pg_select
Nome
pg_select -- loop over the result of a query
Sinopse
pg_select conn commandString arrayVar procedure
Descrição
pg_select
submits a query (SELECT statement) to the PostgreSQL server and executes a given chunk of code for each row in the result. The commandString must be a SELECT statement; anything else returns an error. The arrayVar variable is an array name used in the loop. For each row, arrayVar is filled in with the row values, using the column names as the array indices. Then the procedure is executed.
In addition to the column values, the following special entries are made in the array:
- .headers
-
A list of the column names returned by the query.
- .numcols
-
The number of columns returned by the query.
- .tupno
-
The current row number, starting at zero and incrementing for each iteration of the loop body.
Argumentos
- conn
-
The handle of the connection on which to execute the query.
- commandString
-
The SQL query to execute.
- arrayVar
-
An array variable for returned rows.
- procedure
-
The procedure to run for each returned row.
Exemplos
This examples assumes that the table table1
has columns control and name (and perhaps others):
pg_select $pgconn "SELECT * FROM table1;" array {
puts [format "%5d %s" $array(control) $array(name)]
}