ch.()
Description:
Attach a computation to a channel and return the original channel.
Syntax:
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ch.(x) |
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ch.() |
Return the channel ch itself. |
Note:
The function attaches a computation to channel ch, which will compute expression x over each of its members, and returns the original channel.
This is an attachment function.
Parameter:
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ch |
A channel. |
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x |
An expression, which is a field name generally or a legal expression consisting of field names; use ~ to reference the current record. |
Return value:
Channel
Example:
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A |
B |
C |
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1 |
=demo.cursor("select EID,NAME,BIRTHDAY,SALARY from EMPLOYEE where EID<10") |
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2 |
=channel() |
=channel() |
=channel() |
Create channels A2, B2 and C2. |
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3 |
=A2.(age(BIRTHDAY)) |
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Attach a computation to channel A2, which will compute age(BIRTHDAY) on BIRTHDAY’s members, and return result to the channel. |
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4 |
=A2.fetch() |
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Execute result set function in channel A2 and keep the current data in channel. |
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5 |
=B2.(SALARY) |
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Attach a computation to channel B2, which will compute SALARY column, and return the original channel B2. |
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6 |
=B2.(~*1.2) |
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Attach a computation to channel B2, which will use ~ to reference the current member of the sequence to compute SALARY*1.2, and return the original channel B2. |
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7 |
=B2.fetch() |
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Execute result set function in channel B2 and keep the current data in channel. |
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8 |
=C2.() |
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Return channel C2. |
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9 |
=C2.fetch() |
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Execute result set function in channel C2 and keep the current data in channel. |
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10 |
=A1.push(A2,B2,C2) |
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Be ready to push data in A1’s cursor into channel A2, B2 and C2, but the action needs to wait. |
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11 |
=A1.fetch() |
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Fetch data from cursor A1 while pushing data into the channel to execute the attached computation and keep the result.
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12 |
=A2.result() |
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Get channel A2’s result:
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13 |
=B2.result() |
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Get channel B2’s result:
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14 |
=C2.result() |
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Get channel C2’s result: |
