importedkeys (Database Toolbox)

Get information about imported foreign keys

Syntax

i = importedkeys(dbmeta, 'cata', 'sch')
i = importedkeys(dbmeta, 'cata', 'sch', 'tab')

Description

i = importedkeys(dbmeta, 'cata', 'sch') returns the foreign imported key information, that is, information about fields that reference primary keys in other tables, in the schema sch, of the catalog cata, for the database whose database metadata object is dbmeta, where dbmeta was created using dmd.

i = importedkeys(dbmeta, 'cata', 'sch', 'tab') returns the foreign imported key information, that is, information about fields in the table tab, that reference primary keys in other tables, in the schema sch, of the catalog cata, for the database whose database metadata object is dbmeta, where dbmeta was created using dmd.

Examples

Type

i = importedkeys(dbmeta,'orcl','SCOTT')

MATLAB returns

i = 
  Columns 1 through 7
    'orcl'   'SCOTT'   'DEPT'   'DEPTNO'    'orcl'    'SCOTT'    'EMP'
  Columns 8 through 13
    'DEPTNO'    '1'    'null'    '1'    'FK_DEPTNO'    'PK_DEPT'

In this example:

dbmeta is the database metadata object.
orcl is the catalog cata.
SCOTT is the schema sch.

The results show the foreign imported key information as described in the following table.

Column
Description
Value

1
Catalog containing primary key, referenced by foreign imported key
orcl

2
Schema containing primary key, referenced by foreign imported key
SCOTT

3
Table containing primary key, referenced by foreign imported key
DEPT

4
Column name of primary key, referenced by foreign imported key
DEPTNO

5
Catalog that has foreign imported key
orcl

6
Schema that has foreign imported key
SCOTT

7
Table that has foreign imported key
EMP

8
Foreign key column name, that is the column name that references the primary key in another table
DEPTNO

9
Sequence number within foreign key
1

10
Update rule, that is, what happens to the foreign key when the primary key is updated.
null

11
Delete rule, that is, what happens to the foreign key when the primary key is deleted.
1

12
Foreign imported key name
FK_DEPTNO

13
Primary key name in referenced table
PK_DEPT

Column	Description	Value
1	Catalog containing primary key, referenced by foreign imported key	`orcl`
2	Schema containing primary key, referenced by foreign imported key	`SCOTT`
3	Table containing primary key, referenced by foreign imported key	`DEPT`
4	Column name of primary key, referenced by foreign imported key	`DEPTNO`
5	Catalog that has foreign imported key	`orcl`
6	Schema that has foreign imported key	`SCOTT`
7	Table that has foreign imported key	`EMP`
8	Foreign key column name, that is the column name that references the primary key in another table	`DEPTNO`
9	Sequence number within foreign key	`1`
10	Update rule, that is, what happens to the foreign key when the primary key is updated.	`null`
11	Delete rule, that is, what happens to the foreign key when the primary key is deleted.	`1`
12	Foreign imported key name	`FK_DEPTNO`
13	Primary key name in referenced table	`PK_DEPT`

In the schema SCOTT there is only one foreign imported key. The table EMP contains a field, DEPTNO, that references the primary key in the DEPT table, the DEPTNO field. EMP is the referencing table and DEPT is the referenced table. DEPTNO is a foreign imported key in the EMP table. Reciprocally, the DEPTNO field in the table DEPT is an exported foreign key, as well as being the primary key.

For a description of the codes for update and delete rules, see
http://java.sun.com/products/jdk/1.2/docs/api/java/sql/package-summary.html for the DatabaseMetaData object property getImportedKeys.

See Also
crossreference, dmd, exportedkeys, get, primarykeys

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