TableDelete Class Reference

Operation to delete data from a table. More...

Methods
TableDelete	delete ()
	Initializes the deletion operation. More...
TableDelete	where (str expression)
	Sets the search condition to filter the records to be deleted from the Table. More...
TableDelete	order_by (list sortCriteria)
	Sets the order in which the records will be deleted. More...
TableDelete	limit (int numberOfRows)
	Sets the maximum number of rows to be deleted by the operation. More...
TableDelete	bind (str name, Value value)
	Binds a value to a specific placeholder used on this operation. More...
Result	execute ()
	Executes the delete operation with all the configured options. More...

Detailed Description

Operation to delete data from a table.

Handler for Delete operation on Tables.

Member Function Documentation

delete()

TableDelete delete

(

)

Initializes the deletion operation.

Returns

This TableDelete object.

This function is called automatically when Table.delete() is called.

The actual deletion of the records will occur only when the execute() method is called.

Method Chaining

After this function invocation, the following functions can be invoked:

• where(str expression)
• order_by(list sortCriteria), order_by(str sortCriterion[, str sortCriterion, ...])
• limit(int numberOfRows)
• execute()

See also

Usage examples at execute().

where()

TableDelete where

(

str

expression

)

Sets the search condition to filter the records to be deleted from the Table.

Parameters

expression

A condition to filter the records to be deleted.

Returns

This TableDelete object.

If used, only those rows satisfying the expression will be deleted

The expression supports Parameter Binding.

Method Chaining

This function can be invoked only once after:

• delete()

After this function invocation, the following functions can be invoked:

• order_by(list sortCriteria), order_by(str sortCriterion[, str sortCriterion, ...])
• limit(int numberOfRows)
• bind(str name, Value value)
• execute()

See also

Usage examples at execute().

order_by()

TableDelete order_by

(

list

sortCriteria

)

Sets the order in which the records will be deleted.

Returns

This TableDelete object.

If used, the TableDelete operation will delete the records in the order established by the sort criteria.

Every defined sort criterion follows the format:

name [ ASC | DESC ]

ASC is used by default if the sort order is not specified.

Method Chaining

This function can be invoked only once after:

• delete()
• where(str expression) After this function invocation, the following functions can be invoked:
• limit(int numberOfRows)
• bind(str name, Value value)
• execute()

See also

Usage examples at execute().

limit()

TableDelete limit

(

int

numberOfRows

)

Sets the maximum number of rows to be deleted by the operation.

Parameters

numberOfRows

The maximum number of rows to be deleted.

Returns

This TableDelete object.

If used, the operation will delete only numberOfRows rows.

Method Chaining

This function can be invoked only once after:

• delete()
• where(str expression)
• order_by(list sortCriteria), order_by(str sortCriterion[, str sortCriterion, ...]) This function can be called every time the statement is executed.

After this function invocation, the following functions can be invoked:

• bind(str name, Value value)
• execute()

See also

Usage examples at execute().

bind()

TableDelete bind	(	str	name,
		Value	value
	)

Binds a value to a specific placeholder used on this operation.

Parameters

name	The name of the placeholder to which the value will be bound.
value	The value to be bound on the placeholder.

Returns

This TableDelete object.

Binds the given value to the placeholder with the specified name.

An error will be raised if the placeholder indicated by name does not exist.

This function must be called once for each used placeholder or an error will be raised when the execute method is called.

Method Chaining

This function can be invoked multiple times right before calling execute().

After this function invocation, the following functions can be invoked:

• bind(str name, Value value)
• execute()

See also

Usage examples at execute().

execute()

Result execute

(

)

Executes the delete operation with all the configured options.

Returns

A Result object.

Method Chaining

This function can be invoked after any other function on this class.

Examples

Deleting records with a condition

result = table.delete().where('age = 15').execute()
print('Affected Rows:', result.affected_items_count, '\n')
 
records = table.select().execute().fetch_all()
print('Records Left:', len(records), '\n')

Deleting records with a condition and parameter binding

result = table.delete().where('gender = :heorshe').limit(2).bind('heorshe', 'male').execute()
print('Affected Rows:', result.affected_items_count, '\n')
 
records = table.select().execute().fetch_all()
print('Records Left:', len(records), '\n')

Deleting all records using a view

view = schema.get_table('view1')
result = view.delete().execute()
print('Affected Rows:', result.affected_items_count, '\n')
 
# Deletion is of course reflected on the target table
records = table.select().execute().fetch_all()
print('Records Left:', len(records), '\n')

Deleting records with a limit

result = table.delete().limit(2).execute()
print('Affected Rows:', result.affected_items_count, '\n')
 
records = table.select().execute().fetch_all()
print('Records Left:', len(records), '\n')