channel()
Here’s how to use channel() function.
channel()
Description:
Create a channel.
Syntax:
|
channel() |
Create a channel |
Note:
The function creates a channel.
Return value:
A channel
Example:
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A |
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1 |
=demo.cursor("select * from SCORES where CLASS = 'Class one'") |
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2 |
=channel() |
Create a channel |
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3 |
>A2.select(STUDENTID==1) |
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4 |
>A2.fetch() |
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5 |
=A1.push(A2) |
Push data in A1’s cursor to A2’s channel |
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6 |
=A1.fetch() |
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7 |
=A2.result() |
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channel( cs )
Description:
Create a channel and push data in a specified cursor into it.
Syntax:
|
channel(cs) |
Note:
The function creates a channel, pushes data in cursor cs into it, and returns a channel. This is equivalent to cs.push(channel()).
Parameter:
|
cs |
A cursor |
Return value:
A channel
Example:
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A |
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1 |
=demo.cursor("select * from SCORES where CLASS = 'Class one'") |
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2 |
=channel(A1) |
Create a channel and be ready to push data in A1’s cursor into the new channel, which is equivalent to =A1.push(channel()), and return a channel |
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3 |
>A2.select(STUDENTID==1) |
Attach a computation to A2’s channel |
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4 |
>A2.fetch() |
Keep data in A2’s channel |
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5 |
=A1.fetch() |
Push data into A2’s channel when data is fetched from the cursor |
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6 |
=A2.result() |
Get data from A2’s channel
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channel( cs )
Description:
Create a cluster channel and push data in a specified cluster cursor into it.
Syntax:
|
channel(cs) |
Note:
The function creates a cluster channel as synchronously segmented as cluster cursor cs, and pushes data in cs into it.
Parameter:
|
cs |
A cluster cursor |
Return value:
A cluster channel
Example:
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A |
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1 |
=file("emp1.ctx","192.168.0.119:8281") |
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2 |
=A1.open() |
Open a cluster table |
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3 |
=A2.attach(table1) |
Retrieve cluster entity table table1 |
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4 |
=A3.memory() |
Create a cluster in-memory table |
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5 |
=A4.cursor() |
Return a cluster cursor |
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6 |
=channel(A5) |
Be ready to push data in A5’s cursor into A6’s channel and return a cluster channel |
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7 |
=A6.fetch() |
Keep data of the cluster channel |
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8 |
=A5.fetch() |
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9 |
=A6.result() |
Get data from the cluster channel |
channel( ch )
Description:
Create a channel and push data in another channel into it.
Syntax:
|
channel(ch) |
Note:
The function creates a channel, pushes data in channel ch into it, and returns a channel. This is equivalent to ch.push(channel()).
Parameter:
|
ch |
A channel |
Return value:
A channel
Example:
|
|
A |
|
|
1 |
=demo.cursor("select * from SCORES where CLASS = 'Class one'") |
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|
2 |
=channel() |
Create a channel |
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3 |
=channel(A2) |
Create a channel and be ready to push data in A2’s channel into the new channel, which is equivalent to =A2.push(channel()) |
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4 |
>A2.select(STUDENTID==1) |
Attach a computation to A2’s channel to select records where STUDENTID is 1 |
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5 |
>A3.select(STUDENTID==2) |
Attach a computation to A3’s channel to select records where STUDENTID is 2 |
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6 |
=A2.fetch() |
Keep the current data in A2’s channel |
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7 |
=A3.fetch() |
Keep the current data in A3’s channel |
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8 |
=A1.push(A2) |
Ready to push A1’s cursor into Channel A2 |
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9 |
=A1.fetch() |
Perform the push action defined in A8 when data is fetched from the cursor |
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10 |
=A2.result() |
Get data from channel A2
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11 |
=A3.result() |
Get data from channel A3
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channel( ch )
Description:
Create a cluster channel and push data in another cluster channel into it.
Syntax:
|
channel(ch) |
Note:
The function creates a cluster channel as synchronously segmented as cluster channel ch, and pushes data in ch into it.
Parameter:
|
ch |
A cluster channel |
Return value:
A cluster channel
Example:
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|
A |
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|
1 |
=file("emp1.ctx":[1],"192.168.0.119:8281") |
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2 |
=A1.open() |
Open a cluster table |
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3 |
=A2.attach(table1) |
Retrieve cluster entity table table1 |
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4 |
=A3.cursor() |
Return a cluster cursor |
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5 |
=channel(A4) |
Create a channel, be ready to push data in A4’s cluster cursor into the new channel, and return a cluster channel |
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6 |
=channel(A5) |
Create a channel, be ready to push data in A5’s cluster channel into the new channel, and return a cluster channel |
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7 |
=A5.fetch() |
Keep data of the cluster channel |
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8 |
=A6.fetch() |
Keep data of the cluster channel |
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9 |
=A4.fetch() |
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10 |
=A5.result() |
Get data from the cluster channel |
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11 |
=A6.result() |
Get data from the cluster channel |