# Introduction

The {{dataserver}} module is the spine of the {{uranie}} platform as it is where the data are stored, the 
attributes (name given to the variable in {{uranie}}) are gathered and important basic mathematical 
operations are performed. Objects and methods will indeed need a {{tds}} to retrieve, process and 
transmit the results of their own operations.

Since it is used by all other technical libraries ({{Sampl}}, {{Launch}}, ...), this library is the 
core library of Uranie (as shown in {numref}`fig_fonctionnal_module_orga`). The already discussed 
{{tds}} contains two main objects (has shown in {numref}`dataserver_DiagramTAttribute`):

- the **header**: represented in {{uranie}} by the object {{tdsp}}. Different information related to 
the variables (called in "attributes" in {{uranie}} language and represented by {{tattr}} objects) 
are specified in [](#dataserver_attribute).

- the **data matrix**: represented by the object {{tdsn}} (class derived from the {{root}} class 
`TTree`). For an advanced use of this object, the reader can refer to chapter XII "Trees {{root}}" 
in {{root}}'s user manual.

{{
    "```{" "figure" "} " + parent_dir +
        "/usermanual/dataserver/figures/DiagramTAttribute.png\n"
    ":align: center\n"
    ":name: dataserver_DiagramTAttribute\n"
    + figure_scale + "\n"
    "\n"
    "Diagram of the class " + tds + "\n"
    "```"
}}

The chapter presentation will be articulated as follows. First of all, the way variable are handled 
will be introduced in [](#dataserver_attribute). This is a needed step, as all {{tds}} have to be 
filled with attributes for being able to move along. The creation of a {{tds}} (with many 
construction, from {{ascii}} to {{root}} files) is discussed in [](#dataserver_data) before 
discussing the basic statistical treatment (in [](#dataserver_statistics)) and the dedicated 
visualisation tool (in [](#dataserver_vizualisation)).

`````{tip}
An important point to know for the use of {{uranie}}: all options are not case sensitive. Actually, 
the treatment of these options is taken anyway as lowercase. The following instructions are 
equivalent:

````{only} cpp
```cpp
tdsGeyser->draw("x1","","Nclass=Sturges");
tdsGeyser->draw("x2","","nclass=Sturges");
tdsGeyser->draw("x2","","nclass=sturges");
tdsGeyser->draw("x2","","NCLASS=STURGES");
```
````

````{only} py
```python
tdsGeyser.draw("x1","","Nclass=Sturges")
tdsGeyser.draw("x2","","nclass=Sturges")
tdsGeyser.draw("x2","","nclass=sturges")
tdsGeyser.draw("x2","","NCLASS=STURGES")
```
````
`````