setColumnComment
Syntax
setColumnComment(table, columnComments)
Arguments
table is a DFS table or MVCC table.
columnComments is a dictionary. Its keys are table columns and values are comments for each column.
Details
Add comments to columns of a DFS table or an MVCC table. Use function schema to view column comments.
Examples
$ n=1000000
$ sym=rand(`A`B`C`D`E`F,n)
$ date=rand(2019.06.01..2019.06.10,n)
$ open=rand(100.0,n)
$ high=rand(200.0,n)
$ close=rand(200.0,n)
$ pre_close=rand(200.0,n)
$ change=rand(100.0,n)
$ vol=rand(10000,n)
$ amount=rand(100000.0,n)
$ t=table(sym,date,open,high,close,pre_close,change,vol,amount);
$ db1=database("",VALUE,2019.06.01..2019.06.10)
$ db2=database("",VALUE,`A`B`C`D`E`F)
$ db=database("dfs://db1",COMPO,[db1,db2])
$ pt=db.createPartitionedTable(t,`pt,`date`sym).append!(t);
$ setColumnComment(pt,{sym:"stock ticker", date:"trading date", open:"open price", high:"highest price", low:"lowest price", close:"close price", vol:"trading volume (shares)", amount:"trading volume (dollar)"})
$ schema(pt).colDefs;
name |
typeString |
typeInt |
comment |
---|---|---|---|
sym |
SYMBOL |
17 |
stock ticker |
date |
DATE |
6 |
trading date |
open |
DOUBLE |
16 |
open price |
high |
DOUBLE |
16 |
highest price |
close |
DOUBLE |
16 |
close price |
vol |
INT |
4 |
trading volume (shares) |
amount |
DOUBLE |
16 |
trading volume (dollar) |
$ id=`XOM`GS`AAPL
$ x=102.1 33.4 73.6
$ mt = mvccTable(id, x);
$ setColumnComment(mt, {id:"identifier"})
$ schema(mt).colDefs
name |
typeString |
typeInt |
extra |
comment |
---|---|---|---|---|
id |
STRING |
18 |
identifier |
|
x |
DOUBLE |
16 |