Difference: ADQL-2_0-Err-2 (1 vs. 10)

ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Author: Dave Morris

Date last changed: 2018-02-14

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

Considering what current TAP-1.0 services using ADQL implement and the usual SQL definition of the modulo operator:

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

This erratum changes the description of the mod, rand, round and truncate function in Table 1 on page 8 of the ADQL-2.0 recommendation from

mod(x, y)
    Returns the remainder of y/x.
rand(x)
    Returns a random value between 0.0 and 1.0, where x is a seed value.
round(x, n)
    Rounds double value x to n number of decimal places, with the default
    being to round to the nearest integer. To round to the left of the decimal 
    point, a negative number should be provided.
truncate(x, n)
    Returns the result of truncating the argument x to n decimal places.

to

mod(x, y)
    Returns the remainder of x/y.
rand(x)
    Returns a random value between 0.0 and 1.0.  The optional argument,
    originally intended to provide a random seed, has undefined semantics.
    Query writers are advised to use the form without the argument.
round(x, n)
    Rounds double value x to n number of decimal places, with the default
    being to round to the nearest integer. To round to the left of the decimal 
    point, a negative number should be provided. The integer n is optional
    and its value should default to 0.
truncate(x, n)
    Returns the result of truncating the argument x to n decimal places.
    The integer n is optional and its value should default to 0.

Impact Assessment

The changes proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services show they already act following the behaviour here above described for the modulo function, while for the remaining 3 issues, all of them simply require some explicit wording in the description to follow the grammar constraints. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same behaviour too. See the mail threads referenced in the introduction of this page for details.

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ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

Considering what current TAP-1.0 services using ADQL implement and the usual SQL definition of the modulo operator:

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

This erratum changes the description of the mod, rand, round and truncate function in Table 1 on page 8 of the ADQL-2.0 recommendation from

mod(x, y)
    Returns the remainder of y/x.
rand(x)
    Returns a random value between 0.0 and 1.0, where x is a seed value.
round(x, n)
    Rounds double value x to n number of decimal places, with the default
    being to round to the nearest integer. To round to the left of the decimal 
    point, a negative number should be provided.
truncate(x, n)
    Returns the result of truncating the argument x to n decimal places.

to

mod(x, y)
    Returns the remainder of x/y.
rand(x)
    Returns a random value between 0.0 and 1.0.  The optional argument,
    originally intended to provide a random seed, has undefined semantics.
    Query writers are advised to use the form without the argument.
round(x, n)
    Rounds double value x to n number of decimal places, with the default
    being to round to the nearest integer. To round to the left of the decimal 
    point, a negative number should be provided. The integer n is optional
    and its value should default to 0.
truncate(x, n)
    Returns the result of truncating the argument x to n decimal places.
    The integer n is optional and its value should default to 0.

Impact Assessment

The changes proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services show they already act following the behaviour here above described for the modulo function, while for the remaining 3 issues, all of them simply require some explicit wording in the description to follow the grammar constraints. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same behaviour too. See the mail threads referenced in the introduction of this page for details.

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 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
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ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Author: DAL WG

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

Considering what current TAP-1.0 services using ADQL implement and the usual SQL definition of the modulo operator:

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

Impact Assessment

The changes proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services show they already act following the behaviour here above described for the modulo function, while for the remaining 3 issues, all of them simply require some explicit wording in the description to follow the grammar constraints. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same behaviour too. See the mail threads referenced in the introduction of this page for details.

<-- 

 

 

 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
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ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Author: DAL WG

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

Table 1 on page 8 of the ADQL-2.0 recommendation reports the following descriptions for the hereby discussed mathematical functions:

mod(x, y)

Returns the remainder of y/x.

rand(x)

Returns a random value between 0.0 and 1.0, where x is a seed value.

round(x, n)

Rounds double value x to n number of decimal places, with the default being to round to the nearest integer. To round to the left of the decimal point, a negative number should be provided.

truncate(x, n)

Returns the result of truncating the argument x to n decimal places.

This erratum amends these descriptions, given what's discussed in the rationale of this erratum, substituting them with the following ones:

mod(x, y)

Returns the remainder of x/y.

rand(x)

Returns a random value between 0.0 and 1.0. The optional argument, originally intended to provide a random seed, has undefined semantics. Query writers are advised to use the form without the argument.

round(x, n)

Rounds double value x to n number of decimal places, with the default being to round to the nearest integer. To round to the left of the decimal point, a negative number should be provided. The integer n is optional and its value should default to 0.

truncate(x, n)

Returns the result of truncating the argument x to n decimal places. The integer n is optional and its value should default to 0.

Impact Assessment

The changes proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services show they already act following the behaviour here above described for the modulo function, while for the remaining 3 issues, all of them simply require some explicit wording in the description to follow the grammar constraints. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same behaviour too. See the mail threads referenced in the introduction of this page for details.

<-- 

 

 

 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
-->

ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Author: DAL WG

Date last changed: 2017-09-28

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

Considering what current TAP-1.0 services using ADQL and the mathematical description of the modulo operator where

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

Table 1 on page 8 of the ADQL-2.0 recommendation reports the following descriptions for the hereby discussed mathematical functions:

mod(x, y)

Returns the remainder of y/x.

rand(x)

Returns a random value between 0.0 and 1.0, where x is a seed value.

round(x, n)

Rounds double value x to n number of decimal places, with the default being to round to the nearest integer. To round to the left of the decimal point, a negative number should be provided.

truncate(x, n)

Returns the result of truncating the argument x to n decimal places.

This erratum amends these descriptions, given what's discussed in the rationale of this erratum, substituting them with the following ones:

mod(x, y)

Returns the remainder of x/y.

rand(x)

Returns a random value between 0.0 and 1.0. The optional argument, originally intended to provide a random seed, has undefined semantics. Query writers are advised to use the form without the argument.

round(x, n)

Rounds double value x to n number of decimal places, with the default being to round to the nearest integer. To round to the left of the decimal point, a negative number should be provided. The integer n is optional and its value should default to 0.

truncate(x, n)

Returns the result of truncating the argument x to n decimal places. The integer n is optional and its value should default to 0.

Impact Assessment

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 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
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ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Author: DAL WG

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

Considering what current TAP-1.0 services using ADQL and the mathematical description of the modulo operator where

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

Table 1 on page 8 of the ADQL-2.0 recommendation reports the following descriptions for the hereby discussed mathematical functions:

mod(x, y)

Returns the remainder of y/x.

rand(x)

Returns a random value between 0.0 and 1.0, where x is a seed value.

round(x, n)

Rounds double value x to n number of decimal places, with the default being to round to the nearest integer. To round to the left of the decimal point, a negative number should be provided.

truncate(x, n)

Returns the result of truncating the argument x to n decimal places.

This erratum amends these descriptions, given what's discussed in the rationale of this erratum, substituting them with the following ones:

mod(x, y)

Returns the remainder of x/y.

round(x, n)

Rounds double value x to n number of decimal places, with the default being to round to the nearest integer. To round to the left of the decimal point, a negative number should be provided. The integer n is optional and its value should default to 0.

truncate(x, n)

Returns the result of truncating the argument x to n decimal places. The integer n is optional and its value should default to 0.

Impact Assessment

The changes proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services show they already act following the behaviour here above described for the modulo function, while for the remaining 3 issue, all of them simply require some explicit wording in the description to follow the grammar constrains. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same behaviour too. See the mail threads referenced in the introduction of this page for details.

<-- 

 

 

 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
-->

ADQL-2.0 Erratum 2: Mathematical Functions' Table issues

Author: DAL WG

Date last changed: 2017-05-26

Rationale

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function. Discussion went on also on this other thread.

Subsequently a different thread highlighted other mismatches between Table 1 (Mathematical functions) descriptions and the ADQL-2.0 grammar.

Here follows what emerged as possible erratum content from those discussions.

MOD function description

Considering what current TAP-1.0 services using ADQL and the mathematical description of the modulo operator where

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

RAND optional seed

ADQL BNF grammar (page 29 of ADQL-2.0) reports the unsigned_integer x to be an optional argument (the seed) to the random mathematical function. This is not made explicit in the description in Table 1.

We suggest to amend the description changing the final "where x is a seed" into "where x is an optional seed" value.

ROUND optional places number

ADQL BNF grammar (pages 29-30 of ADQL-2.0) reports the signed_integer n of ROUND(x, n) to be an optional argument. This signed integer number of places to round the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of round(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

TRUNCATE optional places number

ADQL BNF grammar (page 30 of ADQL-2.0) reports the signed_integer n of TRUNCATE(x, n) to be an optional argument. This signed integer number of places to truncate the value of x to is not made explicit to be optional in Table 1 description. Also, as per SQL standard, it should default to 0 when not explicitly present.

We suggest to amend the description of truncate(x, n) in Table 1 by adding a final sentence reading "The integer n is optional and its value should default to 0.".

Erratum Content

Table 1 on page 8 of the ADQL-2.0 recommendation reports the following descriptions for the hereby discussed mathematical functions:

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with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

Impact Assesment

The changes proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services show they already act following the behaviour here above described for the modulo function, while for the remaining 3 issue, all of them simply require some explicit wording in the description to follow the grammar constrains. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same behaviour too. See the mail threads referenced in the introduction of this page for details.

<-- 

 

 

 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
-->

Erratum Content

Table 1 on page 8 of the ADQL-2.0 recommendation reports

Rationale

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

The definition of mod(x, y) in ADQL-2.0 should be amended to "Returns the remainder of x/y". It should also be made clear, maybe in a future revision, to follow the above rules for the remainder and its sign.

Impact Assesment

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 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
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ADQL-2.0 Erratum 2 - MOD function description

IVOA DAL mailing list thread on July 2016 highlighted a possible issue with the description of the MOD function.

Erratum Content

Table 1 on page 8 of the ADQL-2.0 recommendation reports

Rationale

Considering what current TAP services using ADQL and the mathematical description of the modulo operator where

M % N = R

with

• R having the same sign as M
• |R| is less than |N|
• M = K * N + R for a given integer K

The definition of mod(x, y) in ADQL-2.0 should be amended to "Returns the remainder of x/y". It should also be made clear, maybe in a future revision, to follow the above rules for the remainder and its sign.

Impact Assesment

The change proposed by this erratum should impact no existing IVOA resource. Checks against the major TAP services shows they already act following the behaviour here above described. Checks against a choice of RDBMS-es (PostgreSQL, MySQL, MariaDB, Apache Derby, HyperSQL and Oracle) shows the same bahaviour too. See the mail thread referenced in the introduction of this page for details.

<-- 

 

 

 Set ALLOWTOPICRENAME = TWikiAdminGroup
 
 
-->