
116 add_column_callback DBH TABLE_NAME COLUMN_OBJ
117 Optional callback for additional SQL statments to be called when
118 adding columns to an existing table.
119
120 Should return a hash reference, empty for no action, or with one or
121 more of the following keys defined:
122
123 effective_type - Optional type override used during column
124 creation.
125
126 effective_null - Optional nullability override used during column
127 creation.
128
129 sql_after - Array reference of SQL statements to be executed after
130 the column is added.
131
132 alter_column_callback DBH TABLE_NAME OLD_COLUMN_OBJ NEW_COLUMN_OBJ
133 Optional callback for overriding the SQL statments to be called
134 when altering columns to an existing table.
135
136 Should return a hash reference, empty for no action, or with one or
137 more of the following keys defined:
138
139 sql_alter - Alter SQL statement(s) for changing everything about a
140 column. Specifying this overrides processing of individual changes
141 (type, nullability, default, etc.).
142
143 sql_alter_type - Alter SQL statement(s) for changing type and
144 length (there is no default).
145
146 sql_alter_null - Alter SQL statement(s) for changing nullability to
147 be used instead of the default.
148
149 column_value_needs_quoting COLUMN_OBJ
150 Optional callback for determining if a column's default value
151 require quoting. Returns true if it does, false otherwise.
152
154 You can define a %typemap array for your driver to map "standard" data
155 types to database-specific types. For example, the MySQL TIMESTAMP
156 field has non-standard auto-updating semantics; the MySQL DATETIME type
157 is what other databases and the ODBC standard call TIMESTAMP, so one of
158 the entries in the MySQL %typemap is:
159
160 'TIMESTAMP' => 'DATETIME',
161
162 Another example is the Pg %typemap which maps the standard types BLOB
163 and LONG VARBINARY to the Pg-specific BYTEA:
164
165 'BLOB' => 'BYTEA',
166 'LONG VARBINARY' => 'BYTEA',
167
168 Make sure you use all uppercase-keys.
169
171 Ivan Kohler <ivan-dbix-dbschema@420.am>
172
174 Copyright (c) 2000-2005 Ivan Kohler Copyright (c) 2007-2017 Freeside
175 Internet Services, Inc. All rights reserved. This program is free
176 software; you can redistribute it and/or modify it under the same terms
177 as Perl itself.
178
181 DBIx::DBSchema, DBIx::DBSchema::DBD::mysql, DBIx::DBSchema::DBD::Pg,
182 DBIx::DBSchema::Index, DBI, DBI::DBD, perllol, "HASHES OF LISTS" in
183 perldsc
184
185
186
187perl v5.36.0 2023-01-20 DBSchema::DBD(3)