I have created a function within r which generates a variable called value.
This value now needs to be inserted into the database for which I am using RMySQL package
but When I try to run the function I get the following error
Error in .local(conn, statement, ...) :
unused arguments ("Aryan", ");")
The function is very long and works well until the point where the variable generated is inserted into the database which is as under:
pedd<- function(breed, thattrait) {
library(DBI)
library(RMySQL)
...
...
if (thattrait == "weight"){
rs<- fn$dbSendQuery(con,
"INSERT INTO mytable
(weight, race)
VALUES ('$value', ", race, ");")
} else {
inser <- paste0("Update mytable Set ",wean," = '$value' where race = ", race, "")
rswean<- fn$dbSendQuery(con, inser)
}
I am calling the function thus :
pedd("Aryan", "weight")
I cannot understand where I am wrong.
Related
I have following JSON data I would like to decode to Lua to access each the publish_topic and sample_rate value.
{"00-06-77-2f-37-94":{"publish_topic":"/stations/test","sample_rate":5000}}
If I understand correctly the Lua table will look like this:
{00-06-77-2f-37-94 = "publish_topic":"/stations/test","sample_rate":5000}
Next I would go through the table to save each value into a local variable.
However, if I try printing out the values of the table (using following code), I get 'nil' as return. Is the code for reading table values wrong?
Does the table have two values or is it just the one: ["publish_topic":"/stations/test","sample_rate":5000] ?
lua_value = JSON:decode(data)
for _,d in pairs(lua_value) do
print(lua_value[d])
end
local topic = lua_value[0]
local timer = lua_value[1]
end
Edit: I am using following JSON library for Lua: http://regex.info/blog/lua/json
Edit2: #Piglet: I implemented your script and modified it by adding a table (conversionTable) in which both elements "publish_topic":"/stations/test" and "sample_rate:5000" would be respectively saved in the variables pubtop and rate. When I however print each of both variables, nil ist returned in both cases.
How can I extract the information out of this table to save in variables?
Ultimately I actually only would like to save the values "/stations/test" and "5000" into these variables. Would I need to parse each of the elements above to get these or is there another way?
local pubtop
local rate
local function printTable(t)
local conversionTable = {}
for k,v in pairs(t) do
if type(v) == "table" then
conversionTable [k] = string.format("%q: {", k)
printTable(v)
print("}")
else
print(string.format("%q:", k) .. v .. ",")
end
end
pubtop = conversionTable[0]
rate = conversionTable[1]
end
local lua_value
local function handleOnReceive(topic, data, _, _)
print("handleOnReceive: topic '" .. topic .. "' message '" .. data .. "'")
-- This sample publishes the received messages to test/topic2
print(data)
lua_value = JSON:decode(data)
printTable(lua_value)
print(pubtop)
print(rate)
end
client:register('OnReceive', handleOnReceive)
I don't know which json library you're using so I can't tell you wether JSON:decode(data) is the correct way.
Assuming lua_value would like like so:
local lua_value = {
["00-06-77-2f-37-94"] = {
publish_topic = "/stations/test",
sample_rate = 5000
}
}
Then your loop
for _,d in pairs(lua_value) do
print(lua_value[d])
end
will indeed print nil.
lua_value has a single element at key "00-06-77-2f-37-94" which is a table.
Each loop iteration will give you a key value pair. So d is actually the value and hence the inner table of lua_value
So you're actually doing this:
local innerTable = lua_value["00-06-77-2f-37-94"]
print(lua_value[innerTable])
Of course lua_value[innerTable] is nil.
Edit:
Try something like
function printTable(t)
for k,v in pairs(t) do
if type(v) == "table" then
print(string.format("%q: {", k))
printTable(v)
print("}")
else
print(string.format("%q:", k) .. v .. ",")
end
end
end
printTable(lua_value)
I am trying to run a SQL query using Oracle's json_value() function using a PreparedStatement.
Assume the following table setup:
drop table foo cascade constraints purge;
create table foo
(
id integer primary key,
payload clob,
constraint ensure_json check (payload IS JSON STRICT)
);
insert into foo values (1, '{"data": {"k1": 1, "k2": "foo"}}');
The following SQL query works fine:
select *
from foo
where json_value(payload, '$.data.k1') = '1'
and returns the expected row.
However, when I try to run this query using a PreparedStatement like in the the following piece of code:
String sql =
"select *\n" +
"from foo\n" +
"where json_value(payload, ?) = ?";
PreparedStatement pstmt = conection.prepareStatement(sql);
pstmt.setString(1, "$.data.k1");
pstmt.setString(2, "1");
ResultSet rs = pstmt.executeQuery();
(I removed all error checking from the example to keep it simple)
This results in:
java.sql.SQLException: ORA-40454: path expression not a literal
The culprit is passing the json path value (parameter index 1), the second parameter is no problem.
When I replace (only) the first parameter with a String constant json_value(payload, '$.data.k1') = ? the prepared statement works fine.
In a desperate attempt, I also tried including the single quotes in the parameter: pstmt.setString(1, "'$.data.k1'") but not surprisingly, Oracle wouldn't accept it either (same error message).
I also tried using json_value(payload, concat('$.', ?) ) and only passing "data.k1" as the parameter - same result.
So, the question is:
How can I pass a JSON path expression to Oracle's json_value function using a PreparedStatement parameter?
Any ideas? Is this a bug in the driver or in Oracle? (I couldn't find anything on My Oracle Support)
Or is this simply a case of "not implemented"?
Environment:
I am using Oracle 18.0
I tried the 18.3 and 19.3 version of the ojdbc10.jar driver together with OpenJDK 11.
It isn't the driver - you get the same thing with dynamic SQL:
declare
result foo%rowtype;
begin
execute immediate 'select *
from foo
where json_value(payload, :1) = :2'
into result using '$.data.k1', '1';
dbms_output.put_line(result.payload);
end;
/
ORA-40454: path expression not a literal
ORA-06512: at line 4
And it isn't really a bug, it's documented (emphasis added):
JSON_basic_path_expression
Use this clause to specify a SQL/JSON path expression. The function uses the path expression to evaluate expr and find a scalar JSON value that matches, or satisfies, the path expression. The path expression must be a text literal. See Oracle Database JSON Developer's Guide for the full semantics of JSON_basic_path_expression.
So you would have to embed the path literal, rather than bind it, unfortunately:
declare
result foo%rowtype;
begin
execute immediate 'select *
from foo
where json_value(payload, ''' || '$.data.k1' || ''') = :1'
into result using '1';
dbms_output.put_line(result.payload);
end;
/
1 rows affected
dbms_output:
{"data": {"k1": 1, "k2": "foo"}}
or for your JDBC example (keeping the path as a separate string as you presumably want that to be a variable really):
String sql =
"select *\n" +
"from foo\n" +
"where json_value(payload, '" + "$.data.k1" + "') = ?";
PreparedStatement pstmt = conection.prepareStatement(sql);
pstmt.setString(1, "1");
ResultSet rs = pstmt.executeQuery();
Which obviously isn't what you want to do*, but there doesn't seem to be an alternative. Other than turning your query into a function and passing the path variable in to that, but then the function would have to use dynamic SQL, so the effect is much the same - maybe easier to handle SQL injection concerns that way though.
* and I'm aware you know how to do this the embedded way, and know you want to use bind variables because that's the correct thing to do; I've spelled it out more than you need for other visitors *8-)
My go app shall support multiple databases. Meaning, running the same binary with different databases, the database the app is working with will be determined by configuration.
The problem is, each database has it's own prepared statements syntax.
Example:
db.Prepare("select p, f, t from mytable where p = $1")
Will work for postgres but will not work for mysql.
db.Prepare("select p, f, t from mytable where p = ?")
Will work for mysql but will not work for postgres.
Off curse I can solve it by editing the string on runtime or maintaining multiple queries.
Is there a better way?
I do not want to have some huge abstraction with an external library that will take control on all my db access, but if there is some light weight library that just magically fix the syntax, I am good with that.
EDIT:
Summarising what I have said before, the part that bothers me is that for mysql you will have to use "?" while for postgres you will have to use $1, $2...
Cheers
I found db.Rebind() to help with this. So:
name := "my name"
var p = property{}
// language=SQL
s := "SELECT * FROM property WHERE name=?"
err := db.Get(&p, db.Rebind(s), name)
The language comment at the top is so that IntelliJ can still syntax-check the SQL statement for me in the UI.
I also had to write separate CREATE statements for each database (my application is simultaneously supporting mysql, postgres, and sqlite).
I also found the UPDATE statement syntax between mysql and sqlite to be the same, but postgres required special handling. Since my UPDATE statements are very consistent, I was able to write a function to just kludge-translate from the mysql dialect to the postgres dialect. This is definitely not a generic solution but worked well enough for my unit and integration tests to pass. YMMV.
// RebindMore takes a MySQL SQL string and convert it to Postgres if necessary.
// The db.Rebind() handles converting '?' to '$1', but does not handle SQL statement
// syntactic changes needed by Postgres.
//
// convert: "UPDATE table_name SET a = ?, b = ?, c = ? WHERE d = ?"
// to: "UPDATE table_name SET (a, b, c) = ROW (?, ?, ?) WHERE d = ?"
func RebindMore(db *sqlx.DB, s string) string {
if db.DriverName() != "postgres" {
return s
}
if !strings.HasPrefix(strings.ToLower(s), "update") {
return db.Rebind(s)
}
// Convert a MySQL update statement into a Postgres update statement.
var idx int
idx = strings.Index(strings.ToLower(s), "set")
if idx < 0 {
log.Fatal().Msg("no SET clause in RebindMore (" + s + ")")
}
prefix := s[:idx+3]
s2 := s[idx+3:]
idx = strings.Index(strings.ToLower(s2), "where")
if idx < 0 {
log.Fatal().Msg("no WHERE clause in RebindMore (" + s + ")")
}
suffix := s2[idx:]
s3 := s2[:idx]
s4 := strings.TrimSpace(s3)
arr := strings.Split(s4, ",")
var names = ""
var values = ""
for i := 0; i < len(arr); i++ {
nameEqValue := arr[i]
s5 := strings.ReplaceAll(nameEqValue, " ", "")
nvArr := strings.Split(s5, "=")
if names != "" {
names += ","
}
names += nvArr[0]
if values != "" {
values += ","
}
values += nvArr[1]
}
s6 := prefix + " (" + names + ") = ROW (" + values + ") " + suffix
return db.Rebind(s6)
}
Call it this way:
// language=SQL
s := RebindMore(db, "UPDATE table_name SET a = ?, b = ? WHERE c = ?")
db.MustExec(s, value1, value2)
At some point I will need to add migration, and expect to just add separate code per DB to handle the differences (like for CREATE).
One final thing worth pointing out is that MySQL and Postgres handle capitalization very differently. I ended up just converting every table and column name to lower_case to avoid unnecessary complexity.
In this particular case use a place holder {{ph}} in the end of the SQL and use strings.Replace() to replace it with ? Or $1 according to the db driver.
I'am working with r and mysql database and I don't know how catch an insert data into table error in mysql.
I have this:
status <- tryCatch({ AnalyzerDb.insert_data_frame(dataset) })
But when I run the code I have an error:
Error en mysqlExecStatement(conn, statement, ...) :
RS-DBI driver: (could not run statement: Duplicate entry '00001002-2014-01-17 00:00:00' for key 'PRIMARY')
But when I view the value in status var, the variable has NULL value.
Thanks
tryCatch works by you defining functions that handle errors and warnings. If you don't supply tryCatch with any such handles, nothing will be done.
The documentation has several examples illustrating this, as well as a long description outlining how it works.
Something like this:
tryCatch(log("a"),error = function(e) cat("I found an error"))
I have defined this function:
myDivideTryCatchInformation <- function(StatusVector, status ) {
if (class(status) == "try-warning") {
StatusVector[4] = StatusVector[4] + 1
} else if (class(status) =="try-error") {
StatusVector[5] = StatusVector[5] + 1
} else {
StatusVector[3] = StatusVector[3] + 1
}
return(StatusVector)
}
params: StatusVector: this is a vector with 6 positions: XXX, rows, ok, warnings, errors, XXX
and status is the result of try function.
I am trying to delete multiple rows in the sqlite table in my Adobe AIR app (runtime 2.5).
Here is the statement, using the "IN" operator:
"DELETE FROM mylist WHERE tdId IN (tdId1, tdId2, tdId3, ...)";
Where tdId1, tdId2, etc. will be determined at runtime based on which row(s) the user chooses to delete. The user can delete arbitrary number of rows.
I've tried something like:
//delete statement text
"DELETE FROM mylist WHERE tdId IN :tdId";
//delete statement parameters: take 1.
//Got "argument error: near ':tdId': syntax error"
deleteStmt.parameters[":tdId"] = "(26, 32)";
//delete statement parameters: take 2.
//Also got "argument error: near ':tdId': syntax error"
var arr:Array = [26, 32];
deleteStmt.parameters[":tdId"] = arr;
How I go about deleting multiple rows?
[Edit] So it looks like the aforementioned cached statement with parameter [":tdId"] doesn't work when deleting multiple rows. When attempting to execute the delete statement multiple times in asynchronous mode, after the very first row in the queue is deleted, Flash throws the following error:
"Error #3110: Operation cannot be
performed while SQLStatement.executing
is true."
It would seem too much of trouble to chain these deletes with a callback. So I guess I am using my last resort: building the sql at runtime. Conclusion: Cached statements can't be used in these kind of situations...
The problem occurs when you insert the parameter "(26,32)". As the parameter is not purely a substitution of value, it represents a variable to SQL, NOT A STRING. Hence you statement effectively became (or roughly) in your first take...
"DELETE FROM mylist WHERE tdId IN '(26,32)'"
Hence your error, due to the syntax... In your second take it gets worse...
"DELETE FROM mylist WHERE tdId IN *Array(26,32)*"
As the variable does not convert to a string value, this does not actually happen. But what happens is that when the interprater (SQL) tries to understand the code after the 'IN' text, it gets an ARRAY object, which it has completely no idea on what to do... Its not even a valid SQL type....
Solution? [I yet to fully test it, so please do]
var toDel:Array = [26,32]
//delete statement text
var baseStr:String = "DELETE FROM mylist WHERE tdId IN (";
var midStr:String = '';
//delete statement parameters: Processing parameter
for( var i = 0; i < toDel.length; i++ ) {
deleteStmt.parameters[i] = toDel[i];
if(midStr.length > 0) { midStr += ' , '; }
midStr += '?';
}
deleteStmt.text = baseStr + midStr + ' )';
//Then execute
So what happens in this case is that u effectively execute...
"DELETE FROM mylist WHERE tdId IN ( :val1 , :val2 )"
In this way you still maintain the safe (good practice) use of parameters, without converting everything to a string.
EDIT: if you dun understand the use of parameter / '?' refer to :
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/data/SQLStatement.html#parameters
If the IN clause does not allow parameters, you can try old-school SQL style: append multiple
" OR (tdId = :param" + paramCounter.toString() + ")"
to the SQL string