问KDB:如何将字符串数据类型分配给所有列

EN

Tab: ([Key1:string()] Col1:string();Col2:string();Col3:string())

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c     t     f     a
--------------------
Key1            
Col1            
Col2            
Col3            

c.Dict dict = new c.Dict((Object[]) columns.toArray(new String[columns.size()]), data);
c.Flip flip = new c.Flip(dict);

conn.c.ks("upsert", table, flip);

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c     t     f     a
--------------------
Key1  s         
Col1  s         
Col2  s         
Col3  s