Oracle - Datamart

Applies to
Platform: Oracle
Architecture: Data Mart

Oracle - Datamart generates a Mart layer for an Oracle database from the objects of linked projects, as SQL*Plus scripts with PL/SQL loader packages. Select it in Project Settings, where Generator Configuration shows Oracle DataMart, when your data mart runs on Oracle. This article lists what the configuration supports and where it differs from Microsoft SQL Server - Datamart.

Scope and output

Platform: Oracle. The configuration is available since Generator 2.0.
Layers: Mart, and the layers of the imported linked projects. Dataflow Modeling shows the imported objects in the Linked column in Silver and the Mart layer as the Datamart column in Gold. See Understand the Layering concept.
Output: a SQL*Plus script for the Mart layer, PL/SQL loader packages, the load control scripts and the PowerShell 7 scripts that deploy and load, described in Oracle - Artifacts.

Prerequisites

One Oracle user for the Mart layer and one for load control (with Native Load Control). The user name is also the schema name of the layer.
PowerShell 7 and SQL*Plus on the machine that deploys.
The privileges listed in Oracle - Target environment.

The placeholders for the users, schemas and connections are listed in Oracle - Placeholder values.

Sources and linked projects

The configuration reads only model objects of linked projects, for example of a Data Vault or Data Store project. It has no discovery of its own and does not offer Database Links for Source Systems. Import a linked project before you model the Mart layer. You can also export this project as a linked project.

Create GRANTs for Imported Objects decides whether the deployment grants the imported objects to the Mart user. When it is on, the deployment also connects as the users of the linked layers.

Supported model objects

Capabilities and limitations

Names: generated names are unquoted and in capitals. Characters other than letters, digits, _, $ and # become _, and names are cut to 128 characters.
Keys: primary keys are created with RELY and a unique index, and business keys get a unique constraint. Foreign Key Mode on Mart Facts offers None, Create Disabled and Create Enforced; the default is Create Disabled.
Indexes: the deployment creates an index on the referencing columns of each relationship, unless the primary key or a unique key has the same columns. On Mart Facts it is a bitmap index, otherwise a B-tree index. Index management offers B-Tree Index and Bitmap Index and the option Create as local Index.
Table storage: the partition, compression, tablespace and statistics properties of a model object are described in Partition Clause and table storage (Model Object).
Wide objects: Hash Group Size splits the row hash of Mart Dimensions into groups.
Identity values: the surrogate keys of Mart Dimensions and identity columns such as BG_ID are NUMBER GENERATED BY DEFAULT AS IDENTITY.
Grants: the Mart layer grants EXECUTE on its loader packages to the load-control user.
Loading: LoadControl Options offers Native Load Control and Airflow.
Data types: the platform data types CHAR(CHAR), CHAR(BYTE), VARCHAR2(CHAR) and VARCHAR2(BYTE) write the length semantics, for example VARCHAR2(100 CHAR). CHAR and VARCHAR2 write none, so the database setting NLS_LENGTH_SEMANTICS applies. TIMESTAMP WITH TIME ZONE with precision 3 becomes TIMESTAMP(3) WITH TIME ZONE.
Data type validation: a length, precision or scale that does not fit the Oracle data type gets a warning, see Invalid data type configuration (Business Rule). The generator writes the configured value: VARCHAR2(5000) fails with ORA-00910 at deployment on a database with MAX_STRING_SIZE = STANDARD.

Project properties

Project Settings shows these properties of the configuration, with their defaults:

Hash Algorithm: SHA1; also MD5, SHA256, SHA384 and SHA512

With SHA256, SHA384 or SHA512, the hash Default Terms stay RAW(20). Set their data type to the result length of the algorithm, see Hash Algorithm.

Hash Casing: None; also Upper and Lower
Hash Concatenation Separator: _
Hash Null Placeholder: _NULL_
Hash Trim: off
Begin of Universe: 19000101
End of Universe: 99991231
Persist Validity: off
Create Result Views: on
Target Object Comment Type: None
Artifact Output Mode: Layer Composites
Deployment Options: Generate Drop Table Statements
Configure LoadControl: on
Deploy LoadControl: on
LoadControl Options: Native Load Control; also Airflow
Create GRANTs for Imported Objects: on

Platform differences

The table compares the configuration with Microsoft SQL Server - Datamart of the same release:

Item	Oracle	Microsoft SQL Server
Timestamp Default Terms	`TIMESTAMP`	`datetimeoffset`
Hash Default Terms	`RAW(20)`	`binary(20)`
Text Default Terms	`VARCHAR2`	`nvarchar`
Number Default Terms	`NUMBER`	`int` or `bigint`
Flag Default Terms	`NUMBER(1, 0)`	`bit`
Hash Algorithm values besides `SHA1` and `MD5`	`SHA256`, `SHA384`, `SHA512`	`SHA2_256`
Index types	B-tree, bitmap	rowstore, columnstore

Create GRANTs for Imported Objects, Hash Group Size, Create as local Index and the table storage properties exist only on Oracle. Included Columns of an index exists only on Microsoft SQL Server.

These Default Terms belong to each group; text Default Terms have the same lengths on both platforms:

Timestamps: BG_LoadTimestamp, BG_ValidFromTimestamp, BG_ValidToTimestamp, BG_UpdateTimestamp, BG_EffectiveTimestamp
Row hashes: BG_RowHash, BG_RowHashScd1, BG_RowHashScd2
Text: BG_SourceSystem, BG_DataflowName, BG_DataflowSetName, BG_ErrorDescription, BG_IncrementLoadStatus
Numbers: BG_ID, BG_ErrorCount, BG_DataQuality_ID, BG_MartDimension_Identity, BG_MartFact_ForeignKey_Identity
Flags: BG_IsDeleted

Example

A Mart Dimension common_pos with the business key term POS_ID generates this table. Its surrogate key COMMON_POS_SK is an identity column. In the excerpt, <mart schema> stands for the placeholder of the Mart schema, and short lines are joined:

CREATE TABLE <mart schema>.DM_MD_COMMON_POS (
     BG_SOURCESYSTEM VARCHAR2(255)
    ,BG_LOADTIMESTAMP TIMESTAMP NOT NULL
    ,COMMON_POS_SK NUMBER GENERATED BY DEFAULT AS IDENTITY NOT NULL
    ,POS_ID NUMBER NOT NULL
    ,CASHBOX_NO NUMBER NOT NULL
    ,BRANCH_ID NUMBER NOT NULL
    ,HUB_HK RAW(20) NOT NULL
    ,BG_ROWHASHSCD1 RAW(20) NOT NULL
)
;
ALTER TABLE <mart schema>.DM_MD_COMMON_POS
ADD CONSTRAINT DM_MD_COMMON_POS_PK PRIMARY KEY (COMMON_POS_SK)
RELY
USING INDEX (
    CREATE UNIQUE INDEX <mart schema>.DM_MD_COMMON_POS_PK
    ON <mart schema>.DM_MD_COMMON_POS (COMMON_POS_SK)
);
ALTER TABLE <mart schema>.DM_MD_COMMON_POS
ADD CONSTRAINT DM_MD_COMMON_POS_UK UNIQUE (POS_ID)
USING INDEX (
    CREATE UNIQUE INDEX <mart schema>.DM_MD_COMMON_POS_UK
    ON <mart schema>.DM_MD_COMMON_POS (POS_ID)
);

On Microsoft SQL Server, BG_SOURCESYSTEM and BG_LOADTIMESTAMP get the types nvarchar(255) and datetimeoffset.

Release differences

Project Settings shows the Generator Version of your project.

Generator 2.0: first release of the configuration.
Generator 2.2: Mart Out; the project properties Persist Validity, Create Result Views, Hash Casing, Hash Concatenation Separator, Hash Null Placeholder and Hash Trim; the model object property Increment Management Type on Mart Facts; the platform data types with length semantics and the data type validation; the replacement of characters in generated names. Up to Generator 2.0.1, precision 3 was written as TIMESTAMP(3 WITH TIME ZONE).
Generator 2.3: the model object properties Hash Group Size and Custom Singleton Values.
Fixes for Oracle are listed in Generators Release - 2.3.0, Generators Release - 2.4.0 and Generators Release - 2.4.1.