exportavro()
Description:
Export data to an Avro data file.
Syntax:
exportavro(avrofile,A/cs,Fi:Ti,...)
Note:
External library function (See External Library Guide).
The function exports data in a table sequence or a cursor to an Avro data file and returns a file object.
When parameter Ti is absent, esProc automatically identifies the data type according to Fi values of table sequence A or cursor cs. As Avro data files do not have time data type such as date, time and datetime, a field of such a data type needs to be specified as long type and values will be exported in milliseconds. For example, the exported value for 2023-11-29 00:45:24 is 1701189924000.
Parameter:
|
avrofile |
Avro file object that cannot be omitted; do not support remote file objects such as httpfile() and Qfile() |
|
A/cs |
A table sequence/ cursor |
|
Fi |
Field name; export all fields by default |
|
Ti |
Specify data type of the to-be-exported field(s), which can be string, boolean, bytes, double, float, int and long |
Option:
|
@a |
Append-export; overwrite the existing data by default |
Return vlaue:
File object
Example:
|
|
A |
|
|
1 |
=file("user1.avro") |
Read the Avro file. |
|
2 |
=connect("mysql") |
|
|
3 |
=A2.query("select * from orders") |
Return a table sequence. |
|
4 |
=exportavro(A1,A3) |
Export all data of table sequence A3 to overwrite the existing data in user1.avro. |
|
5 |
=importavro(A4) |
The exported values of a time type field is in miliseconds. |
|
6 |
=A5.run(datetime(odate):odate) |
|
|
7 |
=exportavro@a(A1,A3,oid:int,oname:string,odate:long) |
Append specified data in table sequence A3 to user1.avro. |
|
8 |
=exportavro@a(A1,A3,oid,oname,odate) |
Same as above. |
