gnue.common Public API - GNU Enterprise

Package gnue :: Package common :: Package datasources :: Module GConditions

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Module gnue.common.datasources.GConditions

Classes for the condition object tree.

Classes
`GBinaryConditionElement`	Abstract base class for all binary condition elements.
`GCadd`	Numeric addition.
`GCand`	Logical AND.
`GCbetween`	Test for SQL BETWEEN.
`GCConst`	Constant value of a specific type.
`GCdiv`	Numeric division.
`GCeq`	Test for equality.
`GCexist`	Test if a record fulfilling a given condition exists in another table.
`GCField`	Field value from a database table.
`GCge`	Test for greater or equal.
`GCgt`	Test for greater than.
`GCle`	Test for lower or equal.
`GClike`	Test for SQL LIKE.
`GClower`	String conversion to lowercase.
`GClt`	Test for lower than.
`GCmul`	Numeric multiplication.
`GCne`	Test for inequality.
`GCnegate`	Numeric negation.
`GCnot`	Logical NOT.
`GCnotbetween`	Test for SQL NOT BETWEEN.
`GCnotlike`	Test for SQL NOT LIKE.
`GCnotnull`	Test for SQL IS NOT NULL
`GCnull`	Test for SQL IS NULL
`GCondition`	A GCondition instance is allways the root node of a condition tree.
`GConditionElement`	Abstract base class for all condition elements.
`GCor`	Logical OR.
`GCParam`	Abstract class for parameters.
`GCsub`	Numeric subtraction.
`GCupper`	String conversion to uppercase.
`GUnaryConditionElement`	Abstract base class for all unary condition elements.

Exceptions
`ArgumentCountError`	Number of child elements is incorrect.
`ConditionError`	Abstract base class for all errors in condition definitions.
`ConversionError`	Cannot convert a value.
`ConversionRuleError`	Cannot convert both data types into a common compatible type.
`MalformedConditionTreeError`	Abstract base class for all errors in the structure of the condition tree.
`MissingFieldError`	Cannot find field value on attempt to evaluate a condition.
`UnificationError`	Abstract base class for all errors on unifying different data types.

Function Summary
	`buildCondition(condition, comparison, logic)` Create a condition tree either from a sequence in prefix notation or a dictionary.
	`buildConditionFromDict(dictionary, comparison, logic)` This function creates a new condition tree using the given comparison as operation between keys and values and a given logic as concatenation for all keys.
	`buildConditionFromPrefix(prefixList)` This function creates a new condition tree from the given element sequence, which must be in prefix notation.
	`combineConditions(cond1, cond2)` Combine two conditions using an AND operator.
	`getXMLelements(updates)`
	`unify(values)` Convert all items in a given sequence to the same types.

Function Details

buildCondition(condition, comparison=<class 'gnue.common.datasources.GConditions.GCeq'>, logic=<class 'gnue.common.datasources.GConditions.GCand'>)

Create a condition tree either from a sequence in prefix notation or a dictionary. In the latter case an optional comparison- and logic-operator class might be specified.

Parameters:: condition - sequence in prefix notation or a dictionary with the condition to be converted; comparison - (operator) class used to compare keys and values; logic - (operator) class used to concatenate multiple comparisons

Returns:: GCondition tree

buildConditionFromDict(dictionary, comparison=<class 'gnue.common.datasources.GConditions.GCeq'>, logic=<class 'gnue.common.datasources.GConditions.GCand'>)

This function creates a new condition tree using the given comparison as operation between keys and values and a given logic as concatenation for all keys.

Parameters:: dictionary - dictionary with (key, value) pairs to convert into a condition tree; comparison - (operator) class used to compare keys and values; logic - (operator) class used to concatenate multiple comparisons

Returns:: GCondition tree

buildConditionFromPrefix(prefixList)

This function creates a new condition tree from the given element sequence, which must be in prefix notation.

Parameters:: prefixList - sequence of condition elements in prefix notation

Returns:: GCondition tree

combineConditions(cond1, cond2)

Combine two conditions using an AND operator. Both arguments can be given as condition trees (GCondition), dictionaries or prefix sequences. The resulting combination is a *new* condition tree. None of the arguments will be changed.

Parameters:: cond1 - condition-tree, -dictionary or -sequence (prefix list); cond2 - condition-tree, -dictionary or -sequence (prefix list)

Returns:: new GCondition instance with an AND-combination of both conditions

getXMLelements(updates={})

unify(values)

Convert all items in a given sequence to the same types.

Parameters:: values - sequence of items to be converted to a common type

Returns:: sequence of converted items having all the same datatype.