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jvx:reference [2020/06/15 08:49] cduncan [DataType] |
jvx:reference [2020/06/15 08:54] cduncan [Conclusion] |
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| It is possible to add new data types by simply implementing ''%%IDataType%%''. | It is possible to add new data types by simply implementing ''%%IDataType%%''. | ||
| - | ===== DataRow ===== | + | ===== Data Row ===== |
| The data row represents a single row of data; it holds/references its own row definition and, of course, provides access to the values of the row. Accessing the data row can be done either by column index or column name, and the methods either return or accept objects. Let’s look at a simple usage example: | The data row represents a single row of data; it holds/references its own row definition and, of course, provides access to the values of the row. Accessing the data row can be done either by column index or column name, and the methods either return or accept objects. Let’s look at a simple usage example: | ||
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| dataRow.setValue("COLUMN_A", "New Value"); | dataRow.setValue("COLUMN_A", "New Value"); | ||
| </code> | </code> | ||
| - | ===== DataPage ===== | + | ===== Data Page ===== |
| - | The data page is basically a list of data rows, it also holds its own row definition, which is shared with all the contained data rows. | + | The data page is basically a list of data rows. It also holds its own row definition, which is shared with all the contained data rows. |
| - | The main usage of data pages is to allow paging in a master/detail relationship. If the master selects a different row, the detail databook selects the related data page. | + | The main usage of data pages is to allow paging in a master/detail relationship. If the master selects a different row, the detail data book selects the related data page. |
| - | ===== DataBook ===== | + | ===== Data Book ===== |
| The data book is the main model of [[https://sourceforge.net/projects/jvx/|JVx]], it provides direct access to its current data page and data row by extending from IDataRow and IDataPage. | The data book is the main model of [[https://sourceforge.net/projects/jvx/|JVx]], it provides direct access to its current data page and data row by extending from IDataRow and IDataPage. | ||
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| ===== Master/Detail ===== | ===== Master/Detail ===== | ||
| - | [[https://en.wikipedia.org/wiki/Master%E2%80%93detail_interface#Data_model|Master/detail]] is something that occurs in nearly every data model. It means simply that there is one master dataset which is referenced by one or multiple detail datasets. Or to express it in SQL: | + | [[https://en.wikipedia.org/wiki/Master%E2%80%93detail_interface#Data_model|Master/detail]] is something that occurs in nearly every data model. It simply means that there is one master data set that is referenced by one or multiple detail data sets. Or to express it in SQL: |
| <code sql> | <code sql> | ||
| Line 733: | Line 733: | ||
| left join DETAIL d on m.ID=d.MASTER_ID; | left join DETAIL d on m.ID=d.MASTER_ID; | ||
| </code> | </code> | ||
| - | We can of course express a master/detail relationship when using data books. For that we just create a ''%%ReferenceDefinition%%'' and assign it to the detail data book: | + | We can, of course, express a master/detail relationship when using data books. For that, we just create a ''%%ReferenceDefinition%%'' and assign it to the detail data book: |
| <code java> | <code java> | ||
| Line 767: | Line 767: | ||
| 8| 3 | 8| 3 | ||
| </code> | </code> | ||
| - | Now if we select the second row in the ''%%masterDataBook%%'', the ''%%detailDataBook%%'' will just contain the rows with the corresponding ''%%MASTER_ID%%'', so 3, 4 and 5. | + | Now, if we select the second row in the ''%%masterDataBook%%'', the ''%%detailDataBook%%'' will just contain the rows with the corresponding ''%%MASTER_ID%%'', so 3, 4, and 5. |
| <code> | <code> | ||
| Line 778: | Line 778: | ||
| 3 5| 2 | 3 5| 2 | ||
| </code> | </code> | ||
| - | The ''%%detailDataBook%%'' is automatically adjusted according to the selection in the ''%%masterDatabook%%''. Of course this can have an arbitrary depth, too. | + | The ''%%detailDataBook%%'' is automatically adjusted according to the selection in the ''%%masterDatabook%%''. Of course, this can have an arbitrary depth too. |
| ===== Conclusion ===== | ===== Conclusion ===== | ||
| - | The data book is the backbone of [[https://sourceforge.net/projects/jvx/|JVx]], it provides a clean and easy way to access and manipulate data. At the same time, it is flexible and can be customized to specific needs with ease. | + | The data book is the backbone of [[https://sourceforge.net/projects/jvx/|JVx]]: it provides a clean and easy way to access and manipulate data. At the same time, it is flexible and can be customized to specific needs with ease. |
| ====== Application Basics ====== | ====== Application Basics ====== | ||