Each EDW 3NF table column has a set of associated properties. The definition of each property is described below:
- If the Column name or Data type is changed for a column then the metadata will differ from the table as recorded in the database.
- Use the Validate > Validate Table Create Status menu option or the right-click menu to compare the metadata to the table in the database.
- A right-click menu option of Alter table is available when positioned on the table name after the validate has been completed. This option will alter the database table to match the metadata definition.
Sample EDW 3NF Properties screen:
General
| Field | Description |
|---|
| Table Name | Database-compliant name of the table that contains the column. [Read-only]. |
| Column Name | Database-compliant name of the column. Typically column-naming standards exclude the use of spaces etc. A good practice is to only use alphanumerics and the underscore character. Changing this field alters the table's definition.| Note: |
|---|
| A case conversion button on the right converts the text between different cases: UPPER CASE, Capitalized Case, and lower case. The mode cycles to the next case in the sequence each conversion. |
|
| Business Display Name / Column Title | Name that the business uses to refer to the column, which is included in the RED-generated documentation and can be used in the end user layer of other tools. [Does NOT affect the physical database table]. As such it is a free form entry and any characters are valid.| Note |
|---|
| A case conversion button on the right converts the text between different cases: UPPER CASE, Capitalized Case and lower case. The mode cycles to the next case in the sequence each conversion. |
|
| Column Description | This field contains the description for the column. It may be a description from a business user's point of view. This field might additionally contain information on where and how the column was acquired. For example if the column is sourced from multiple tables or is a composite or derived column then this definition would normally describe the process used to populate the column. This field is used in the documentation and is available via the view ws_admin_v_dim_col. This field is also stored as a comment against the column in the database. |
Physical Definition
| Field | Description |
|---|
| Column Order | Numeric value that controls the relative order of columns in the database create statement. The lowest numbered column will appear first in the table. Although this affects the physical table definition no action will be taken unless the table is re-created in the database. The columns can be re-numbered based on the existing order by choosing the Respace Order Number pop-up menu option when positioned over any column in the table. This action will number the columns in increments of 10 starting at 10. In addition to a simple change of the order field, the column order can be changed by first displaying the columns in the middle pane and then using drag and drop to move the columns around. This drag and drop process will automatically renumber the columns as required |
| Data Type | Database-compliant data type that must be valid for the target database. For SQL Server common types are integer, numeric, varchar() and datetime. See the database documentation for a description of the data types available. Changing this field alters the table's definition. |
| Null Values Allowed | Determines whether the table column can hold NULL values or whether a value is always mandatory. |
| Default Value | Initial value that is assigned to the column when a row is inserted into the table but no value is specified for the column. |
| Field | Description |
|---|
| Format | Optional format mask that can be used in end-user tools. [Does NOT affect the physical database table]. As such it is a free-form entry and any characters are valid. Typically format masks are only used on numeric fields. Example: #,###0.00. It is not worth the effort of populating this field unless it can be utilized by the end user tools in use. |
| Numeric | Indicates whether the table column holds values that are numeric. This is normally only relevant for fact tables. It does not affect the physical table definition but rather provides input to the view ws_admin_v_dim_col which can be used to assist in the population of an end user tool's end user layer. The use of this field is not relevant unless it can be utilized by the end-user tools. |
| Additive | Indicates whether the table column holds values that are additive. This implies that the column can be summed when performing data grouping in a query. This is normally only relevant for fact tables. It does not affect the physical table definition, but rather provides input to the view ws_admin_v_dim_col which can be used to assist in the population of an end user tool's end user layer. The use of this field is not relevant unless it can be utilized by the end user tools. |
| Attribute | Indicates whether the table column holds values that are descriptive, and/or are used for grouping/summing. An attribute is defined as a non-factual column. For example we may have an order number or an invoice number stored in the fact table. Such columns are considered attributes, rather than facts. This checkbox is therefore normally only relevant for fact tables. This checkbox does not affect the physical table definition, but rather provides input to the view ws_admin_v_dim_col which can be used to assist in the population of an end user tools end user layer. The use of this field is not relevant unless it can be utilized by the end-user tools. |
| End User Layer Display | Indicates whether the table column is available/visible to end users. If set the documentation will include the column in the glossary and in the user documentation. It is also used to decide what columns appear in the view ws_admin_v_dim_col. Typically columns such as the artificial key would not be enabled for end-user display |
| Business Key | Indicates whether the column is part of the BUSINESS key, which is defined during the update procedure build. [Normally maintained automatically]. Multiple columns can form the primary business key. |
| Artificial Key | Indicates whether the column is the artificial key. Only one artificial key is supported. This indicator is set by WhereScape RED during the initial drag-and-drop creation of a table, and should not normally be altered. |
| Key Type | Key type that is assigned and used when generating the table's update procedure and indexes. [Normally maintained automatically]. It can be altered here, but this should only be done if the consequences are fully understood and tested.
The supported values are:| Key type | Meaning |
|---|
| 0 | The artificial key. Set when the key is added during drag and drop table generation. | | 1 | Component of all business keys. Indicates that this column is used as part of any business key. | | A | Indicates that the column is part of the primary business key. Set whenever a business key is defined as part of an update procedure generation. | | B-Z | Indicates that the column is part of a secondary business key. Only used during index generation and not normally set. |
|
Source Details
| Field | Description |
|---|
| Source Table | Identifies the source table where the column's data comes from. This source table is normally a load table within the data warehouse. If the column was sourced from multiple tables, then the normal practice is to record one of the tables in this field and a comment listing all of the other tables in the Source Strategy field. This field is used when generating a procedure to update the EDW 3NF table. It is also used in the trackback diagrams and the documentation. |
| Source Column | Identifies the source column where the column's data comes from. Such a column is normally a load table column, which in turn may have been a transformation or the combination of multiple columns. For previous value-managed columns, the source column is the column in the table whose previous value is being recorded. |
| Source Data Type | Identifies the source column's data type. [Read-only]. |
| Transformation | Refer to EDW 3NF Table Column Transformations. [Read-only]. |
| Join | Indicates whether the table column is used in a table join. [Normally maintained automatically but can be optionally changed to override the default join logic used in the generated update procedure]. The Source Table and Source Column fields will provide the other EDW 3NF table's side of the join. The options for this field are: False, True, Manual, and Pre-Join.- Setting this field to Manual changes the way the dimension table is looked up during the update procedure build. It allows you to join the dimension manually in the Source Join wizard (used to build the 'Where' clause).
- Setting this field to Pre Join activates the Pre Join Source Table field and allows you to select a table from the drop-down list.
|
| Pre Join Source Table | Indicates the table from which the pre-joined column was sourced. When the Join option is set to False, this field becomes inactive. When the Join option is set to True or Manual, this field is set to the current table name. When the Join option is set to Pre Join, then you can select the required table from the drop-down list. |