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RDBMS Deployment Descriptors
weblogic-cmp-rdbms-jar.xml deployment descriptors
This section describes the 6.1 WebLogic Server-specific XML elements found in weblogic600-cmp-rdbms-jar.xml that are used to define the deployment descriptors in the WebLogic Server EJB container. These elements map to fields, of approximately the same name, in the WebLogic Server Administration Console Use these deployment descriptors for 2.0 EJBs.
automatic-key-generation
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
Optional. |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The automatic-key-generation element specifies the use of the Sequence/Key Generation feature.
cmp-field
Function
This name specifies the mapped field in the bean instance which should be populated with information from the database.
cmr-field
Function
The cmr-field element specifies the name of a cmr-field.
column-map
Function
This element represents the mapping of a foreign key column in one table in the database to a corresponding primary key. The two columns may or may not be in the same table. The tables to which the column belong are implicit from the context in which the column-map element appears in the deployment descriptor.
create-default-dbms-table
Function
The create-default-dbms-table element turns on or off a feature that automatically creates a default table based on the descriptions in the deployment files and the bean class. When set to False, this feature is turned off and table will not automatically be generated. When set to True, this feature is turned on and the table is automatically created. If TABLE CREATION fails, a Table Not Found error is thrown and the table must be created by hand.
data-source-name
Function
The data-source-name that specifies the JDBC data source name to be used for all database connectivity for this bean.
db-cascade-delete
Function
The db-cascade-delete element specifies whether the database cascade feature is turned on. If this element is not specified, WebLogic Server
dbms-column
Function
The name of the database column to which the field should be mapped.
dbms-column-type
Range of values: |
Valid name |
Default value: |
n/a |
Requirements: |
Available for use with Oracle database only. |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The dbms-column-type element maps the current field to a Blob or Clob in an Oracle database. This element can be either OracleBlob or OracleCLob.
delay-database-insert-until
Function
The delay-database-insert-until element specifies the precise time when a new bean that uses RDBMS CMP is inserted into the database.
It is advisable to delay the database insert until after the ejbPostCreate method modifies the persistent fields of the bean. This can yield better performance by avoiding an unnecessary store operation.
For maximum flexibility, you should avoid creating related beans in your ejbPostCreate method. This may make delaying the database insert impossible if database constraints prevent related beans from referring to a bean that has not yet been created.
ejb-name
Function
The name that specifies an EJB as defined in the ejb-cmp-rdbms.xml. This name must match the ejb-name of a cmp entity bean contained in the ejb-jar.xml.
field-group
Function
The field-group element represents a subset of the cmp and cmr-fields of a bean. Related fields in a bean can be put into groups that are faulted into memory together as a unit. A group can be associated with a finder or relationship, so that when a bean is loaded as the result of executing a finder or following a relationship, only the fields specified in the group are loaded.
A field may belong to multiple groups. In this case, the getXXX method for the field faults in the first group that contains the field.
field-map
Function
The name of the mapped field for a particular column in a database that corresponds to a cmp field in the bean instance.
foreign-key-column
Range of values: |
Valid name |
Default value: |
n/a |
Requirements: |
Must correspond to a column of a foreign key. |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The foreign-key-column element represents a column of a foreign key in the database.
generator-name
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
Optional. |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The generator-name element is used to specify the name of the generator.
For example;
generator-type
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
Optional |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The generator-type element specifies the key generation method to use. The options include:
group-name
Function
The group-name element specifies the name of a field group.
include-updates
Function
The include-updates element specifies that updates made during the current transaction must be reflected in the result of a query. If this element is set to True, the container will flush all changes made by the current transaction to disk before executing the query.
key-cache-size
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
Optional |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The key-cache-size element specifies the optional size of the primary key cache available in the automatic primary key generation feature.
key-column
Range of values: |
Valid name |
Default value: |
n/a |
Requirements: |
Must correspond to a column of a primary key. |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The key-column element represents a column of a primary key in the database.
max-elements
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
n/a |
Parent elements: |
weblogic-rdbms-bean weblogic-query |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
max-elements specifies the maximum number of elements that should be returned by a multi-valued query. This element is similar to the maxRows feature in JDBC.
method-name
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
The `*' character may not be used as a wildcard. |
Parent elements: |
weblogic-rdbms-bean query-method |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The method-name element specifies the name of a finder or ejbSelect method.
method-param
Range of values: |
Valid name |
Default value: |
n/a |
Requirements: |
n/a |
Parent elements: |
weblogic-rdbms-bean method-params |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The method-param element contains the fully qualified Java type name of a method parameter.
method-params
Range of values: |
list of valid names |
Default value: |
n/a |
Requirements: |
n/a |
Parent elements: |
weblogic-rdbms-bean query-method |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The method-params element contains an ordered list of the fully-qualified Java type names of the method parameters.
query-method
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
n/a |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The query-method element specifies the method that is associated with a weblogic-query. It also uses the same format as the ejb-jar.xml descriptor.
relation-name
Function
The relation-name element specifies the name of a relation.
relationship-role-name
Function
The relationship-role-name element specifies the name of a relationship role.
table-name
Function
The fully qualified SQL name of the table. The user defined for the data-source for this bean must have read and write privileges for this table, but does not necessarily need schema modification privileges.
weblogic-ql
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
n/a |
Parent elements: |
weblogic-rdbms-bean weblogic-query |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The weblogic-ql element specifies a query that contains a WebLogic specific extension to the ejb-ql language. You should specify queries that only use standard EJB-QL language features in the ejb-jar.xml deployment descriptor.
weblogic-query
Range of values: |
n/a |
Default value: |
n/a |
Requirements: |
n/a |
Parent elements: |
weblogic-rdbms-bean |
Deployment file: |
weblogic-cmp-rdbms-jar.xml |
Function
The weblogic-query element allows you to associate WebLogic specific attributes with a query, as necessary. For example, weblogic-query can be used to specify a query that contains a WebLogic specific extension to EJB-QL. Queries that do not take advantage of WebLogic extensions to EJB-QL should be specified in the ejb-jar.xml deployment descriptor.
Also, the weblogic-query element is used to associate a field-group with the query if the query retrieves an entity bean that should be pre-loaded into the cache by the query.
weblogic-relationship-role
Function
The weblogic-relationship-role element is used to express a mapping from a foreign key to a primary key. Only one mapping is specified for one-to-one relationships when the relationship is local. However, with a many-to-many relationship, you must specify two mappings
Multiple column mappings are specified for a single role, it the key is complex. No column-map is specified if the role is just specifying a group-name.
This section describes the 6.1 WebLogic Server-specific XML elements found in weblogic510-cmp-rdbms-jar.xml that are used to define the deployment descriptors in the WebLogic Server EJB container. These elements map to fields, of approximately the same name, in the WebLogic Server Administration Console Use these deployment descriptors for 1.1 EJBs.
RDBMS Definition elements
This section describes the RDBMS definition elements.
pool-name
pool-name specifies name of the WebLogic Server connection pool to use for this EJB's database connectivity.
schema-name
schema-name specifies the schema where the source table is located in the database. This element is required only if you want to use a schema that is not the default schema for the user defined in the EJB's connection pool.
Note: This field is case sensitive, although many SQL implementations ignore case.
table-name
table-name specifies the source table in the database. This element is required in all cases.
Note: The user defined in the EJB's connection pool must have read and write privileges to the specified table, though not necessarily schema modification privileges. This field is case sensitive, although many SQL implementations ignore case.
EJB Field-Mapping elements
This section describes the EJB field-mapping elements.
attribute-map
The attribute-map stanza links a single field in the EJB instance to a particular column in the database table. The attribute-map must have exactly one entry for each field of an EJB that uses WebLogic Server RDBMS-based persistence.
object-link
Each attribute-map entry consists of an object-link stanza, which represents a link between a column in the database and a field in the EJB instance.
bean-field
bean-field specifies the field in the EJB instance that should be populated from the database. This element is case sensitive and must precisely match the name of the field in the bean instance.
The field referenced in this tag must also have a cmp-field element defined in the ejb-jar.xml file for the bean.
dbms-column
dbms-column specifies the database column to which the EJB field is mapped. This tag is case sensitive, although many databases ignore the case.
Note: WebLogic Server does not support quoted RDBMS keywords as entries to dbms-column. For example, you cannot create an attribute map for column names such as "create" or "select" if those names are reserved in the underlying datastore.
Finder elements
This section describes the finder elements.
finder-list
The finder-list stanza defines the set of all finders that are generated to locate sets of beans.
finder-list must contain exactly one entry for each finder method defined in the home interface, except for findByPrimarykey. If an entry is not provided for findByPrimaryKey, one is generated at compilation time.
Note: If you do provide an entry for findByPrimaryKey, WebLogic Server uses that entry without validating it for correctness. In most cases, you should omit an entry for findByPrimaryKey and accept the default, generated method.
finder
The finder stanza describes a finder method defined in the home interface. The elements contained in the finder stanza enable WebLogic Server to identify which method in the home interface is being described, and to perform required database operations.
method-name
method-name defines the name of the finder method in the home interface. This tag must contain the exact name of the method.
method-params
The method-params stanza defines the list of parameters to the finder method being specified in method-name.
Note: WebLogic Server compares this list against the parameter types for the finder method in the EJB's home interface; the order and type for the parameter list must exactly match the order and type defined in the home interface.
method-param
method-param defines the fully-qualified name for the parameter's type. The type name is evaluated into a java.lang.Class object, and the resultant object must precisely match the respective parameter in the EJB's finder method.
You can specify primitive parameters using their primitive names (such as "double" or "int"). If you use a non-primitive data type in a method-param element, you must specify a fully qualified name. For example, use java.sql.Timestamp rather than Timestamp. If you do not use a qualified name, ejbc generates an error message when you compile the deployment unit.
finder-query
finder-query specifies the WebLogic Query Language (WLQL) string that is used to retrieve values from the database for this finder.
Note: Always define the text of the finder-query value using the XML CDATA attribute. Using CDATA ensures that any special characters in the WLQL string do not cause errors when the finder is compiled.
finder-expression
finder-expression specifies a Java language expression to use as a variable in the database query for this finder.
Note: Future versions of the WebLogic Server EJB container will use the EJB QL query language (as required by the EJB 2.0 specification). EJB QL does not provide support for embedded Java expressions. Therefore, to ensure easier upgrades to future EJB containers, create entity EJB finders without embedding Java expressions in WLQL.
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