com.webobjects.jdbcadaptor

Class DB2Expression

java.lang.Object

com.webobjects.eoaccess.EOSQLExpression

com.webobjects.jdbcadaptor.JDBCExpression

com.webobjects.jdbcadaptor.DB2Expression

public class DB2Expression
extends JDBCExpression

DB2 use SQL92 join statements. Has a FETCH FIRST n ROWS statement for limit

Author:

simpson: Took the postgress plugin and made it into a db2 plugin, ak: Regex, NSData, Giorgio Valoti: refactoring, typecasting, schema building, Arturo Perez: JOIN clauses, David Teran: Timestamps handling, Tim Cummings: case sensitive table and column names, cug: hacks for identifier quoting while creating tables

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DB2Expression.JoinClause Helper class that stores a join definition and helps DB2Expression to assemble the correct join clause.

Nested classes/interfaces inherited from class com.webobjects.eoaccess.EOSQLExpression

EOSQLExpression.SQLValue

Field Summary

Fields

Modifier and Type	Field and Description
protected NSMutableArray<DB2Expression.JoinClause>	_alreadyJoined Holds array of join clauses.
protected static Method	_bigDecimalToString Method to get the string value from a BigDecimals from.
protected int	_fetchLimit Fetch spec limit ivar
protected static NSTimestampFormatter	DATE_FORMATTER formatter to use when handling date columns
protected static NSTimestampFormatter	TIMESTAMP_FORMATTER formatter to use when handling timestamps

Fields inherited from class com.webobjects.jdbcadaptor.JDBCExpression

_externalQuoteChar, _inSelect, _jdbcInfo, _rtrimFunctionName

Fields inherited from class com.webobjects.eoaccess.EOSQLExpression

_aliasesByRelationshipPath, _bindings, _contextStack, _defaultDateFormatter, _entity, _joinClauseString, _listString, _NibbleToHex, _orderByString, _statement, _upperFunctionName, _useAliases, _valueListString, _whereClauseString, BindVariableAttributeKey, BindVariableColumnKey, BindVariableNameKey, BindVariablePlaceHolderKey, BindVariableValueKey

Constructor Summary

Constructors

Constructor and Description
DB2Expression(EOEntity entity) Overridden to remove the rtrim usage.

Method Summary

Modifier and Type	Method and Description
void	addCreateClauseForAttribute(EOAttribute attribute)
void	addJoinClause(String leftName, String rightName, int semantic) Overridden to not call the super implementation.
String	allowsNullClauseForConstraint(boolean allowsNull) cug: Quick hack for bug in WebObjects 5.4 where the "not null" statement is added without a space, and "addCreateClauseForAttribute" is not called anymore.
String	assembleJoinClause(String leftName, String rightName, int semantic) Overridden to construct a valid SQL92 JOIN clause as opposed to the Oracle-like SQL the superclass produces.
String	assembleSelectStatementWithAttributes(NSArray attributes, boolean lock, EOQualifier qualifier, NSArray fetchOrder, String selectString, String columnList, String tableList, String whereClause, String joinClause, String orderByClause, String lockClause) Overridden to handle correct placements of join conditions and to handle DISTINCT fetches with compareCaseInsensitiveA(De)scending sort orders.
NSMutableDictionary<String,Object>	bindVariableDictionaryForAttribute(EOAttribute eoattribute, Object obj) Overridden to fix an issue with NStimestamp classes and "T" value-typed attributes.
String	formatValueForAttribute(Object obj, EOAttribute eoattribute) Overridden because the original version throws when the data contains negative byte values.
String	joinClauseString() Overrides the parent implementation to compose the final string expression for the join clauses.
boolean	mustUseBindVariableForAttribute(EOAttribute attribute) Overridden to return true only if bind variables are enabled or the is a data type.
void	prepareConstraintStatementForRelationship(EORelationship relationship, NSArray sourceColumns, NSArray destinationColumns) cug: Also handles identifier quoting now
void	prepareSelectExpressionWithAttributes(NSArray<EOAttribute> attributes, boolean lock, EOFetchSpecification eofetchspecification) Overridden so we can get the fetch limit from the fetchSpec.
static String	replaceStringByStringInString(String old, String newString, String buffer) Replaces a given string by another string in a string.
void	setUseBindVariables(boolean value) Overridden to set the disableBindVariables value correctly.
protected boolean	shouldAllowNull(EOAttribute attribute)
boolean	shouldUseBindVariableForAttribute(EOAttribute attribute) Overridden to return true only if bind variables are enabled or the is a data type.
String	sqlStringForAttribute(EOAttribute attribute) Overridden because the original version does not correctly quote mixed case fields in all cases.
String	tableListWithRootEntity(EOEntity entity) Overridden because the original version does not correctly quote mixed case table names in all cases.
boolean	useBindVariables() Overridden to return the negated value of disableBindVariables.

Methods inherited from class com.webobjects.jdbcadaptor.JDBCExpression

addSelectListAttribute, appendItemToListString, appendItemToOrderByString, appendItemToValueListString, columnTypeStringForAttribute, externalNameQuoteCharacter, jdbcInfo, lockClause, setJDBCInfo

Methods inherited from class com.webobjects.eoaccess.EOSQLExpression

_aliasForRelatedAttributeRelationshipPath, _aliasForRelationshipPath, _defaultDateFormatter, _entityForRelationshipPathOrigin, _flattenRelPathEntity, _listString, _orderByString, _rootEntityForExpression, _setEntity, _sqlStringForJoinSemanticMatchSemantic, _stringForDate, _truncatedString, _truncatedStringForData, _valueList, addBindVariableDictionary, addInsertListAttribute, addOrderByAttributeOrdering, addUpdateListAttribute, aliasesByRelationshipPath, appendItemToListString, assembleDeleteStatementWithQualifier, assembleInsertStatementWithRow, assembleUpdateStatementWithRow, bindVariableDictionaries, entity, formatSQLString, formatStringValue, joinExpression, listString, orderByString, prepareDeleteExpressionForQualifier, prepareInsertExpressionWithRow, prepareUpdateExpressionWithRow, setStatement, setUseAliases, setUseQuotedExternalNames, sqlEscapeChar, sqlPatternFromShellPattern, sqlPatternFromShellPatternWithEscapeCharacter, sqlStringForAttributeNamed, sqlStringForAttributePath, sqlStringForCaseInsensitiveLike, sqlStringForConjoinedQualifiers, sqlStringForData, sqlStringForDisjoinedQualifiers, sqlStringForKeyComparisonQualifier, sqlStringForKeyValueQualifier, sqlStringForNegatedQualifier, sqlStringForNumber, sqlStringForQualifier, sqlStringForSchemaObjectName, sqlStringForSelector, sqlStringForString, sqlStringForValue, statement, toString, useAliases, useQuotedExternalNames, valueList, whereClauseString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

DATE_FORMATTER

protected static final NSTimestampFormatter DATE_FORMATTER

formatter to use when handling date columns

TIMESTAMP_FORMATTER

protected static final NSTimestampFormatter TIMESTAMP_FORMATTER

formatter to use when handling timestamps

_bigDecimalToString

protected static Method _bigDecimalToString

Method to get the string value from a BigDecimals from.

_alreadyJoined

protected NSMutableArray<DB2Expression.JoinClause> _alreadyJoined

Holds array of join clauses.

_fetchLimit

protected int _fetchLimit

Fetch spec limit ivar

Constructor Detail

DB2Expression

public DB2Expression(EOEntity entity)

Overridden to remove the rtrim usage. The original implementation will remove every trailing space from character based column which should not be OK for DB2.

Parameters:

entity - entity for this expression

Method Detail

bindVariableDictionaryForAttribute

public NSMutableDictionary<String,Object> bindVariableDictionaryForAttribute(EOAttribute eoattribute,
                                                                             Object obj)

Overridden to fix an issue with NStimestamp classes and "T" value-typed attributes.

Overrides:

bindVariableDictionaryForAttribute in class JDBCExpression

addJoinClause

public void addJoinClause(String leftName,
                          String rightName,
                          int semantic)

Overridden to not call the super implementation.

Overrides:

addJoinClause in class EOSQLExpression

Parameters:

leftName - the table name on the left side of the clause

rightName - the table name on the right side of the clause

semantic - the join semantic

assembleJoinClause

public String assembleJoinClause(String leftName,
                                 String rightName,
                                 int semantic)

Overridden to construct a valid SQL92 JOIN clause as opposed to the Oracle-like SQL the superclass produces.

Overrides:

assembleJoinClause in class EOSQLExpression

Parameters:

leftName - the table name on the left side of the clause

rightName - the table name on the right side of the clause

semantic - the join semantic

Returns:

the join clause

assembleSelectStatementWithAttributes

public String assembleSelectStatementWithAttributes(NSArray attributes,
                                                    boolean lock,
                                                    EOQualifier qualifier,
                                                    NSArray fetchOrder,
                                                    String selectString,
                                                    String columnList,
                                                    String tableList,
                                                    String whereClause,
                                                    String joinClause,
                                                    String orderByClause,
                                                    String lockClause)

Overridden to handle correct placements of join conditions and to handle DISTINCT fetches with compareCaseInsensitiveA(De)scending sort orders. Change from Postgres to use Fetch First rows only rather then limit

Overrides:

assembleSelectStatementWithAttributes in class EOSQLExpression

Parameters:

attributes - the attributes to select

lock - flag for locking rows in the database

qualifier - the qualifier to restrict the selection

fetchOrder - specifies the fetch order

columnList - the SQL columns to be fetched

tableList - the the SQL tables to be fetched

whereClause - the SQL where clause

joinClause - the SQL join clause

orderByClause - the SQL sort order clause

lockClause - the SQL lock clause

Returns:

the select statement

formatValueForAttribute

public String formatValueForAttribute(Object obj,
                                      EOAttribute eoattribute)

Overridden because the original version throws when the data contains negative byte values.

Overrides:

formatValueForAttribute in class JDBCExpression

Parameters:

obj - the object used in the SQL statement

eoattribute - the attribute associated with obj

Returns:

the formatted string

joinClauseString

public String joinClauseString()

Overrides the parent implementation to compose the final string expression for the join clauses.

Overrides:

joinClauseString in class EOSQLExpression

prepareConstraintStatementForRelationship

public void prepareConstraintStatementForRelationship(EORelationship relationship,
                                                      NSArray sourceColumns,
                                                      NSArray destinationColumns)

cug: Also handles identifier quoting now

Overrides:

prepareConstraintStatementForRelationship in class EOSQLExpression

Parameters:

relationship - the relationship

sourceColumns - the source columns for the constraints

destinationColumns - the destination columns for the constraints

prepareSelectExpressionWithAttributes

public void prepareSelectExpressionWithAttributes(NSArray<EOAttribute> attributes,
                                                  boolean lock,
                                                  EOFetchSpecification eofetchspecification)

Overridden so we can get the fetch limit from the fetchSpec.

Overrides:

prepareSelectExpressionWithAttributes in class JDBCExpression

Parameters:

attributes - the array of attributes

lock - locking flag

eofetchspecification - the fetch specification

shouldAllowNull

protected boolean shouldAllowNull(EOAttribute attribute)

addCreateClauseForAttribute

public void addCreateClauseForAttribute(EOAttribute attribute)

Overrides:

addCreateClauseForAttribute in class EOSQLExpression

allowsNullClauseForConstraint

public String allowsNullClauseForConstraint(boolean allowsNull)

cug: Quick hack for bug in WebObjects 5.4 where the "not null" statement is added without a space, and "addCreateClauseForAttribute" is not called anymore. Will probably change.

Overrides:

allowsNullClauseForConstraint in class JDBCExpression

sqlStringForAttribute

public String sqlStringForAttribute(EOAttribute attribute)

Overridden because the original version does not correctly quote mixed case fields in all cases. SELECT statements were OK (useAliases is true) INSERT, UPDATE, DELETE didn't quote mixed case field names.

Overrides:

sqlStringForAttribute in class EOSQLExpression

Parameters:

attribute - the attribute (column name) to be converted to a SQL string

Returns:

SQL string for the attribute

tableListWithRootEntity

public String tableListWithRootEntity(EOEntity entity)

Overridden because the original version does not correctly quote mixed case table names in all cases. SELECT statements were OK (useAliases is true) INSERT, UPDATE, DELETE didn't quote mixed case field names.

Overrides:

tableListWithRootEntity in class EOSQLExpression

Returns:

the SQL string for the table names

useBindVariables

public boolean useBindVariables()

Overridden to return the negated value of disableBindVariables.

Overrides:

useBindVariables in class JDBCExpression

setUseBindVariables

public void setUseBindVariables(boolean value)

Overridden to set the disableBindVariables value correctly.

Overrides:

setUseBindVariables in class EOSQLExpression

Parameters:

value - new value

shouldUseBindVariableForAttribute

public boolean shouldUseBindVariableForAttribute(EOAttribute attribute)

Overridden to return true only if bind variables are enabled or the is a data type.

Overrides:

shouldUseBindVariableForAttribute in class JDBCExpression

mustUseBindVariableForAttribute

public boolean mustUseBindVariableForAttribute(EOAttribute attribute)

Overridden to return true only if bind variables are enabled or the is a data type.

Overrides:

mustUseBindVariableForAttribute in class JDBCExpression

replaceStringByStringInString

public static String replaceStringByStringInString(String old,
                                                   String newString,
                                                   String buffer)

Replaces a given string by another string in a string.

Parameters:

old - string to be replaced

newString - to be inserted

buffer - string to have the replacement done on it

Returns:

string after having all of the replacement done.