Whats New with Data and Whats New with Data and SQL in Visual FoxPro 9.0SQL in Visual FoxPro 9.0

Data Language, Datatypes, Data Language, Datatypes, CursorAdapter & XMLAdapterCursorAdapter & XMLAdapter

Overview: What’s New with Overview: What’s New with Data?Data?

SQLSQL MORE!MORE! Enhanced sub-query Enhanced sub-query

supportsupport Enhanced correlation Enhanced correlation

supportsupport Enhanced UNION supportEnhanced UNION support

PerformancePerformance Commands & FunctionsCommands & Functions DatatypesDatatypes

Remote DataRemote Data CursorAdapterCursorAdapter XMLAdapterXMLAdapter SQL Pass-through (SPT)SQL Pass-through (SPT) OLEDB Provider OLEDB Provider

EnhancementsEnhancements

SQL - More!SQL - More!

Amount of JOINs and amount of sub-Amount of JOINs and amount of sub-queries in SQL statement. .queries in SQL statement. .

Amount of UNIONs in SQL SELECT Amount of UNIONs in SQL SELECT statement. statement.

Amount of tables referenced by SQL Amount of tables referenced by SQL statement. statement.

More than 24 items in IN list. More than 24 items in IN list. Multiple sub-query nesting.Multiple sub-query nesting.

* No hard coded limit!

SQL - Enhanced sub-query SQL - Enhanced sub-query supportsupport

Sub-query in Sub-query in SELECTSELECT list (projection).   list (projection).   Sub-query in Sub-query in FROMFROM clause (derived).  clause (derived).  Sub-query in UPDATE SET list.  Sub-query in UPDATE SET list.   ORDER BY in conjunction with TOP N ORDER BY in conjunction with TOP N

inside of non-correlated sub-queryinside of non-correlated sub-query Support for more complex expressions Support for more complex expressions

on the left side in comparison with sub-on the left side in comparison with sub-queryquery

SQL - Enhanced correlation SQL - Enhanced correlation supportsupport

Correlated UPDATE … FROM  .  Correlated UPDATE … FROM  .   Correlated DELETE  … FROM .  Correlated DELETE  … FROM .   GROUP BY in correlated sub-queryGROUP BY in correlated sub-query

SELECT * ;SELECT * ; FROM foo1 T1 ; FROM foo1 T1 ; WHERE f1 IN (SELECT MAX(f1); WHERE f1 IN (SELECT MAX(f1); FROM foo2 T2 ; FROM foo2 T2 ; WHERE T2.f2 = T1.f2; WHERE T2.f2 = T1.f2; GROUP BY f3) GROUP BY f3)

SQL - Enhanced UNION SQL - Enhanced UNION supportsupport

UNION in INSERT INTO ... SELECT ... UNION in INSERT INTO ... SELECT ... FROM ... FROM ...

ORDER BY <field name> when using ORDER BY <field name> when using UNIONUNION Referenced fields must be present in Referenced fields must be present in

SELECT list for the last SELECT in the SELECT list for the last SELECT in the UNION.UNION.

PerformancePerformance

TOP N performance improvement TOP N performance improvement MIN()/MAX() optimization MIN()/MAX() optimization Rushmore optimization changes Rushmore optimization changes

LIKE LIKE INDEX ON DELETED() / NOT DELETED()INDEX ON DELETED() / NOT DELETED()

INDEX ON…FOR DELETED() / NOT DELETED()INDEX ON…FOR DELETED() / NOT DELETED()

Rushmore OptimizationRushmore Optimization

INDEX ON !DELETED() will be used to INDEX ON !DELETED() will be used to optimize !DELETED() or DELETED() optimize !DELETED() or DELETED() conditions when INDEX ON DELETED() is conditions when INDEX ON DELETED() is not present.not present.

INDEX ON <…> FOR !DELETED() will be INDEX ON <…> FOR !DELETED() will be used to optimize !DELETED() or DELETED() used to optimize !DELETED() or DELETED() when neither INDEX ON DELETED() or when neither INDEX ON DELETED() or INDEX ON !DELETED() is present.INDEX ON !DELETED() is present.

Rushmore OptimizationRushmore Optimization

When ever it is possible to determine that a When ever it is possible to determine that a Query should filter on DELETED() or !Query should filter on DELETED() or !DELETED() a filtered index FOR DELETED() DELETED() a filtered index FOR DELETED() or FOR !DELETED() will be used accordingly or FOR !DELETED() will be used accordingly if no non-filtered index exists.if no non-filtered index exists.

If only indexes filtered FOR !DELETED() were If only indexes filtered FOR !DELETED() were used for Rushmore optimization and SET used for Rushmore optimization and SET DELETED is ON, additional !DELETED() DELETED is ON, additional !DELETED() optimization is not done as it is optimization is not done as it is unnecessary.unnecessary.

Language EnhancementsLanguage Enhancements

BINARY index type …BINARY index type …      

SET REFRESH changesSET REFRESH changes

CursorSetProp("Refresh") .CursorSetProp("Refresh") .

SYS(1104,[cAlias | nWorkarea])SYS(1104,[cAlias | nWorkarea])

FLUSH [{ IN<nWorkArea>|<cTableAlias>}|<cFileSpec>] [ FORCE ]FLUSH [{ IN<nWorkArea>|<cTableAlias>}|<cFileSpec>] [ FORCE ]

SYS(3092) output to a fileSYS(3092) output to a file

SET SQLBUFFERING / SELECT … WITH (Buffering = <lexpr>)SET SQLBUFFERING / SELECT … WITH (Buffering = <lexpr>)

CAST()CAST()

ICASE()ICASE()

New DatatypesNew DatatypesVarCharVarChar

Similar to char data type except filled Similar to char data type except filled value is not padded (or trimmed) with value is not padded (or trimmed) with spaces if value is assigned explicitly or by spaces if value is assigned explicitly or by means of default value.means of default value.

Fields from external sources that do not fit Fields from external sources that do not fit into Varchar limits will map to Memo.into Varchar limits will map to Memo.

VarChar has priority over CharacterVarChar has priority over Character Index has same structure as CharacterIndex has same structure as Character Uses:Uses:

Reduce size of indexesReduce size of indexes With SQL Server VarChar (when < 254 bytes)With SQL Server VarChar (when < 254 bytes)

New DatatypesNew DatatypesVarBinaryVarBinary

Similar to VarChar except used to Similar to VarChar except used to store binary data.store binary data.

NO CPTRANSNO CPTRANS Uses:Uses:

TimeStamp (native)TimeStamp (native) GUIDGUID Map to VarBinary in SQL ServerMap to VarBinary in SQL Server

New DatatypesNew DatatypesBLOBBLOB

Similar to Memo data type except it’s Similar to Memo data type except it’s treated as a true binary data type. treated as a true binary data type.

NO CPTRANSNO CPTRANS MODI MEMO displays HEX dumpMODI MEMO displays HEX dump SCATTER/GATHER MEMOSCATTER/GATHER MEMO Uses:Uses:

Image.PictureVal (Goodbye General!)Image.PictureVal (Goodbye General!) Map to BLOB in SQL ServerMap to BLOB in SQL Server

Comparison rulesComparison rules

Type on Left Padding Case SensitiveType on Left Padding Case Sensitive------------- --------- ---------------------------- --------- ---------------Binary CHR(0) AlwaysBinary CHR(0) AlwaysCharacter CHR(32) SET COLLATE dependentCharacter CHR(32) SET COLLATE dependent

New DatatypesNew DatatypesSET EXACT & Binary DataSET EXACT & Binary Data

SET COLLATE TO MACHINESET COLLATE TO MACHINESET EXACT OFFSET EXACT OFF expression C=C Q=C C=Q Q=Q expression C=C Q=C C=Q Q=Q--------------- --- --- --- ------------------ --- --- --- ---"abc" = "abc" .T. .T. .T. .T."abc" = "abc" .T. .T. .T. .T."abc " = "abc" .T. .T. .T. .T."abc " = "abc" .T. .T. .T. .T."abc" = "abc " .F. .F. .F. .F."abc" = "abc " .F. .F. .F. .F."abc" = "ABC" .F. .F. .F. .F."abc" = "ABC" .F. .F. .F. .F."ABC" = "abc" .F. .F. .F. .F."ABC" = "abc" .F. .F. .F. .F.

SET COLLATE TO MACHINESET COLLATE TO MACHINESET EXACT ONSET EXACT ON expression C=C Q=C C=Q Q=Q expression C=C Q=C C=Q Q=Q--------------- --- --- --- ------------------ --- --- --- ---"abc" = "abc" .T. .T. .T. .T."abc" = "abc" .T. .T. .T. .T."abc " = "abc" .T. .F. .T. .F."abc " = "abc" .T. .F. .T. .F."abc" = "abc " .T. .F. .T. .F."abc" = "abc " .T. .F. .T. .F."abc" = "ABC" .F. .F. .F. .F."abc" = "ABC" .F. .F. .F. .F."ABC" = "abc" .F. .F. .F. .F."ABC" = "abc" .F. .F. .F. .F.

SET COLLATE TO GENERAL SET COLLATE TO GENERAL SET EXACT OFFSET EXACT OFF

expression C=C Q=C C=Q Q=Q expression C=C Q=C C=Q Q=Q--------------- --- --- --- ------------------ --- --- --- ---"abc" = "abc" .T. .T. .T. .T."abc" = "abc" .T. .T. .T. .T."abc " = "abc" .T. .T. .T. .T."abc " = "abc" .T. .T. .T. .T."abc" = "abc " .F. .F. .F. .F."abc" = "abc " .F. .F. .F. .F."abc" = "ABC" .T. .F. .T. .F."abc" = "ABC" .T. .F. .T. .F."ABC" = "abc" .T. .F. .T. .F."ABC" = "abc" .T. .F. .T. .F.

SET COLLATE TO GENERALSET COLLATE TO GENERALSET EXACT ON SET EXACT ON

expression C=C Q=C C=Q Q=Q expression C=C Q=C C=Q Q=Q--------------- --- --- --- ------------------ --- --- --- ---"abc" = "abc" .T. .T. .T. .T."abc" = "abc" .T. .T. .T. .T."abc " = "abc" .T. .F. .T. .F."abc " = "abc" .T. .F. .T. .F."abc" = "abc " .T. .F. .T. .F."abc" = "abc " .T. .F. .T. .F."abc" = "ABC" .T. .F. .T. .F."abc" = "ABC" .T. .F. .T. .F."ABC" = "abc" .T. .F. .T. .F."ABC" = "abc" .T. .F. .T. .F.

Remote DataRemote Data

DisconnectRollbackDisconnectRollback Determines whether pending transaction has Determines whether pending transaction has

to be rolled back when connection is being to be rolled back when connection is being disconnected. default (.F.) disconnected. default (.F.)

RecordsFetchedRecordsFetched Returns amount of records currently fetched Returns amount of records currently fetched

from the back end for ODBC/ADO based cursor.from the back end for ODBC/ADO based cursor. FetchIsCompleteFetchIsComplete

Returns .T. if fetch process for the ODBC/ADO Returns .T. if fetch process for the ODBC/ADO based cursor is complete.based cursor is complete.

SPTSPT

Ability to determine amount of records Ability to determine amount of records affected by an SPT execution.affected by an SPT execution. Via additional parameter for SQLEXEC and Via additional parameter for SQLEXEC and

SQLMORERESULTS functions:SQLMORERESULTS functions: aCountInfo – aCountInfo – Provides name of the array to populate Provides name of the array to populate

with row count information. Array contains two with row count information. Array contains two columns: 1 – columns: 1 – AliasAlias, 2 –, 2 –CountCount. .

SQLIDLEDISCONNECT function SQLIDLEDISCONNECT function Similar behavior to implicit disconnect based Similar behavior to implicit disconnect based

on IdleTimeOut property, now it can be done on IdleTimeOut property, now it can be done explicitly.explicitly.

The function fails if statement handle is busy or The function fails if statement handle is busy or connection is in manual commit mode.connection is in manual commit mode.

OLEDB ProviderOLEDB Provider

Return Rowset from a stored Return Rowset from a stored procedure.procedure. SetResultSet / GetResultSet / SetResultSet / GetResultSet /

ClearResultSetClearResultSet When used in native VFP, return When used in native VFP, return

value is the alias of the returned value is the alias of the returned rowset.rowset.

CursorAdapterCursorAdapter

Support for TIMESTAMP fieldsSupport for TIMESTAMP fields TimestampFieldListTimestampFieldList

Auto-refresh supportAuto-refresh support On demand record refreshOn demand record refresh

ca.RecordRefresh([nRecords],[nRecordOffset]) ca.RecordRefresh([nRecords],[nRecordOffset]) Delayed Memo fetch Delayed Memo fetch DEFAULT and CHECK constraints DEFAULT and CHECK constraints MapVarChar / MapBinaryMapVarChar / MapBinary

XMLAdapterXMLAdapter

Support for hierarchical XMLSupport for hierarchical XML Support for XPath expressions.Support for XPath expressions. XML encoding/decoding XML encoding/decoding

enhancementsenhancements

RecommendationRecommendation

Taming Visual FoxPro‘s SQLTaming Visual FoxPro‘s SQLReal World Data Solutions For VFPReal World Data Solutions For VFPTamar E. Granor with Della MartinTamar E. Granor with Della MartinHentzenwerke PublishingHentzenwerke Publishing

Special offer 20 EURO for mass orderSpecial offer 20 EURO for mass orderbut only if you are interested…but only if you are interested…