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#41
 
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Re: About grammar and syntax on a possible relational language -
03-12-2008
, 10:29 AM
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On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. *I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. *For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. *The input of the media layer is necessarily a relation. *The input of the logical layer may either be a relation or an attribute set. |
The example that introduced the confusion for me is this:
[MAKE VIP_MEMBER = {RICH_EMPLOYEE}]
where "RICH_EMPLOYEE" refers to a relation.
TroyK
#42
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On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. *I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. *For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. *The input of the media layer is necessarily a relation. *The input of the logical layer may either be a relation or an attribute set. |
The example that introduced the confusion for me is this:
[MAKE VIP_MEMBER = {RICH_EMPLOYEE}]
where "RICH_EMPLOYEE" refers to a relation.
TroyK
#43
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On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. *I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. *For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. *The input of the media layer is necessarily a relation. *The input of the logical layer may either be a relation or an attribute set. |
The example that introduced the confusion for me is this:
[MAKE VIP_MEMBER = {RICH_EMPLOYEE}]
where "RICH_EMPLOYEE" refers to a relation.
TroyK
#44
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On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. *I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. *For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. *The input of the media layer is necessarily a relation. *The input of the logical layer may either be a relation or an attribute set. |
The example that introduced the confusion for me is this:
[MAKE VIP_MEMBER = {RICH_EMPLOYEE}]
where "RICH_EMPLOYEE" refers to a relation.
TroyK
#45
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On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. *I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. *For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. *The input of the media layer is necessarily a relation. *The input of the logical layer may either be a relation or an attribute set. |
The example that introduced the confusion for me is this:
[MAKE VIP_MEMBER = {RICH_EMPLOYEE}]
where "RICH_EMPLOYEE" refers to a relation.
TroyK
#46
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On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. *I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. *For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. *The input of the media layer is necessarily a relation. *The input of the logical layer may either be a relation or an attribute set. |
The example that introduced the confusion for me is this:
[MAKE VIP_MEMBER = {RICH_EMPLOYEE}]
where "RICH_EMPLOYEE" refers to a relation.
TroyK
#47
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On Mar 12, 8:33 am, Cimode <cim... (AT) hotmail (DOT) com> wrote: On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. The input of the media layer is necessarily a relation. The input of the logical layer may either be a relation or an attribute set. I see what you're aiming for and I think that I agree with the syntax. The example that introduced the confusion for me is this: [MAKE VIP_MEMBER = {RICH_EMPLOYEE}] where "RICH_EMPLOYEE" refers to a relation. Yes, under this premise a relation is a synonym for type. |
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TroyK |
#48
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On Mar 12, 8:33 am, Cimode <cim... (AT) hotmail (DOT) com> wrote: On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. The input of the media layer is necessarily a relation. The input of the logical layer may either be a relation or an attribute set. I see what you're aiming for and I think that I agree with the syntax. The example that introduced the confusion for me is this: [MAKE VIP_MEMBER = {RICH_EMPLOYEE}] where "RICH_EMPLOYEE" refers to a relation. Yes, under this premise a relation is a synonym for type. |
Quote:
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TroyK |
#49
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On Mar 12, 8:33 am, Cimode <cim... (AT) hotmail (DOT) com> wrote: On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. The input of the media layer is necessarily a relation. The input of the logical layer may either be a relation or an attribute set. I see what you're aiming for and I think that I agree with the syntax. The example that introduced the confusion for me is this: [MAKE VIP_MEMBER = {RICH_EMPLOYEE}] where "RICH_EMPLOYEE" refers to a relation. Yes, under this premise a relation is a synonym for type. |
Quote:
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TroyK |
#50
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On Mar 12, 8:33 am, Cimode <cim... (AT) hotmail (DOT) com> wrote: On Mar 11, 5:38 pm, Cimode <cim... (AT) hotmail (DOT) com> wrote: Why not: [MAKE RICH_EMPLOYEE = {EMPLOYEE WITH SALARY > 100000}] (with curly braces around the derivation expression)? It seems a little "off" to use them only sometimes. Because I reserved '[]' to relation operation and '{}' to relation definition. I will keep the remark in mind though To be more explicit {} is attribute level manipulation and [] is relation level manipulation to keep the language as versatile as possible. For example [MAKE R0 = {ATTRIBUTE0_1, ATTRIBUTE0_2}] [MAKE R1 = {ATTRIBUTE1_1, ATTRIBUTE1_2}] [MAKE R2 = R0 UNION R1] PRESENT2D [R2] does the same thing as PRESENT2D [{ATTRIBUTE0_1, ATTRIBUTE0_2} UNION {ATTRIBUTE1_1, ATTRIBUTE1_2}] It is also about the coherence of the computing model behind. The input of the media layer is necessarily a relation. The input of the logical layer may either be a relation or an attribute set. I see what you're aiming for and I think that I agree with the syntax. The example that introduced the confusion for me is this: [MAKE VIP_MEMBER = {RICH_EMPLOYEE}] where "RICH_EMPLOYEE" refers to a relation. Yes, under this premise a relation is a synonym for type. |
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TroyK |
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