Relation:Tutorial 3
Tables
In Belle Nuit Relation, relations are tables, tuples rows and columns properties.
Row and column are not significant and each row is unique.
Tables always have a column header
You can create a table right in Relation. The table below was written with the code you can see on the right of this page.
| id | title | country |
|---|---|---|
| 1001 | Ma vie de Courgette | CH |
| 1002 | Elle | FR |
| 1003 | Toni Erdmann | DE |
| 1004 | Above and Below | CH |
In the first line relation you create a new relation and define the columns. The columns must be Valid names, eg alphanumeric.
The following insert lines add the rows. In Relation, you write numbers directly and text should be in quotes. However, the columns are not typed. If id in this example is number or text depends on how you use it in expressions.
Finally, print writes the current relation to the note book.
Normally, you will not write data directly into Relation, but from files. For the rest of the tutorial we will use a comma-separated-values file (CSV) films.csv. You can export CSV from Excel, Numbers and many other application, even write manually.
| film | director | year |
|---|---|---|
| A bout de souffle | Godard | 1960 |
| Tirez sur le pianiste | Truffaut | 1960 |
| Cléo de 5 à 7 | Varda | 1962 |
| Jules et Jim | Truffaut | 1962 |
| Pierrot le fou | Godard | 1965 |
| Week-End | Godard | 1967 |
| Die verlorene Ehre der Katharina Blum | von Trotta | 1975 |
| Der starke Ferdinand | Kluge | 1976 |
| Sans toi ni loi | Varda | 1985 |
Every line in the Relation program begins with an instruction. We now have used relation, insert, print and read.
The instructions are executed line by line and may create relations and put it on the stack, manipulate the current relation on top of the stack or combine multiple relations on the stack.
For each instruction, there might options. The relation instruction needs a list of columns, the insert instruction data and the read instruction a filnename.
You may note that there is only a filename and no path. How does Relation know where to look for the file? The file must be in the same folder as the program you write. Relation works in a Sandbox.
Go to Tutorial 4
' ===Tables===
' In Belle Nuit Relation, relations are tables, tuples rows and columns properties.
' Row and column are not significant and each row is unique.
' Tables always have a column header
' You can create a table right in Relation. The table below was written with the code you can see on the right of this page.
relation id, title, country
insert 1001 , "Ma vie de Courgette" , "CH"
insert 1002 , "Elle" , "FR"
insert 1003 , "Toni Erdmann" , "DE"
insert 1004 , "Above and Below" , "CH"
' In the first line '''relation''' you create a new relation and define the columns. The columns must be [[valid names]], eg alphanumeric.
' The following '''insert''' lines add the rows. In Relation, you write '''numbers''' directly and '''text''' should be in quotes. However, the columns are not typed. If ''id'' in this example is number or text depends on how you use it in expressions.
' Finally, '''print''' writes the current relation to the note book.
' Normally, you will not write data directly into Relation, but from files. For the rest of the tutorial we will use a comma-separated-values file (CSV) [[Media:films.csv]]. You can export CSV from Excel, Numbers and many other application, even write manually.
read "films.csv"
' Every line in the Relation program begins with an instruction. We now have used '''[[relation]]''', '''[[insert]]''', '''[[print]]''' and '''[[read]]'''.
' The instructions are executed line by line and may create relations and put it on the stack, manipulate the current relation on top of the stack or combine multiple relations on the stack.
' For each instruction, there might options. The '''relation''' instruction needs a list of columns, the '''insert''' instruction data and the read instruction a filnename.
' You may note that there is only a filename and no path. How does Relation know where to look for the file? The file must be in the same folder as the program you write. Relation works in a [[sandbox]].
' Go to [[Tutorial 4]]