gws.base.database.model

Base database model.

Source code: gws.base.database.model

Module Contents

class gws.base.database.model.Config

Bases: gws.base.model.Config

Configuration for the database model.

dbUid: str | None

UID of the database provider.

sqlFilter: str | None

SQL condition added to every query of the model.

tableName: str | None

Database table of the model.

class gws.base.database.model.Object

Bases: gws.base.model.Object, gws.DatabaseModel

Base model for a database table.

Reads features from one table with SELECT queries built from the model fields, and creates, updates and deletes table rows. Provides subclasses with the database provider, access to the table and its columns, and the SELECT builder.

build_select(mc)

Build a SELECT statement for a search.

Combines the search query in mc.search, the columns and conditions collected by the fields in mc.dbSelect and sqlFilter.

Parameters:

mc – Model context with search and dbSelect set.

Returns:

The SELECT statement, or None if the search cannot match anything.

column(column_name)

Return the SQLAlchemy Column object of a column in the model table.

Parameters:

column_name – Column name.

Returns:

The column object.

Raises:

sqlalchemy.exc.SQLAlchemyError – If the table or the column does not exist.

configure()

Configuration hook.

Called when the node is initialized. Raising an exception here aborts the creation of the node.

configure_provider()
create_feature(feature, mc)

Insert a new feature into the source.

Parameters:

  • feature – The feature.

  • mc – The model context.

Returns:

The primary key of the inserted feature.

Raises:

gws.ForbiddenError – If the user cannot create features of this model.

delete_feature(feature, mc)

Delete a feature from the source.

Parameters:

  • feature – The feature.

  • mc – The model context.

Returns:

The uid of the feature.

Raises:

gws.ForbiddenError – If the user cannot delete features of this model.

describe()

Return the description of the model source.

Returns:

The dataset description, or None if the source cannot be described.

fetch_features(select)

Run a SELECT statement and create a feature for each row.

The row values become the attributes of the feature record.

Parameters:

select – SELECT statement.

Returns:

A list of features.

find_features(search, mc)

Find features matching a search query.

Parameters:

  • search – The search query.

  • mc – The model context.

Returns:

The features found.

init_feature(feature, mc)

Initialize a new feature with initial field values.

Parameters:

  • feature – The new feature.

  • mc – The model context.

Raises:

gws.ForbiddenError – If the user cannot create features of this model.

table()

Return the SQLAlchemy Table object of the model table.

Returns:

The table object.

Raises:

sqlalchemy.exc.SQLAlchemyError – If the table does not exist.

uid_column()

Return the SQLAlchemy Column object of the primary key column.

Returns:

The column object for uidName.

Raises:

gws.Error – If the model has no primary key or the key column does not exist.

uid_equals(uid)

Return a condition that matches features by uid.

The values are bound with the type of the primary key column, so that string uids can be compared with columns of other types.

Parameters:

uid – A feature uid, or an iterable of uids.

Returns:

An = condition for a single uid, an IN condition for an iterable.

Raises:

gws.Error – If the model has no primary key or the key column does not exist.

update_feature(feature, mc)

Update an existing feature in the source.

Parameters:

  • feature – The feature.

  • mc – The model context.

Returns:

The uid of the feature.

Raises:

gws.ForbiddenError – If the user cannot write to this model.

class gws.base.database.model.Props

Bases: gws.base.model.Props