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XQuery Developer's Guide

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XQuery-SQL Mapping Reference

This appendix provides the details of BEA AquaLogic Data Services Platform (DSP) core support and base support for relational data, and includes these topics:

Each section that follows includes information about:

 


IBM DB2/NT 8

The tables in this section identify all data type and other mappings that the XQuery engine generates or supports for IBM DB2/NT 8.

Data Type Mapping

The following table lists supported data type mappings.

Table B-1 Data Type Mappings

DB2 Data Type

XQuery Type

BIGINT

xs:long

BLOB

xs:hexBinary

CHAR

xs:string

CHAR() FOR BIT DATA

xs:hexBinary

CLOB1

xs:string

DATE

xs:date

DOUBLE

xs:double

DECIMAL(p,s)2 (NUMERIC)

xs:decimal (if s > 0), xs:integer (if s = 0)

INTEGER

xs:int

LONG VARCHAR1

xs:string

LONG VARCHAR FOR BIT DATA

xs:hexBinary

REAL

xs:float

SMALLINT

xs:short

TIME3

xs:time4

TIMESTAMP5

xs:dateTime4

VARCHAR

xs:string4

VARCHAR() FOR BIT DATA

xs:hexBinary


1. Pushed down in project list only.


2. Where p is precision (total number of digits, both to the right and left of decimal point) and s is scale (total number of digits to the right of decimal point).


3. Accurate to 1 second.


4. Values converted to local time zone (timezone information removed) due to TIME and TIMESTAMP limitations. See Date and Time Data Type Differences: Timezones and Time Precision for more information.


5. Precision limited to milliseconds.

Function and Operator Pushdown

The following table lists functions and operators that are pushed down to IBM DB2/NT8 RDBMSs. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-2 Functions and Operators

Group

Functions and operators

Logical operators

and, or, not

Numeric arithmetic

+, -, *, div, idiv1

mod2

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

Numeric functions

abs, ceiling, floor, round

String comparisons3

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

concat, upper-case, lower-case, substring(2,3)4, string-length, contains5, starts-with5, ends-with5, fn-bea:sql-like(2,3) fn-bea:trim6, fn-bea:trim-left6, fn-bea:trim-right6

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xs:time

Datetime functions

year-from-dateTime, year-from-date, month-from-dateTime, month-from-date, day-from-dateTime, day-from-date, hours-from-dateTime, hours-from-time, minutes-from-dateTime, minutes-from-time, seconds-from-dateTime, seconds-from-time, fn-bea:date-from-dateTime, fn-bea:time-from-dateTime

Aggregate

min, max, sum, avg, count, count(distinct-values)

Other

empty, exists, subsequence7


1. All numeric types.


2. xs:integer (and subtypes) only.


3. Arguments must have SQL data type CHAR or VARCHAR.


4. If second and third arguments are types xs:double or xs:float, they cannot be parameters.


5. Second argument must be a constant or a parameter.


6. Argument must be SQL data type CHAR or VARCHAR.


7. Both two- and three-argument variants supported, with the restriction that no pushdown occurs when $startingLoc or $length are typed as xs:double.

Cast Operation Pushdown

The following table lists supported cast operations.

Table B-3 Cast Operations

Source XQuery Type

Target XQuery Type

numeric

xs:double

numeric

xs:float

numeric

xs:int

numeric

xs:integer

numeric

xs:short

xs:decimal (and subtypes)

xs:string

xs:integer (and subtypes)

xs:decimal

xs:string

xs:double

xs:string

xs:float

xs:string

xs:int

xs:string

xs:integer

xs:string

xs:short

xs:dateTime

xs:time

Other SQL Generation Capabilities

The following table lists common query patterns that can be pushed down. See Common Query Patterns for details.

Table B-4 Other SQL Generation Capabilities

Feature

Description

If-then-else

yes

Inner joins

yes, SQL-92 syntax

Outer joins

yes, SQL-92 syntax

Semi joins, Anti semi joins

yes

Order by

yes

Order by: Empty (NULL) order supported

Fixed (always sorts NULLs high). Order-bys with "empty least" modifier (the XQuery default) are not pushed down.

Order by: Aggregate function in ordering expression

yes

Group by

yes

Distinct pattern

yes

Trivial aggregate pattern

yes (using GROUP BY constant)

Direct SQL composition

yes

 


Microsoft SQL Server 2000

The tables in this section identify all data type and other mappings that the XQuery engine generates or supports for Microsoft SQL Server 2000.

Data Type Mapping

The following table lists supported data type mappings for Microsoft SQL Server 2000.

Table B-5 Data Type Mapping

SQL Data Type

XQuery Type

BIGINT

xs:long

BINARY

xs:hexBinary

BIT

xs:boolean

CHAR

xs:string

DATETIME1

xs:dateTime2

DECIMAL(p,s)3 (NUMERIC)

xs:decimal (if s > 0), xs:integer (if s = 0)

FLOAT

xs:double

IMAGE

xs:hexBinary

INTEGER

xs:int

MONEY

xs:decimal

NCHAR

xs:string

NTEXT4

xs:string

NVARCHAR

xs:string

REAL

xs:float

SMALLDATETIME5

xs:dateTime

SMALLINT

xs:short

SMALLMONEY

xs:decimal

SQL_VARIANT

xs:string

TEXT4

xs:string

TIMESTAMP

xs:hexBinary

TINYINT

xs:short

VARBINARY

xs:hexBinary

VARCHAR

xs:string

UNIQUIDENTIFIER

xs:string


1. Fractional-second-precision up to 3 digits (milliseconds). No timezone.


2. Values converted to local time zone (timezone information removed) and fractional seconds truncated to milliseconds due to DATETIME limitations. See Date and Time Data Type Differences: Timezones and Time Precision for more information.


3. Where p is precision (total number of digits, both to the right and left of decimal point) and s is scale (total number of digits to the right of decimal point).


4. Pushed down in project list only.


5. Accuracy of 1 minute.

Additionally, the following XQuery data types can be passed as parameters or returned by pushed functions:

Function and Operator Pushdown

The following table lists functions and operators that are pushed down to Microsoft SQL Server 2000. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-6 Function and Operator Pushdown

Group

Functions and Operators

Logical operators

and, or, not

Numeric arithmetic

+, -, *, div, idiv1

mod2

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

Numeric functions

abs, ceiling, floor, round

String comparisons3

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

concat, upper-case, lower-case, substring(2,3)4, string-length, contains5, starts-with5, ends-with5, fn-bea:sql-like(2,3)4, fn-bea:trim, fn-bea:trim-left, fn-bea:trim-right

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xdt:yearMonthDuration, xdt:dayTimeDuration

Datetime functions

year-from-dateTime, year-from-date, years-from-duration, month-from-dateTime, month-from-date, months-from-duration, day-from-dateTime, day-from-date, days-from-duration, hours-from-dateTime, hours-from-duration, minutes-from-dateTime, minutes-from-duration, seconds-from-dateTime, seconds-from-duration, fn-bea:date-from-dateTime

Datetime arithmetic

op:add-yearMonthDurations, op:add-dayTimeDurations, op:subtract-yearMonthDurations, op:subtract-dayTimeDurations, op:multiply-yearMonthDuration, op:multiply-dayTimeDuration, op:divide-yearMonthDuration, op:divide-dayTimeDuration, subtract-dateTimes-yielding-yearMonthDuration, subtract-dateTimes-yielding-dayTimeDuration, op:add-yearMonthDuration-to-dateTime, op:add-dayTimeDuration-to-dateTime, op:subtract-yearMonthDuration-from-dateTime, op:subtract-dayTimeDuration-from-dateTime, subtract-dates-yielding-yearMonthDuration, subtract-dates-yielding-dayTimeDuration, op:add-yearMonthDuration-to-date, op:add-dayTimeDuration-to-date, op:subtract-yearMonthDuration-from-date, op:subtract-dayTimeDuration-from-date

Aggregate

min, max, sum, avg, count, count(distinct-values)

Other

empty, exists, subsequence6


1. For all numeric types


2. For xs:integer and its subtypes only.


3. Arguments must be of SQL data type CHAR, NCHAR, VARCHAR, or NVARCHAR.


4. Both the 2-argument and 3-argument versions of function supported.


5. Second argument must be SQL data type CHAR, NCHAR, VARCHAR, or NVARCHAR.


6. Only the three-argument variant of fn:subsequence is supported, with the additionl requirement that the $startingLoc must be 1 (constant) and $length must be xs:integer type.

Cast Operation Pushdown

The following table lists supported cast operations.

Table B-7 Cast Operations

Source XQuery Data Type

Target XQuery Data Type

numeric

xs:string

numeric

xs:double

numeric

xs:float

numeric

xs:integer

numeric

xs:long

numeric

xs:int

numeric

xs:short

xs:integer (and subtypes)

xs:decimal

xs:string

xs:double1

xs:string

xs:float

xs:string

xs:integer

xs:string

xs:long

xs:string

xs:int

xs:string

xs:short

xs:dateTime

xs:date

xs:dateTime

xs:string


1. Source SQL type must be CHAR, NCHAR, VARCHAR, or NVARCHAR.

Other SQL Generation Capabilities

The following table lists common query patterns that can be pushed down. See Common Query Patterns for details.

Table B-8 Other SQL Generation Capabilities

Feature

Description

If-then-else

yes

Inner joins

yes, SQL-92 syntax

Outer joins

yes, SQL-92 syntax

Semi joins, Anti semi joins

yes

Order by

yes

Order by: Empty order (NULL order)

fixed (always sorts NULLs low). Order-bys with "empty greatest" modifier are not pushed down.

Order by: Aggregate function in ordering expression

yes

Group by

yes

Distinct pattern

yes

Trivial aggregate pattern

yes (using subquery)

Direct SQL composition

yes

 


Oracle 8.1.x

The tables in this section identify all data type and other mappings that the XQuery engine generates or supports for Oracle 8.1.x (Oracle 8i).

 


Data Type Mapping

Table B-9 Data Type Mapping

Oracle 8 Data Type

XQuery Type

BFILE

not supported

BLOB

xs:hexBinary

CHAR

xs:string

CLOB1

xs:string

DATE2

xs:dateTime

FLOAT

xs:double

LONG1

xs:string

LONG RAW

xs:hexBinary

NCHAR

xs:string

NCLOB1

xs:string

NUMBER

xs:double

NUMBER(p,s)3

xs:decimal (if s > 0), xs:integer (if s <=0)

NVARCHAR2

xs:string

RAW

xs:hexBinary

ROWID

xs:string

UROWID

xs:string


1. Pushed down in project list only.


2. Does not support fractional seconds.


3. Where p is precision (total number of digits, both to the right and left of decimal point) and s is scale (total number of digits to the right of decimal point).

Additionally, the following XQuery data types can be passed as parameters or returned by pushed functions:

Function and Operator Pushdown

The following table lists functions and operators that are pushed down. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-10 Function and Operator Pushdown

Group

Functions and operators

Logical operators

and, or, not

Numeric arithmetic1

+, -, *, div, idiv, mod

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

Numeric functions

abs, ceiling, floor, round

String comparisons2

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

concat, upper-case3, lower-case3, substring(2,3)3, string-length4, contains5, starts-with5, ends-with5, fn-bea:sql-like(2,3), fn-bea:trim, fn-bea:trim-left, fn-bea:trim-right

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xdt:yearMonthDuration

Datetime functions

year-from-dateTime, year-from-date, years-from-duration, month-from-dateTime, month-from-date, months-from-duration, day-from-dateTime, day-from-date, days-from-duration, hours-from-dateTime, minutes-from-dateTime, seconds-from-dateTime, fn-bea:date-from-dateTime

Datetime arithmetic

op:add-yearMonthDurations, op:subtract-yearMonthDurations, op:multiply-yearMonthDuration, op:divide-yearMonthDuration, subtract-dateTimes-yielding-yearMonthDuration, op:add-yearMonthDuration-to-dateTime, op:subtract-yearMonthDuration-from-dateTime, subtract-dates-yielding-yearMonthDuration, op:add-yearMonthDuration-to-date, op:subtract-yearMonthDuration-from-date

Aggregate

min, max, sum, avg, count, count(distinct-values)

Other

empty, exists, subsequence6


1. For all numeric types.


2. Arguments must be of SQL data type CHAR, NCHAR, NVARCHAR2, or VARCHAR2.


3. Empty input (NULL) handling deviates from XQuery semantics—returns empty sequence (instead of empty string).


4. Argument must be data type CHAR, NCHAR, NVARCHAR2, or VARCHAR2.


5. Second argument must be data type CHAR, NCHAR, NVARCHAR2, or VARCHAR2.


6. Both two- and three-argument variants of fn:subsequence() are supported without restriction.

Cast Operation Pushdown

The followingtable lists supported cast operations.

Table B-11 Cast Operation Pushdown

Source XQuery Type

Target XQuery Type

numeric

xs:string

numeric

xs:decimal

numeric

xs:integer

numeric

xs:float

numeric

xs:double

xs:string

xs:decimal1

xs:string

xs:integer1

xs:string

xs:float1

xs:string

xs:double1

xs:dateTime

xs:date

xs:date

xs:dateTime


1. Source data type must be CHAR, NCHAR, NVARCHAR2, or VARCHAR2.

Other SQL Generation Capabilities

The following table lists common query patterns that can be pushed down. See Common Query Patterns for details.

Table B-12 Other SQL Generation Capabilities

Feature

Description

If-then-else

yes

Inner joins

yes, SQL-89 syntax

Outer joins

yes, Oracle proprietary syntax

Semi joins, Anti semi joins

yes

Order by

yes

Order by: Empty order (NULL order)

dynamic, no restriction on order by pushdown

Order by: Aggregate function in ordering expression

yes

Group by

yes

Distinct pattern

yes

Trivial aggregate pattern

yes (using GROUP BY constant)

Direct SQL composition

yes

 


Oracle 9.x, 10.x

The tables in this section identify all data type and other mappings that the XQuery engine generates or supports for Oracle 9.x (Oracle 9i) and Oracle 10.x (Oracle 10g). Note that Oracle treats empty strings as NULLs, which deviates from XQuery semantics and may lead to unexpected results for expressions that are pushed down.

Data Type Mapping

Table B-13 Data Type Mapping

Oracle 9 Data Type

XQuery Type

BFILE

not supported

BLOB

xs:hexBinary

CHAR

xs:string

CLOB1

xs:string

DATE

xs:dateTime2

FLOAT

xs:double

INTERVAL DAY TO SECOND

xdt:dayTimeDuration

INTERVAL YEAR TO MONTH

xdt:yearMonthDuration

LONG1

xs:string

LONG RAW

xs:hexBinary

NCHAR

xs:string

NCLOB1

xs:string

NUMBER

xs:double

NUMBER(p,s)

xs:decimal (if s > 0), xs:integer (if s <=0)

NVARCHAR2

xs:string

RAW

xs:hexBinary

ROWID

xs:string

TIMESTAMP

xs:dateTime3

TIMESTAMP WITH LOCAL TIMEZONE

xs:dateTime

TIMESTAMP WITH TIMEZONE

xs:dateTime

VARCHAR2

xs:string

UROWID

xs:string


1. Pushed down in project list only.


2. When SDO stores xs:dateTime value in Oracle DATE type, it is converted to local time zone and fractional seconds are truncated due to DATE limitations. See Date and Time Data Type Differences: Timezones and Time Precision for more information.


3. XQuery engine maps XQuery xs:dateTime to either TIMESTAMP or TIMESTAMP WITH TIMEZONE data type, depending on presence of timezone information. Storing xs:dateTime using SDO may result in loss of precision for fractional seconds, depending on the SQL type definition.

Additionally, these XQuery data types can be passed as parameters or returned by pushed functions:

Function and Operator Pushdown

The following table lists functions and operators that are pushed down to Oracle 9.x and 10.x. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-14 Function and Operator Pushdown

Group

Functions and Operators

Logical operators

and, or, not

Numeric arithmetic1

+, -, *, div, idiv, mod

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

Numeric functions

abs, ceiling, floor, round

String comparisons2

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

concat, upper-case3, lower-case3, substring(2,3)3, string-length4, contains5, starts-with5, ends-with5, fn-bea:sql-like(2,3), fn-bea:trim, fn-bea:trim-left, fn-bea:trim-right

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xdt:yearMonthDuration, xdt:dayTimeDuration

Datetime functions

year-from-dateTime, year-from-date, years-from-duration, month-from-dateTime, month-from-date, months-from-duration, day-from-dateTime, day-from-date, days-from-duration, hours-from-dateTime, hours-from-duration, minutes-from-dateTime, minutes-from-duration, seconds-from-dateTime, seconds-from-duration, fn-bea:date-from-dateTime

Datetime arithmetic

op:add-yearMonthDurations, op:add-dayTimeDurations, op:subtract-yearMonthDurations, op:subtract-dayTimeDurations, op:multiply-yearMonthDuration, op:multiply-dayTimeDuration, op:divide-yearMonthDuration, op:divide-dayTimeDuration, subtract-dateTimes-yielding-yearMonthDuration, subtract-dateTimes-yielding-dayTimeDuration, op:add-yearMonthDuration-to-dateTime, op:add-dayTimeDuration-to-dateTime, op:subtract-yearMonthDuration-from-dateTime, op:subtract-dayTimeDuration-from-dateTime, subtract-dates-yielding-yearMonthDuration, subtract-dates-yielding-dayTimeDuration, op:add-yearMonthDuration-to-date, op:add-dayTimeDuration-to-date, op:subtract-yearMonthDuration-from-date, op:subtract-dayTimeDuration-from-date

Aggregate

min, max, sum, avg, count, count(distinct-values)

Other

empty, exists, subsequence6


1. For all numeric types


2. Arguments must be of SQL type (N)CHAR or (N)VARCHAR2


3. Empty input (NULL) handling deviates from XQuery semantics—returns empty sequence (instead of empty string).


4. Argument must be CHAR, CLOB, NCHAR, NVARCHAR2, or VARCHAR2 data type.


5. Second argument must be CHAR, NCHAR, NVARCHAR2, or VARCHAR2 data type.


6. Both two- and three-argument variants of fn:subsequence() are supported without restriction.

Cast Operation Pushdown

The following table lists cast operations that can be pushed down.

Table B-15 Cast Operation

Source XQuery Type

Target XQuery Type

numeric

xs:string

numeric

xs:decimal

numeric

xs:integer

numeric

xs:float

numeric

xs:double

xs:string

xs:decimal1

xs:string

xs:integer

xs:string

xs:float

xs:string

xs:double

xs:dateTime

xs:date

xs:date

xs:dateTime2


1. Source SQL type must be CHAR, NCHAR, VARCHAR2, or NVARCHAR2.


2. Source SQL type must be DATE or TIMESTAMP to achieve this mapping.

Other SQL Generation Capabilities

The following table lists common query patterns that can be pushed down. See Common Query Patterns for details.

Table B-16 Other SQL Generation Capabilities

Feature

Description

If-then-else

yes

Inner joins

yes, SQL-92 syntax

Outer joins

yes, SQL-92 syntax

Semi joins, Anti semi joins

yes

Order by

yes

Order by: Empty order (NULL order)

dynamic, no restriction on order by pushdown

Order by: Aggregate function in ordering expression

yes

Group by

yes

Distinct pattern

yes

Trivial aggregate pattern pushdown

yes (using GROUP BY constant)

Direct SQL composition

yes

 


Pointbase 4.4 (and higher)

The tables in this section identify all data type and other mappings that the XQuery engine generates or supports for Pointbase.

Data Type Mapping

Table B-17 Data Type Mapping

Pointbase Data Type

XQuery Type

BIGINT

xs:long

BLOB

xs:hexBinary

BOOLEAN

xs:boolean

CHAR (CHARACTER)

xs:string

CLOB

xs:string

DATE

xs:date

DECIMAL(p,s)1 (NUMERIC)

xs:decimal (if s > 0), xs:integer (if s == 0)

DOUBLE PRECISION

xs:double

FLOAT

xs:double

INTEGER (INT)

xs:int

SMALLINT

xs:short

REAL

xs:float

TIME

xs:time

TIMESTAMP

xs:dateTime

VARCHAR

xs:string


1. Where p is precision (total number of digits, both to the right and left of decimal point) and s is scale (total number of digits to the right of decimal point).

Function and Operator Pushdown

The following table lists functions and operators that are pushed down to Pointbase. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-18 Function and Operator Pushdown

Group

Functions and operators

Logical operators

and, or, not

Numeric arithmetic1

+, -, *, div, idiv

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String comparisons2

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

concat,upper-case, lower-case, substring(2,3), string-length, contains3, starts-with3, ends-with3, fn-bea:sql-like(2,3) fn-bea:trim, fn-bea:trim-left, fn-bea:trim-right

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xs:time

Datetime functions

year-from-dateTime, year-from-date, month-from-dateTime, month-from-date, day-from-dateTime, day-from-date, hours-from-dateTime, hours-from-time, minutes-from-dateTime, minutes-from-time, seconds-from-dateTime, seconds-from-time, fn-bea:date-from-dateTime

Aggregate

min, max, sum, avg, count, count(distinct-values)

Other

empty, exists


1. All numeric types


2. CHAR or VARCHAR SQL data types only for arguments


3. Second argument must be constant or parameter.

Cast Operation Pushdown

The following table lists supported cast operations.

Table B-19 Cast Operation Pushdown

Source XQuery Type

Target XQuery Type

numeric

xs:decimal

numeric

xs:double

numeric

xs:float

numeric

xs:int

numeric

xs:short

numeric

xs:string

xs:integer and its subtypes

xs:integer

xs:integer and its subtypes

xs:long

xs:string

xs:decimal1

xs:string

xs:double1

xs:string

xs:float1

xs:string

xs:integer1

xs:string

xs:long1

xs:string

xs:int1

xs:string

xs:short1

xs:dateTime

xs:date


1. Source SQL data type must be CHAR or VARCHAR

Other SQL Generation Capabilities

The following table lists common query patterns that can be pushed down. See Common Query Patterns for details.

Table B-20 Other SQL Generation Capabilities

Feature

Description

If-then-else

no

Inner joins

yes, SQL-92 syntax

Outer joins

yes (partially), SQL-92 syntax. Only simple outer joins are pushed, the ones that require subquery don't (e.g. when right branch has a where clause)

Semi joins, Anti semi joins

yes

Order by

yes

Order by: Empty order (NULL order)

fixed (always sorts NULLs low). Order-bys with "empty greatest" modifier are not pushed down.

Order by: Aggregate function in ordering expression

no

Group by

yes (Group by function expression is not supported, only group by column is pushed

Distinct pattern

yes

Trivial aggregate pattern pushdown

no

Direct SQL composition

no

 


Sybase 12.5.2 (and higher)

The tables in this section identify all data type and other mappings that the XQuery engine generates or supports for Sybase 12.5.2 (and higher).

As you read through the tables in this section, be aware that Sybase deviates from XQuery semantics (which ignores empty strings) and treats empty strings as a single-space string.

Data Type Mapping

This table defines all data type mappings supported.

Table B-21 Data Type Mapping

Sybase Data Type

XQuery Type

BINARY

xs:hexBinary

BIT

xs:boolean

CHAR

xs:string

DATE

xs:date

DATETIME1

xs:dateTime2

DECIMAL(p,s)3 (NUMERIC)

xs:decimal (if s > 0), xs:integer (if s == 0)

DOUBLE PRECISION

xs:double

FLOAT

xs:double

IMAGE

xs:hexBinary

INT (INTEGER)

xs:int

MONEY

xs:decimal

NCHAR

xs:string

NVARCHAR

xs:string

REAL

xs:float

SMALLDATETIME4

xs:dateTime

SMALLINT

xs:short

SMALLMONEY

xs:decimal

SYSNAME

xs:string

TEXT5

xs:string

TIME

xs:time

TINYINT

xs:short

VARBINARY

xs:hexBinary

VARCHAR

xs:string


1. Supports fractional seconds up to 3 digits (milliseconds) precision; no timezone information.


2. Values converted to local time zone (timezone information removed) and fractional seconds truncated to milliseconds due to DATETIME limitations. See Date and Time Data Type Differences: Timezones and Time Precision for more information.


3. Where p is precision (total number of digits, both to the right and left of decimal point) and s is scale (total number of digits to the right of decimal point).


4. Accurate to 1 minute.


5. Expressions returning text are pushed down in the project list only.

Additionally, the following data types can be passed as parameters or returned by pushed functions:

See "Datetime arithmetic" in Table  for details.

Function and Operator Pushdown

The following table lists functions and operators that are pushed down to base RDBMSs. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-22 Function and Operator Pushdown

Group

Functions and operators

Logical operators

and, or, not

Numeric arithmetic

+, -, *, div 1

idiv2

mod3

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

Numeric functions

abs, ceiling, floor, round

String comparisons4

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

concat5, upper-case, lower-case, substring(2,3), string-length, contains6, starts-with6, ends-with6, fn-bea:sql-like(2,3), fn-bea:trim, fn-bea:trim-left, fn-bea:trim-right

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xs:time, xdt:yearMonthDuration, xdt:dayTimeDuration

Datetime functions

year-from-dateTime, year-from-date, years-from-duration, month-from-dateTime, month-from-date, months-from-duration, day-from-dateTime, day-from-date, days-from-duration, hours-from-dateTime, hours-from-time, hours-from-duration, minutes-from-dateTime, minutes-from-time, minutes-from-duration, seconds-from-dateTime, seconds-from-time, seconds-from-duration, fn-bea:date-from-dateTime, fn-bea:time-from-dateTime

Datetime arithmetic

op:add-yearMonthDurations, op:subtract-yearMonthDurations, op:multiply-yearMonthDuration, op:divide-yearMonthDuration, op:add-dayTimeDurations, op:subtract-dayTimeDurations, op:multiply-dayTimeDuration, op:divide-dayTimeDuration, op:add-yearMonthDuration-to-dateTime, op:add-yearMonthDuration-to-date, op:subtract-yearMonthDuration-from-dateTime, op:subtract-yearMonthDuration-from-date, op:add-dayTimeDuration-to-dateTime, op:add-dayTimeDuration-to-date, op:subtract-dayTimeDuration-from-dateTime, op:subtract-dayTimeDuration-from-date, fn:subtract-dateTimes-yielding-yearMonthDuration, fn:subtract-dates-yielding-yearMonthDuration, fn:subtract-dateTimes-yielding-dayTimeDuration, fn:subtract-dates-yielding-dayTimeDuration

Aggregate

min, max, sum, avg, count, count(distinct-values)

Other

empty, exists


1. All numeric types (+, -, *, div operators are pushed down for all numeric types).


2. xs:decimal (and subtypes) only


3. xs:integer (and subtypes) only


4. Arguments must be SQL data type CHAR, NCHAR, NVARCHAR, or VARCHAR.


5. Each argument must be SQL data type CHAR, NCHAR, NVARCHAR, or VARCHAR.


6. Second argument must be constant or SQL parameter.

Cast Operation Pushdown

The following table lists supported cast operations.

Table B-23 Cast Operation Pushdown

Source XQuery Type

Target XQuery Type

numeric

xs:double

numeric

xs:float

numeric

xs:int

numeric

xs:short

numeric

xs:string

xs:decimal (and subtypes)

xs:integer

xs:integer (and subtypes)

xs:decimal

xs:string

xs:double1

xs:string

xs:float

xs:string

xs:int

xs:string

xs:integer

xs:string

xs:short

xs:dateTime

xs:date

xs:dateTime

xs:time


1. 

Source SQL type must be (N)CHAR or (N)VARCHAR

Other SQL Generation Capabilities

The following table lists common query patterns that can be pushed down. See Common Query Patterns for details.

Table B-24 Other SQL Generation Capabilities

Feature

Description

If-then-else

yes

Inner joins

yes, SQL-92 syntax

Outer joins

yes, SQL-92 syntax

Semi joins, Anti semi joins

yes

Order by

yes

Order by: Empty order (NULL order)

fixed (always sorts NULLs low). Order-bys with "empty greatest" modifier are not pushed down.

Order by: Aggregate function in ordering expression

yes

Group by

yes

Distinct pattern

yes

Trivial aggregate pattern

yes (using subquery)

Direct SQL composition

yes

 


Base (Generic) RDBMS Support

Each JDBC drivers provide information about inherent properties and capabilities of the RDBMS with which it is associated. During the metadata import process, DSP queries a configured data source's JDBC driver for basic properties and capabilities information. Much of the information obtained is stored in the metadata section of the data service definition file (.ds). See Understanding Data Services Platform Annotations for more information.

Database Capabilities Information

These database capabilities are obtained from the JDBC driver and stored as properties in the .ds (data service) definition file.

Table B-25 Database Properties for Capabilities

Property

Description

Possible Values

supportsSchemasInDataManipulation

Boolean that identifies whether SQL statements can include schema names

true, false

supportsCatalogsInDataManipulation

Boolean that identifies whether database catalogs can be addressed by SQL

true, false

supportsLikeEscapeClause

Boolean that identifies if the database supports ESCAPE clause in LIKE expression

true, false

nullSortOrder

Order in which NULLs are sorted

low, high, unknown

identifierQuote

String used as delimiter to denote (offset) identifier labels

String value (can be empty)

catalogSeparator

String used as delimiter (separator) between catalog (or schema) and table name

String value

The Data Services Platform XQuery engine typically quotes the names (identifiers) of object names to properly handle any special characters. The identifierQuote property (see Table ) is obtained from the JDBC driver. However, different RDBMSs may use different identifiers for different database object names:

If necessary, you can manually override the identifier quote property for each type of identifier (see Table ).

Typically, the identifierQuote property obtained from the JDBC driver is used. However, if the specific quote property is available and the RDBMS uses it, you can modify the annotation settings in the .ds file (see Relational Data Service Annotations for more information about these properties). The XQuery engine (metadata importer sub-system) uses the specific quote property (see Table ) if it is available, otherwise, it uses the "identifierQuote" property provided by the JDBC driver.

The only exception to this rule is for Sybase versions below Sybase 12.5.2, which is treated as a base platform. Sybase does not use quotes for catalogs even though JDBC drivers return double quote ('"') for "identifierQuote" property. The XQuery engine accommodates this mismatch by automatically setting "catalogQuote" property to the empty string.

Table B-26 Optional Quote Properties for Database Objects

Property

Description

Possible Values

catalogQuote

Special character used as quote to denote name of catalog

string

schemaQuote

Special character used as quote to denote name of schema

string

tableQuote

Special character used as quote to denote name of table

string

columnQuote

Special character used as quote to denote name of column

string

Data Type Mapping

When mapping SQL to XQuery datatypes, DSP XQuery engine first checks the JDBC typecode. If the typecode has a corresponding XQuery type, DSP uses the matching native type name. If no matching typecode or type name is available, the column is ignored.

Table B-27 Data Type Mapping (JDBC<->XQuery Equivalents)

JDBC Data Type

Typecode

XQuery Data Type

BIGINT

-5

xs:long

BINARY

-2

xs:string

BIT

-7

xs:boolean

BLOB

2004

xs:hexBinary

BOOLEAN

16

xs:boolean

CHAR

1

xs:string

CLOB1

2005

xs:string

DATE

91

xs:date2

DECIMAL (p,s)3

3

xs:decimal (if s > 0), xs:integer (if s =0)

DOUBLE

8

xs:double

FLOAT

6

xs:double

INTEGER

4

xs:int

LONGVARBINARY

-4

xs:hexBinary

LONGVARCHAR1

-1

xs:string

NUMERIC (p,s)3

2

xs:decimal (if s > 0), xs:integer (if s =0)

REAL

7

xs:float

SMALLINT

5

xs:short

TIME4

92

xs:time4

TIMESTAMP4

93

xs:dateTime2

TINYINT

-6

xs:short

VARBINARY

-3

xs:hexBinary

VARCHAR

12

xs:string

OTHER

1111

DSP uses native data type name to map to an appropriate XQuery data type.

Other vendor-specific JDBC type codes


1. Pushed down in project list only.


2. Values converted to local time zone (timezone information removed) due to DATE limitations. See Date and Time Data Type Differences: Timezones and Time Precision for more information.


3. Where p is precision (total number of digits, both to the right and left of decimal point) and s is scale (total number of digits to the right of decimal point).


4. Precision of underlying RDBMS determines the precision of TIME data type and how much truncation, if any, will occur in translating xs:time to TIME.

Function and Operator Pushdown

The following table lists functions and operators that are pushed down to base RDBMSs. See fn-bea:sql-like for details about two-argument and three-argument versions of the fn-bea:sql-like() function.

Table B-28

Group

Functions and Operators

Logical operators

and, or, not

Numeric arithmetic

+, -, *1

div2

Numeric comparisons1

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String comparisons3

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge

String functions

contains4, starts-with4, ends-with4, fn-bea:sql-like(2), fn-bea:sql-like(3),4 upper-case, lower-case

Datetime comparisons

=, !=, <, <=, >, >=, eq, ne, lt, le, gt, ge on xs:dateTime, xs:date, xs:time

Other

empty, exists


1. All numeric types


2. Support for xs:decimal, xs:float, and xs:double data types only.


3. Arguments must be CHAR or VARCHAR SQL data types.


4. First argument must be SQL data type CHAR or VARCHAR; second argument must be a constant or parameter; and RDBMS must support LIKE (with ESCAPE) clause.

Functions and Operators

Cast Operation Pushdown

For base RDBMS, cast operations are not pushed down.

Other SQL Generation Capabilities

The following table shows other SQL Pushdown capabilities, as discussed in Common Query Patterns.

Table B-29 SQL Generation Capabilities

Query

Supported

If-Then-Else

no

Inner joins

yes (SQL-89 syntax)

Outer joins

no

Semi-joins, Anti-semi-joins

no

Order by

yes

Order by: Empty (NULL) order supported

Database-dependent

Order by: Aggregate function in ordering expression

no

Group by

yes (by column only)

Distinct pattern

yes

Trivial aggregate pattern

no

Direct SQL composition

no

 

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