run()

Here’s how to use run() function.

r .run( x i ,… )

Description:

Compute an expression against a record and return the modified record.

Syntax:

r.run(xi,…)

Note:

The function computes the expression x against record r and return the modified record. Usually, it is used to change the field values of r, for example, when x is col1=col2+1, it will change the field value of col1.

Parameter:

r	A record
xi	An expression, which is generally a field name or a legal expression composed of field names, and in which "~" references the current record

Return value:

The modified record

Example:

	A
1	=[[12,23]].new(~(1):col1,~(2):col2)
2	=A1(1).run(col1=col2+1)
3	=A1(1).run(col1=col2+1,col2=col1+col2)

Note:

Difference between r.(x) and r.run(x): r.(x) computes the value of expression x and returns it; r.run(x) modifies r through the computation of x, and returns the modified r.

Related function:

A.run(x₁,x₂,…x_i)

P.run(xi:Fi,…)

P .run( x i : F i ,…)

Description:

Compute expressions against each member of a record sequence.

Syntax:

P.run(xi:Fi,…)

Note:

The function computes expression xi for each record in record sequence/table sequence P, assign the results to Fi field and return P that has been modified. The expression xi uses "~" to reference the current member of P.

Parameter:

P	A record sequence/table sequence
xi	The new value of Fi field
Fi	A field of A

Return value:

The table sequence P that has been modified

Example:

	A
1	=demo.query("select DEPT,NAME,BIRTHDAY from EMPLOYEE")
2	=A1.derive(age(BIRTHDAY):Age)
3	=A2.run(Age+10:Age)

Related function:

r.run()

A.run(x₁,x₂,…x_i)

A .run( x 1 , x 2 ,… x i )

Description:

Compute one or more expressions against each member in a sequence/record sequence and return a sequence composed of values of the expression.

Syntax:

A.run(x)	Compute one expression only.
A.run(x1,x2,…xi)	Compute multiple expressions.

Note:

The function computes expressions xi with each member in sequence/record sequence A and return the modified A. For example, when x is col1=col2+1, it will change the field value of col1.

Parameter:

A	A sequence/ record sequence.
x	An expression, which is generally a field name or a legal expression that is composed of field names, and in which "~" is used to reference the current record.

Option:

  @m  Use parallel algorithm to handle data-intensive or computation-intensive tasks; no definite order for the records in the result set.

Return value:

The modified sequence/record sequence A

Example:

  Use run function to modify the member values.

	A
1	=[1,2,3,4,5]
2	=A1.run(~=~*~)	[1,4,9,16,25], use "~" to reference the current member.

Use run function to switch from EID to Name

	A
1	=demo.query("select * from EMPLOYEE").keys(EID)
2	=demo.query("select * from DEPARTMENT")
3	=A2.run(MANAGER=A1.select@1(EID==A2.MANAGER).NAME)
4	=demo.query("select * from EMPLOYEE")
5	=demo.query("select * from DEPARTMENT")
6	=A5.run@m(MANAGER=A4.select@1(EID==A5.MANAGER).NAME)	Use @m option to increase performance of big data handling.

Use run function to link tables

	A
1	=demo.query("select * from EMPLOYEE")
2	=demo.query("select * from DEPARTMENT")
3	=A2.run(MANAGER=A1.select@1(EID== A2.MANAGER))
4	=A2.MANAGER.STATE	California. When the field value is a record, the dot operator is used to reference a member within the record.

Note:

Difference between A.(x) and A.run(x):

A.(x) evaluates expression x and returns a sequence composed of the values of this expression;

A.run(x) is modifies sequence/record sequence A through the computation of x and returns A which has been modified

Related function:

r.run()

P.run(x_i:F_i,…)

ch .run()

Description:

Compute an expression against each of the records in a channel and return the channel with new field values.

Syntax:

ch.run (x_i:F_i,…)

Note:

The function computes expression x_i against each of the records in channel ch, assigns the results to F_i field and returns the original channel with new field values.  This is an attached computation.

Parameter:

ch	Channel
xi	New values of Fi field
Fi	Field name in the given channel

Return value:

Channel

Example:

	A
1	=demo.cursor("select * from EMPLOYEE")
2	=channel()	Create a channel
3	=A2.run(SALARY+1000:SALARY)	Attach a ch.run() operation to A2’s channel to evaluate the expression SALARY+1000, and return the original channel with the new field values
4	=A2.fetch()	Attach ch.fetch() function that get the final result set to A2’s channel to fetch and store the existing data in the channel
5	=A1.push(A2)	Push data in A1’s cursor into A2’s channel
6	=A1.fetch()
7	=A2.result()

cs .run()

Description:

Compute one or more expressions against each of the records in a cursor.

Syntax:

cs.run (x_i:F_i,…)

Note:

The function computes expression x_i over each record in cursor cs, assigns each result to F_i field, and returns the modified cursor cs. It supports multicursors.

Parameter:

cs	Cursor
xi	An expression
Fi	A field of cs

Return value:

  The modified original cursor

Example:

	A
1	=connect("demo").cursor("select * from EMPLOYEE")
2	=A1.run(SALARY+1000:SALARY)
3	=A2.fetch()
4	=connect("demo").cursor("select DEPT,NAME,BIRTHDAY,1 as AGE from EMPLOYEE")
5	=A4.run(age(BIRTHDAY):AGE)
6	=A5.run(AGE-20:AGE)
7	=A6.fetch()

Related function:

A.run(xi:Fi,…)

T.run ()

Description:

Compute a specified expression on each record of a pseudo table.

Syntax:

T.run (xi:Fi,…)

Note:

The function computes expression xi, assigns the result to Fi, and returns a new pseudo table.

Parameter:

T	A pseudo table
xi	An expression
Fi	A pseudo table field

Return value:

Pseudo table

Example:

	A
1	=create(file).record(["emp.ctx"])	Below is content of composite table emp.ctx:
2	=pseudo(A1)	Generate a pseudo table object
3	=A2.run(SALARY+1000:SALARY)	Compute result of adding 1,000 to pseudo table’s field SALARY and assign the result to the field
4	=A3.import()	Below is content of the result pseudo table: