__init__(self, anEntity=None)
(Constructor)

Overrides:

__builtin__.object.__init__

addCreateClauseForAttribute(self, attribute)

Adds the create clause for the supplied 'attribute' to the receiver's listString. The default implementation appends a line of the following form:

<newline><COLUMN_NAME> <COLUMN_TYPE_STRING> <ALLOWS_NULL_CLAUSE>

where <COLUMN_NAME> is the attribute's columnName(), <COLUMN_TYPE_STRING> is 'columnTypeStringForAttribute(attribute)' and <ALLOWS_NULL_CLAUSE> is 'allowsNullClauseForConstraint(attribute.allowsNull())'.

See also:

appendItemToListString() listString() allowsNullClauseForConstraint() columnTypeStringForAttribute() SchemaGeneration.createTableStatementsForEntityGroup()

addInsertListAttribute(self, attribute, value)

Parameters:

attribute -- an Attribute object

value -- the value to store

addSelectListAttribute(self, attribute)

Adds the sqlStringForAttributeNamed(attribute.name()) to the SQLExpression's listString().

See also: sqlStringForAttributeNamed(), appendItemToListString(),

listString()

addUpdateListAttribute(self, attribute, value)

Uses appendItemToListString() to add to listString() a string formatted that way:

<attribute's columnName()> = <value>

See also: prepareUpdateExpressionWithRow(), listString()

aliasesByRelationshipPath(self)

Returns the dictionary of table aliases used by the SQLExpression ; the keys are relationshipPath and the values are the corresponding table aliases.

If useAliases() is true, the dictionary contains at least one entry with an empty string as the key and 't0' being the corresponding value. Otherwise, it may be None.

That dictionary is built upon successive invocation of sqlStringForAttributePath().

See also: setUseAliases(),

sqlStringForAttributePath(), sqlStringForAttributeNamed()

allowsNullClauseForConstraint(self, flag)

Returns 'NOT NULL' is flag is false, '' (empty string) otherwise.

Subclasses should override this method, without calling it, if the underlying database uses a different syntax for such a clause.

See: addCreateClauseForAttribute()

appendItemToListString(self, itemString, aStringIO)

Appends 'itemString' to 'aStringIO' ; if aStringIO is not empty, a comma is appended to aStringIO before 'itemString'

Parameters:

• itemString is the string to append
• aStringIO is a StringIO object

See:

addCreateClauseForAttribute()

assembleDeleteStatementWithQualifier(self, aQualifier, tableList, whereClause)

Generates the SQL DELETE statement and assigns it to self's statement() The generated statement has the following format:

DELETE FROM <tableList> WHERE <whereClause>

Parameters:

aQualifier -- identifies the rows to be deleted. This is usually the

parameter that prepareDeleteExpressionForQualifier() received before this method is called. It is not used here but might be useful for subclasses' implementation

tableList -- the name of the table in which the row should be deleted

whereClause -- the SQL where clause to use in the DELETE statement.

See also: statement(), prepareDeleteExpressionForQualifier()

assembleInsertStatementWithRow(self, row, tableList, columnList, valueList)

Generates the SQL INSERT statement and assigns it to self's statement() The generated statement has the following format:

INSERT INTO <tableList> [<columnList>] VALUES <valueList>

<columnList> will be omitted

Parameters:

row -- the 'row' parameter that was passed to

prepareInsertExpressionWithRow(). It is not used here but might be useful for subclasses' implementation

tableList -- the name of the table in which the row should be inserted

columnList -- a comma-separated string containing the name of the

columns (order: see below)

valueList -- a comma-separated string of values to be inserted in the

'tableList'. 'columnList' and 'valueList' should have the same order, i.e. entries in the former correspond one-to-one to entries in the latter.

See also: statement(), prepareInsertExpressionWithRow()

assembleUpdateStatementWithRow(self, row, aQualifier, tableList, updateList, whereClause)

Generates the SQL INSERT statement and assigns it to self's statement() The generated statement has the following format:

UPDATE <tableList> SET <updateList> WHERE <whereClause>

Parameters:

row --

aQualifier -- identifies the rows to be deleted. This is usually the

parameter that prepareDeleteExpressionForQualifier() received before this method is called. It is not used here but might be useful for subclasses' implementation

tableList -- the name of the table in which the row should be updated

updateList -- the SQL where clause to use in the UPDATE's SET statement.

whereClause -- the SQL where clause to use in the UPDATE's WHERE

statement.

See also: statement(), prepareUpdateExpressionWithRow()

columnTypeStringForAttribute(self, attribute)

Returns the string corresponding to the attribute's column type definition when creating a table.

Default implementation returns a different string depending on some of the attribute's properties:

• if attribute's precision is not zero: 'externalType(precision, scale)'
• if attribute's width is not zero: 'externalType(width)'
• otherwise returns: 'externalType'

Subclasses should override this method, without calling it, if the underlying database uses a different syntax for column types.

See also:

addCreateClauseForAttribute() SchemaGeneration.createTableStatementsForEntityGroup()

entity(self)

Returns the Entity bound to that SQLExpression

See: __init__()

externalNameQuoteCharacter(self)

formatSQLString(self, sqlString, format)

formatStringValue(self, string)

formatValueForAttribute(self, value, attribute)

Examines the attribute's externalType and forwards the request to the appropriate method.

The methods to which the message is forwarded are:

• for BinaryType: sqlStringForData()
• for CharacterType: sqlStringForString()
• for DateType: sqlStringForDate()
• for NumericType: sqlStringForNumber()

Raises InvalidSQLTypeError is the attribute's external type is unknown for the concrete adaptor.

See also: valueTypeForExternalType(), sqlStringForValue()

joinClauseString(self)

joinExpression(self)

listString(self)

Has a different meaning depending on what the SQLExpression was made for:

• for createTableStatements, it holds the list of columns' type declarations
• for insert statements, it holds the list of column's names (see also: valueList())
• for update statements, contains the SQL clause suitable for the SET

statement (in: 'UPDATE ... SET ... WHERE ...')

prepareDeleteExpressionForQualifier(self, aQualifier)

Prepares the internal state to generate a SQL delete statement, according to entity() and parameter 'aQualifier'.

The process is the following:

• the use of aliases is disabled (see setUseAliases())

• the whereClauseString() is compuuted ans set by calling

  'sqlStringForQualifier(aQualifier)' on itself,

• the database table is computed by calling tableListWithRootEntity()

• Finally, we send to oneself 'assembleDeleteStatementWithQualifier()'

See also: assembleDeleteStatementWithQualifier(), whereClauseString()

prepareInsertExpressionWithRow(self, row)

Generates an INSERT statement for the supplied 'row' and the SQLExpression's entity().

The process is the following:

• the use of aliases is disabled (see setUseAliases())
• it calls addInsertListAttribute() on 'self' for each item in 'row'. Afterwards, listString() contains a comma-separated list of column's name, and valueList() a comma-separated list of their values, both following the same order, of course.
• it gets the name of the table by sending the message tableListWithRootEntity to itself
• finally, it calls assembleInsertStatementWithRow() with the elements calculated above.

The generated INSERT statement is then available through 'statement()'

Parameter:

row -- a dictionary, with keys as Attribute's names, which are bound to

their corresponding values.

See also: assembleInsertStatementWithRow(), listString(), valueList(),

statement()

prepareSelectCountExpressionWithAttributes(self, attributes, lock, fetchSpec)

Prepares a 'SELECT' statement from retrieving the number of rows corresponding to the request. The statement is then available as a string in self.statement().

See also: AdaptorChannel.rowCountForSelectAttributes()

prepareSelectExpressionWithAttributes(self, attributes, lock, fetchSpec)

Prepares a 'SELECT' statement. The statement is then available as a string in self.statement().

See also: AdaptorChannel.selectAttributes()

prepareUpdateExpressionWithRow(self, row, aQualifier)

Parameters:

row -- a dictionary {key==attributeName: value==value to update}

aQualifier -- identifies the rows to be updated.

setStatement(self, statement)

setUseAliases(self, useAliases)

Tells the SQLExpression whether it should use table aliases.

This method has a side-effect: if flag 'useAliases' is true and the SQLExpression's aliasesByRelationshipPath() is empty, the latter gets value 't0' for key '""' (empty string) ; if the flag is false, aliasesByRelationshipPath() is reset.

See also: useAliases()

setUseBindVariables(self, flag)

shouldUseBindVariableForAttribute(self, attribute)

sqlPatternFromShellPattern(self, pattern)

sqlPatternFromShellPatternWithEscapeCharacter(self, pattern, escapeChar)

Transforms the shell 'pattern', using '*' and '?' as wildcards (the former matches 0 to many characters while the second matches one character) to an valid SQL pattern.

Details: '%' in 'pattern' becomes '%', '_' becomes '_',

'*' becomes '*', '*' becomes '%', '?' becomes '?' and '?' becomes '_'.

sqlStringForAttribute(self, attribute)

Returns the attribute's columnName, prepended with the table alias for the empty string if the SQLExpression uses table aliases.

For example, the returned value for an attribute 'title' whose columnName is 'TITLE' is 'TITLE', or 't0.TITLE' if useAliases() is true.

See also: useAliases(), aliasesByRelationshipPath(), Attribute.columnName()

sqlStringForAttributeNamed(self, name)

Returns the sql string for the attribute 'name'. If the corresponding attribute is a regular Attribute (non flattened), it triggers sqlStringForAttribute() ; otherwise, it builds the path and triggers sqlStringForAttributePath() (see sqlStringForAttributePath() for a description of what 'building the path' means).

Raises ValueError in case 'name' is not a valid attribute's name.

See also: sqlStringForAttribute, sqlStringForAttributePath()

Attribute.isFlattened(), Attribute.relationshipPathObjects(), Attribute.finalAttribute()

sqlStringForAttributePath(self, path)

Given a path (see below), builds the corresponding sql string, completed with a table alias if the SQLExpression useAliases().

Parameter 'path' is a list composed of Relationship objects that has to be traversed to access the final Attribute, which is the last element of the list.

If table aliases is on and aliasesByRelationshipPath() has no key corresponding to the relationshipPath, that key is set with a new table alias.

Example: say we have two entities 'Book' and 'Writer', a toOne relationship 'toBook' from 'Writer' to 'Book', and 'Writer' defined an attribute 'bookTitle' flattening 'toBook.title' (title being a regular attribute of 'Book'). When table aliases is on, this methods returns something like 't1.TITLE' --in that case, aliasesByRelationshipPath() has a key 'toBook' corresponding to the value 't1'.

Important note:

It seems that derived attribute should not be used except to support inheritance and the vertical-mapping approach. This is not supported for the moment being, thus this method is desactivated and will unconditionnally raise when invoked. See the project's TODO file for a more complete explanation.

See also: useAliases(), sqlStringForAttribute(),

aliasesByRelationshipPath(), Attribute.relationshipPathObjects(), Attribute.finalAttribute()

sqlStringForCaseInsensitiveLike(self, keyString, valueString)

Returns the SQL string, to be inserted in a WHERE clause, for case-insensitive comparison between a lvalue and a rvalue.

Default implementation returns the following string:

UPPER(<keyString>) LIKE UPPER(<valueString>)

Parameters:

keyString -- the left value

valueString -- the right value

See also: sqlStringForKeyValueQualifier(),

sqlStringForKeyComparisonQualifier()

sqlStringForConjoinedQualifiers(self, qualifiers)

Returns the SQL string, to be inserted in a WHERE clause, for the supplied ``to-be-conjoined'' qualifiers.

Default implementation returns:

<qualifierString1> AND <qualifierString2> AND ...
      ... AND <qualifierString_i>

where '<qualifierString_i>' is 'sqlStringForQualifier(qualifiers[i])'

Parameter:

qualifiers -- a sequence of qualifier that should be conjoined. If you

have a 'Qualifier.AndQualifier' instance 'andQualifier', you should supply 'andQualifier.qualifiers()' as the argument

See also: sqlStringForQualifier()

sqlStringForData(self, data)

sqlStringForDate(self, aDate)

Formats the 'mxDateTime.DateTime' object 'aDate'. SQLExpression's implementation simply returns 'str(aDate)', or 'NULL' if 'aDate' is None.

See also: formatValueForAttribute()

sqlStringForDisjoinedQualifiers(self, qualifiers)

Returns the SQL string, to be inserted in a WHERE clause, for the supplied ``to-be-disjoined'' qualifiers.

Default implementation returns:

<qualifierString1> OR <qualifierString2> OR ... OR <qualifierString_i>

where '<qualifierString_i>' is 'sqlStringForQualifier(qualifiers[i])'

Parameter:

qualifiers -- a sequence of qualifier that should be disjoined. If you

have a 'Qualifier.OrQualifier' instance 'orQualifier', you should supply 'orQualifier.qualifiers()' as the argument

See also: sqlStringForQualifier()

sqlStringForInOperatorValue(self, aList, key)

Returns the SQL string suitable for operator IN and NOT IN. The returned string is a comma-separated list of the values in aList, surrounded by brackets.

Example: aList=[1], return '(1)'

aList=(1,2,4), return '(1, 2, 4)'

sqlStringForKeyComparisonQualifier(self, aQualifier)

Returns the SQL string for the KeyComparisonQualifier supplied.

It is of the form:

<left_columnName> <operator> <right_columnName>

such as in:

t0.LAST_NAME != t2.FIRST_NAME

Both column names are returned by sqlStringForAttributeNamed(), and the operator is computed by sqlStringForSelector().

When the quelifier's operator is Qualifier.QualifierOperatorCaseInsensitiveLike, the returned string is calculated by sqlStringForCaseInsensitiveLike.

Parameter:

aQualifier -- a Qualifier.KeyComparisonQualifier instance

See also: sqlStringForQualifier()

sqlStringForKeyValueQualifier(self, aQualifier)

Returns the SQL string for the KeyValueQualifier supplied.

It is of the form:

<key> <operator> <value>

such as in:

t0.LAST_NAME LIKE 'R%'

'key' is returned by sqlStringForAttributeNamed(), 'operator', by sqlStringForSelector(), and 'value': by sqlStringForValue(), or by sqlPatternFromShellPattern() is the qualifier's operator is 'LIKE' or case-insensitive-LIKE (and, when the case-insensitive form of 'LIKE' is used, the returned string is computed by sqlStringForCaseInsensitiveLike)

Parameter:

aQualifier -- a Qualifier.KeyValueQualifier instance

See also: sqlStringForQualifier()

sqlStringForNegatedQualifier(self, aQualifier)

Returns the SQL string for the supplied Qualifier

The string returned is:

NOT (<qualification>)

where 'qualification' is 'sqlStringForQualifier(aQualifier)'

Parameter:

aQualifier -- the qualifier to negate, NOT the corresponding

'NotQualifier'. If 'notQualifier' is is Qualifier.NotQualifier, you should supply 'notQualifier.qualifier()' as the argument.

sqlStringForNumber(self, aNumber, keyPath='')

Formats 'aNumber' and returns the string suitable for inclusion in a SQL statement. SQLExpression's implementation simply returns 'str(aNumber)', or 'NULL' if 'aDate' is None.

See also: formatValueForAttribute()

sqlStringForQualifier(self, aQualifier)

Returns the SQL WHERE clause string built from 'aQualifier' ; NB: the generated statement does not include the 'WHERE' SQL keyword.

Default implementation delegates the actual generation of the SQL string to the appropriate method [sqlStringFor...Qualifier()], depending on aQualifier's type/class.

Note that this method does not set the whereClauseString() ; it is the responsability for the caller to set it when appropriate.

See also: whereClauseString(),

sqlStringForKeyValueQualifier(), sqlStringForNegatedQualifier(), sqlStringForKeyComparisonQualifier(), sqlStringForDisjoinedQualifiers(), sqlStringForConjoinedQualifiers(), prepareInsertExpressionWithRow(), prepareSelectExpressionWithAttributes()

sqlStringForSchemaObjectName(self, name)

sqlStringForSelector(self, selector, value)

Returns the appropriate SQL string corresponding to 'selector'

Parameters:

selector -- an operator of module Qualifier (QualifierOperatorEqual,

etc.)

value -- the right-value used with the operator

Depending on 'operator', the returned value is:

• for 'QualifierOperatorEqual': '=' is 'value' is not None, 'IS' otherwise
• for 'QualifierOperatorNotEqual': '<>' is 'value' is not None, 'IS NOT' otherwise
• for 'QualifierOperatorGreaterThan': '>'
• for 'QualifierOperatorGreaterThanOrEqualTo': '>='
• for 'QualifierOperatorLessThan': '<'
• for 'QualifierOperatorLessThanOrEqualTo': '<='
• for 'QualifierOperatorLike': 'LIKE'

Raise 'ValueError' if 'selector' is not in that list. Note that 'QualifierOperatorCaseInsensitiveLike' is not in the list: this is intended. Specific transformations for this operator are handled by the specific methods sqlStringForKeyValueQualifier(), etc.

See also: sqlStringForKeyValueQualifier() and others related methods

sqlStringForString(self, aString)

Formats 'aString' and returns the string suitable for inclusion in a SQL statement. SQLExpression's implementation surrounds the string with simple quotes, and back-quotes any simple quotes 'aString' may have. It returns 'NULL' if 'aString' is None.

See also: formatValueForAttribute()

sqlStringForValue(self, value, keyPath)

Simply calls formatValueForAttribute() and return the formatted string

Implementation note: when SQL bind variable are supported this should update the bindings dictionary and return the name of the bind variable.

statement(self)

Returns the statement assigned to this object. The statement could have been set either with 'setStatement()' or by any of the following methods:

• prepareDeleteExpressionForQualifier()
• prepareInsertExpressionWithRow()
• prepareSelectExpressionWithAttributes()
• prepareUpdateExpressionWithRow()

toString(self)

useAliases(self)

Returns whether the SQLExpression uses table aliases.

See also: setUseAliases()

useBindVariables(self)

valueList(self)

This is set when prepareInsertExpressionWithRow() is called, and it holds the list of values to insert.

Returned value is a string, such as:

"12, 'Hugo', 'Victor', NULL"

See also: listString(), prepareInsertExpressionWithRow()

valueTypeForExternalType(self, externalTypeName)

Returns the value type corresponding to 'externalTypeName'.

The correspondance table is the following:

• char, varchar: CharacterType
• int, integer: NumericType
• float, numeric: NumericType
• date, time, timestamp: DateType

Returns None when no corresponding value type can be found.

Parameter:

externalTypeName -- a SQL datatype. It is lower-cased before

valueTypeForExternalTypeMapping() is asked for the corresponding value type.

See also: formatValueForAttribute(), valueTypeForExternalTypeMapping()

valueTypeForExternalTypeMapping(self)

Returns a dictionary consisting of the valid SQL types, each of which being a key bound to either 'BinaryType', 'CharacterType', 'DateType' or 'NumericType' (module's constants)

Important: the SQL types should be lower-cased

Default implementation returns:

{ 'char': CharacterType,
  'float': NumericType,
  'int': NumericType,
  'integer': NumericType,
  'numeric': NumericType,
  'date': DateType,
  'time': DateType,
  'timestamp': DateType,
  'varchar': CharacterType,
  }

See also: valueTypeForExternalType()

whereClauseString(self)

Returns the WHERE clause string generated for a given SQL statement.

This is set by: prepareInsertExpressionWithRow(), prepareSelectExpressionWithAttributes()