# dm.selectors.row package

## Submodules

## dm.selectors.row.AbstractTableRowSelector module

Abstract class for one value selector.

Selector can select value based on given time from a table.

class `dm.selectors.row.AbstractTableRowSelector.``AbstractRowSelector`(con, table_name)

  Bases: `dm.selectors.AbstractSelector.AbstractSelector`

  abstract `row`(column_name, time)

    It selects one row from source.

    Parameters

      - column_name – name of column that contains required values

      - time – timestamp of required data

    Returns

      data from the column in given time

## dm.selectors.row.CachedDiffRowWithIntervalSelector module

Cached row selector for selection of differences of values.

class `dm.selectors.row.CachedDiffRowWithIntervalSelector.``CachedDiffRowWithIntervalSelector`(con, table_name, start, end)

  Bases: `dm.selectors.row.CachedRowWithIntervalSelector.CachedRowWithIntervalSelector`

  `row`(column_name, time)

    It selects one row from cache.

    It also performs difference between two obtained values.

    Parameters

      - column_name – name of column that contains required values

      - time – timestamp of required data

    Returns

      data from the column in given time

## dm.selectors.row.CachedRowWithIntervalSelector module

Cached interval selector from database.

Selector can select given intervals of values from a given table and selected rows are stored into cache.

class `dm.selectors.row.CachedRowWithIntervalSelector.``CachedRowWithIntervalSelector`(con, table_name, start, end)

  Bases: `dm.selectors.row.SimpleCachedRowSelector.SimpleCachedRowSelector`

  `row`(column_name, time)

    It selects one row from cache.

    If the method is called for the first time, cache will be initialized.

    Parameters

      - column_name – name of column that contains required values

      - time – timestamp of required data

    Returns

      data from the column in given time

## dm.selectors.row.LinearSimpleCachedRowSelector module

## dm.selectors.row.SimpleCachedRowSelector module

Cached selector for one value from database.

Selector can select value based on given time from a table in database and selected values are stored in cache.

class `dm.selectors.row.SimpleCachedRowSelector.``SimpleCachedRowSelector`(con, table_name)

  Bases: `dm.selectors.row.AbstractTableRowSelector.AbstractRowSelector`

  `row`(column_name, time)

    It selects one row from cache or database.

    If the method is called for the first time, cache will be initialized. The second call of the method returns loaded data stored in cache.

    Parameters

      - column_name – name of column that contains required values

      - time – timestamp of required data

    Returns

      data from the column in given time

## dm.selectors.row.SimpleRowSelector module

## Module contents