# Internal database schema

The following tables are used internally by DeepDive. There can *not* be tables
with the same name in the database:

```
List of relations
Schema | Name | Type
--------+----------------------------------------------+----------
public | dd_graph_variables_holdout | table
public | dd_graph_variables_observation | table
public | dd_graph_weights | table
public | dd_inference_result_variables | table
public | dd_inference_result_weights | table
public | dd_inference_result_weights_mapping | view
public | dd_factors_[RULE_NAME] | table
public | dd_weights_[RULE_NAME] | table
public | [TABLE]_[VARIABLE]_inference | view
public | [TABLE]_[VARIABLE]_calibration | view
public | dd_categories_[TABLE] | view
```

where `[RULE_NAME]`

is the name of an inference rule, `[TABLE]`

is the
name of a table that contains variables, and `[VARIABLE]`

is the name
of a variable in the corresponding table.

Description of each schema:

`dd_graph_variables_holdout`

: a table that contains all variable ids that are used for holdout. Can be used for custom holdout by a holdout query.`dd_graph_variables_observation`

: a table that contains all variable ids that are evidence that will not be fitted during learning. An usage example of this table can be found here.`dd_graph_weights`

: a table that contains all the materialized weights.`dd_inference_result_variables`

: a table that contains the inference results (expectation) for all query variables.`dd_inference_result_weights`

: a table that shows factor weight ids and learned weight values.`dd_inference_result_weights_mapping`

: a view that maps all distinct factor weights to their description and their learned values. It is a commonly used view that shows the learned weight value of a factor as well as the number of occurences of a factor.`dd_factors_[RULE_NAME]`

: a table that is defined by the input query of an inference rule. You can use it as a feature table in BrainDump.`dd_weight_[RULE_NAME]`

: a table that stores initial weights for factors, used internally.`[TABLE]_[VARIABLE]_inference`

: a view that maps variables with their inference results. It is commonly used for error analysis.`[TABLE]_[VARIABLE]_calibration`

: a view that has calibration statistics of a variable. Used in generating calibration plots.`dd_categories_[TABLE]`

: a view that records the cardinality series of given variable. For example if the domain of a variable is {1,2,3} the cardinality is 3.