# Study on Effective Temporal Data Retrieval Leveraging Complex Indexed Architecture
## 5 Data Retrieval
### Proposed Select Statement Definition
AS-IS option looks at the data structure as it is currently expressed with the reflection on the validity of the given state of the object. AS-WILL-BE is specific and can be associated only with the future valid state. Model transformation by the constraint evolution can be defined sooner before its real usability. If the AS-WILL-BE option is used, future valid states are reflected by the model valid in the future. If there is no model for the specified time frame, either exception is raised or the AS-IS model is used. The behavior depends on the future_strictness parameter, which can hold either TRUE value (forcing the system to cover only future valid data model) or FALSE, which replaces undefined future data model by the current definition (AS-IS). Note, that the FALSE option is used, by default. **Model_reflection((AS-WAS, AS-IS, AS_WILL-BE [(time_frame)])**  
* **Consistency_model**  
During the data monitoring and evaluation, the efficiency of the processing must be taken into emphasis, as well. Mostly in highly dynamic systems, input values can be delayed in a temporal manner, which can impact the complexity, decision making, and overall reliability reflection of the system. In general, three temporal timestamp signatures are used for the evaluation. Sent_time reflects the time of data production, either by the different system, sensor layer, etc. Received_time is a specification of the timestamp signature when the data were placed in the input queue for processing. The time costs of the data transfer are then reported as the difference between the Received_time and Sent_time. Finally, Processed_time delimits the time of the data processing directly by the database system. The difference between the Processed_time and Sent_time is crucial for the database system itself, whereas it reflects the adequacy of architecture, approaches, and robustness of database processing. The aim is to minimize such value so that the received data are ideally processed immediately. The time difference is important for efficiency, reliability with emphasis on the frequency of changes. Optional time aspect definition can be covered by the signature of the transaction approval, which is relevant mostly in the systems containing long transactions. Just after reaching transaction commit (approval), processed data are widespread and can be used by any other session, respectively transaction. The time point of the transaction approval is denoted by the Transaction_approve_time. The specification is based on adding additional flags for each row in the data output set reflecting the consistency_model and processing or transferring delays. * **Epsilon_definition--time/position precision placement** For monitoring developments and changes over time, it is possible to define rules that affect the size of the result set. Epsilon_definition is a determination of how insignificant changes can be filtered out, especially in sensory data. Each monitored temporal attribute can have a defined minimum value of the extent of a significant change--the value of Epsilon (\(\epsilon\)). If the difference between two consecutive values of a given attribute is less than the value of the parameter defined for the corresponding temporal attribute, then this change will not appear in the resulting set returned by the Select statement. If this clause is not user-defined, the default value of the minimum change (\(\epsilon=0\)) will be used, in which case any change will be processed. To use this extension functionality, it is necessary to define a function that will map the values of non-numeric data types to numeric so that changes can be quantified. It is, therefore, necessary to define a mapping function for each data type (or use an implicit one), the input parameter of which is the value of the respective data type, the result is a numerical value (integer, float, longit,...). It can be managed on the temporal and spatial spheres. Note, that not only direct predecessor can be evaluated, the defined window can be used, as well.