T.index( f:h,w;C,…;F,… )

T

An entity table

f

Index file object

w

Filtering condition; retrieve the whose set if the parameter is absent

C

The field for which an index is created

h

Hash index length; can be omitted

F

Field name in an entity table; can be omitted

@2

Work when only parameter f is present; used to load the index file to the memory and can increase performance

@3

 Work when only parameter f is present; used to load the index file to the memory; help achieve higher performance than @2 but occupy more memory space

@0

Close the index to release resources when only parameter f is present

@w

Create a full-text index on column C, which should be a string type single column;

Only support like("*X*") style search; X can be a string made up of letters, numbers or common characters, whose length should be greater than 2, or one or more Chinese characters;

Case-insensitive when the index string is made up of letters;

With this option, parameter h is interpreted as the largest number of records matched with each index string; no such interpretation when h is absent

A

1

=demo.query("select EID,NAME,BIRTHDAY,DEPT,GENDER,HIREDATE,SALARY from employee ")

Return a table sequence.

2

=file("empi.ctx")

3

=A2.create@y(#EID,NAME,BIRTHDAY,DEPT,GENDER,HIREDATE,SALARY)

Create a composite table.

4

=A3.append@i(A1)

Append table sequence A1’s data to the composite table.

5

=file("index_dzdpx")

Create index file object.

6

=A3.index(A5,DEPT=="HR";EID;DEPT)

For data of EID and DEPT fields meeting DEPT=="HR" in composite table A3, create ordered index file index_dzdpx on EID, which is the indexed field.

7

=file("index_px")

Create index file object.

8

=A3.index(A7;EID,NAME)

Create index file index_px for composite table A3 on EID and NAME, which are indexed fields; as parameter F is absent, read all fields of the table.

9

=A3.icursor(EID,NAME,DEPT,SALARY;EID<20;A7,A5)

Query EID, NAME, DEPT and SALARY fields meeting EID<20 in the composite table according to the index file.

A

1

=file("empi.ctx").open()

Open the composite table.

2

=file("index_hs")

Create index file object.

3

=A1.index(A2:10;DEPT,GENDER)

Create a HASH index file whose length is 10 for composite table empi.ctx on DEPT and GENDER, which are the indexed fields.

4

=A1.icursor(NAME,DEPT,GENDER,SALARY;[["HR","M"]].contain(DEPT,GENDER);A2)

Use index file index_hs to query data of NAME, DEPT, GENDER and SALARY fields where DEPT is HR and GENDER is M in the composite table and return a cursor, whose content is as follows:

A

1

=file("empi.ctx").open()

Open the composite table file.

2

=file("index_qw")

Create index file object.

3

=A1.index@w(A2;NAME)

Use @w option to create a full-text index file for composite table empi.ctx on NAME which are the indexed field.

4

=A1.icursor(EID,NAME,BIRTHDAY;like(NAME," *ann *");A2)

Use index file index_qw to query data of EID, NAME and BIRTHDAY fields in the composite table where NAME values contain string “ann” and return result as a cursor, whose content is as follows:

5

=file("index_qw1")

6

=A1.index@w(A5:5;NAME)

Use @w to create a full-text index file, whre the index string is case-insensitive; the value of parameter h is 5 means the largest number of records each index string can match.

7

=A1.icursor(EID,NAME,BIRTHDAY;like(NAME,"*ANN*");A5)

Content of the returned cursor is as follows:

A

1

=file("empi.ctx").open()

Open the composite table file.

2

=A1.index@2(file("index_qw"))

Load the composite table’s index file to the memory.

3

=A1.icursor(EID,NAME,BIRTHDAY;like(NAME,"A*");file("index_qw"))

Use the index file loaded to the memory to query data in the composite table.

4

=A1.index@0(file("index_qw"))

Release the memory resources occupied by the index file.

5

>A1.close()

Close the composite table.