I'm currently using the pg-promise library to insert multiple values into a database in the format:
const cs = new pgp.helpers.ColumnSet(['booking_id', {name:'timeslot', cast:'timestamp'}], {table: 'booking'});
// data input values:
const values = [];
bookings.forEach(slot => {
values.push({booking_id: booking_id, timeslot: slot});
});
Where I need timeslot to be a timestamp. However it comes into the API as value like
1515586500.0
Using the above cast property my query gets resolved like so
insert into "booking"("booking_id","timeslot") values(1,'1515586500.0'::timestamp)
however this throws an error of cannot cast type numeric to timestamp without time zone
If I use the to_timestamp function however this works how I need it to e.g
insert into "booking"("booking_id","timeslot") values(1,to_timestamp('1515586500.0'));
Is there any way I can get pg-promise to use to_timestamp rather than the ::timestamp notation?
Change the column definition to this one:
{
name: 'timeslot',
mod: ':raw',
init: c => pgp.as.format('to_timestamp($1)', c.value)
}
or
{
name: 'timeslot',
mod: ':raw',
init: c => pgp.as.format('to_timestamp(${value})', c)
}
...as per the Column type documentation.
Or you can use Custom Type Formatting on the type, to self-format automatically.
Also, you do not need to remap values to suit the ColumnSet object, you use ColumnSet object to fit the data instead. So if the value for column timeslot is in property slot, you just use prop: 'slot' within your column definition to change where the value is coming from.
Related
In my CRUD Rest Service I do an insert into a DB and want to respond to the caller with the created new record. I am looking for a nice way to convert the map to json.
I am running on ballerina 0.991.0 and using a postgreSQL.
The return of the Update ("INSERT ...") is a map.
I tried with convert and stamp but i did not work for me.
import ballerinax/jdbc;
...
jdbc:Client certificateDB = new({
url: "jdbc:postgresql://localhost:5432/certificatedb",
username: "USER",
password: "PASS",
poolOptions: { maximumPoolSize: 5 },
dbOptions: { useSSL: false }
}); ...
var ret = certificateDB->update("INSERT INTO certificates(certificate, typ, scope_) VALUES (?, ?, ?)", certificate, typ, scope_);
// here is the data, it is map<anydata>
ret.generatedKeys
map should know which data type it is, right?
then it should be easy to convert it to json like this:
{"certificate":"{certificate:
"-----BEGIN
CERTIFICATE-----\nMIIFJjCCA...tox36A7HFmlYDQ1ozh+tLI=\n-----END
CERTIFICATE-----", typ: "mqttCertificate", scope_: "QARC", id_:
223}"}
Right now i do a foreach an build the json manually. Quite ugly. Maybe somebody has some tips to do this in a nice way.
It cannot be excluded that it is due to my lack of programming skills :-)
The return value of JDBC update remote function is sql:UpdateResult|error.
The sql:UpdateResult is a record with two fields. (Refer https://ballerina.io/learn/api-docs/ballerina/sql.html#UpdateResult)
UpdatedRowCount of type int- The number of rows which got affected/updated due to the given statement execution
generatedKeys of type map - This contains a map of auto generated column values due to the update operation (only if the corresponding table has auto generated columns). The data is given as key value pairs of column name and column value. So this map contains only the auto generated column values.
But your requirement is to get the entire row which is inserted by the given update function. It can’t be returned with the update operation if self. To get that you have to execute the jdbc select operation with the matching criteria. The select operation will return a table or an error. That table can be converted to a json easily using convert() function.
For example: Lets say the certificates table has a auto generated primary key column name ‘cert_id’. Then you can retrieve that id value using below code.
int generatedID = <int>updateRet.generatedKeys.CERT_ID;
Then use that generated id to query the data.
var ret = certificateDB->select(“SELECT certificate, typ, scope_ FROM certificates where id = ?”, (), generatedID);
json convertedJson = {};
if (ret is table<record {}>) {
var jsonConversionResult = json.convert(ret);
if (jsonConversionResult is json) {
convertedJson = jsonConversionResult;
}
}
Refer the example https://ballerina.io/learn/by-example/jdbc-client-crud-operations.html for more details.?
I'm trying to return a simple, scalar string value from a Postgres DB using Knex. So far, everything I do returns a JSON object with a key (the column name) and the value, so I have to reach into the object to get the value. If I return multiple rows, then I get multiple JSON objects, each one repeating the key.
I could be returning multiple columns, in which case each row would at least need to be an array. I'm not looking for a special case where specifying a single column returns the value without the array -- I'm OK reaching into the array. I want to avoid the JSON object with the repetitive listing of column names as keys.
I've scoured the Knex docs but don't see how to control the output.
My table is a simple mapping table with two string columns:
CREATE TABLE public._suite
(
piv_id character(18) NOT NULL,
sf_id character(18) NOT NULL,
CONSTRAINT _suite_pkey PRIMARY KEY (piv_id)
)
When I build a query using Knex methods like
let myId = 'foo', table = '_suite';
return db(table).where('piv_id', myId).first(['sf_id'])
.then( function(id) { return(id); });
I get {"sf_id":"a4T8A0000009PsfUAE"} ; what I want is just "a4T8A0000009PsfUAE"
If I use a raw query, like
return db.raw(`select sf_id from ${table} where piv_id = '${myId}'`);
I get a much larger JSON object describing the result:
{"command":"SELECT","rowCount":1,"oid":null,"rows":[{"sf_id":"a4T8A0000009Q9HUAU"}],"fields":[{"name":"sf_id","tableID":33799,"columnID":2,"dataTypeID":1042,"dataTypeSize":-1,"dataTypeModifier":22,"format":"text"}],"_parsers":[null],"RowCtor":null,"rowAsArray":false}
What do I have to do to just get the value itself? (Again, I'm OK if it's in an array -- I just don't want the column names.)
Take a look at the pluck method.
db(table).where('piv_id', myId).pluck('sf_id'); // => will return you ["a4T8A0000009PsfUAE"]
I've been trying for a while to insert on MongoDB using only records with no success.
My problem is that I want to create a simple insert function which I send a generic type and it is inserted into the database.
Like so.
let insert (value: 'a) =
let collection = MongoClient().GetDatabase("db").GetCollection<'a> "col"
collection.InsertOne value
From this function, I tried inserting the following records.
// Error that it can't set the Id
type t1 = {
Id: ObjectId
Text: string
}
// Creates the record perfectly but doesn't generate a new Id
type t2 = {
Id: string
Text: string
}
// Creates the record and autogenerates the Id but doesn't insert the Text, and there are two Ids (_id, Id#)
type t3 = {
mutable Id: ObjectId
Text: string
}
// Creates the record and autogenerates the Id but for every property it generates two on MongoDB (_id, Id#, Text, Text#)
type t4 = {
mutable Id: ObjectId
mutable Text: string
}
So does anyone can think of a solution for this or am I stuck having to use a class.
// Works!!!
type t5() =
member val Id = ObjectId.Empty with get, set
member val Name = "" with get, set
Also, does anyone has any Idea of why when the C# MongoDB library translates the mutable he gets the property with the # at the end?
I would be fine with having all my properties set as mutable, although this wouldn't be my first choice, having he create multiple properties on the DB is quite bad.
You could try annotating your records with CLIMutable (and no mutable fields).
The #s end up in the DB because MongoDB using reflection and F# implementing mutable with backing fields fieldName#
Let's say I have a Postgres database (9.3) and there is a table called Resources. In the Resources table I have the fields id which is an int and data which is a JSON type.
Let's say I have the following records in said table.
1, {'firstname':'Dave', 'lastname':'Gallant'}
2, {'firstname':'John', 'lastname':'Doe'}
What I want to do is write a query that would return all the records in which the data column has a json element with the lastname equal to "Doe"
I tried to write something like this:
records = db_session.query(Resource).filter(Resources.data->>'lastname' == "Doe").all()
Pycharm however is giving me a compile error on the "->>"
Does anyone know how I would write the filter clause to do what I need?
Try using astext
records = db_session.query(Resource).filter(
Resources.data["lastname"].astext == "Doe"
).all()
Please note that the column MUST have a type of a JSONB. The regular JSON column will not work.
Also you could explicitly cast string to JSON (see Postgres JSON type doc).
from sqlalchemy.dialects.postgres import JSON
from sqlalchemy.sql.expression import cast
db_session.query(Resource).filter(
Resources.data["lastname"] == cast("Doe", JSON)
).all()
If you are using JSON type (not JSONB) the following worked for me:
Note the '"object"'
query = db.session.query(ProductSchema).filter(
cast(ProductSchema.ProductJSON["type"], db.String) != '"object"'
)
I have some GeoJSON in a JSON (not JSONB) type column and none of the existing solutions worked, but as it turns out, in version 1.3.11 some new data casters were added, so now you can:
records = db_session.query(Resource).filter(Resources.data["lastname"].as_string() == "Doe").all()
Reference: https://docs.sqlalchemy.org/en/14/core/type_basics.html#sqlalchemy.types.JSON
Casting JSON Elements to Other Types
Index operations, i.e. those invoked by calling upon the expression
using the Python bracket operator as in some_column['some key'],
return an expression object whose type defaults to JSON by default, so
that further JSON-oriented instructions may be called upon the result
type. However, it is likely more common that an index operation is
expected to return a specific scalar element, such as a string or
integer. In order to provide access to these elements in a
backend-agnostic way, a series of data casters are provided:
Comparator.as_string() - return the element as a string
Comparator.as_boolean() - return the element as a boolean
Comparator.as_float() - return the element as a float
Comparator.as_integer() - return the element as an integer
These data casters are implemented by supporting dialects in order to
assure that comparisons to the above types will work as expected, such
as:
# integer comparison
data_table.c.data["some_integer_key"].as_integer() == 5
# boolean comparison
data_table.c.data["some_boolean"].as_boolean() == True
According sqlalchemy.types.JSON, you can do it like this
from sqlalchemy import JSON
from sqlalchemy import cast
records = db_session.query(Resource).filter(Resources.data["lastname"] == cast("Doe", JSON)).all()
According to this, pre version 1.3.11, the most robust way should be like this, as it works for multiple database types, e.g. SQLite, MySQL, Postgres:
from sqlalchemy import cast, JSON, type_coerce, String
db_session.query(Resource).filter(
cast(Resources.data["lastname"], String) == type_coerce("Doe", JSON)
).all()
From version 1.3.11 onward, type-specific casters is the new and neater way to handle this:
db_session.query(Resource).filter(
Resources.data["lastname"].as_string() == "Doe"
).all()
I have a model:
case class MyModel(
id: Pk[Long] = NotAssigned,
startsAt: Option[DateTime] = None,
addedAt: Option[DateTime] = None
)
object MyModel {
// .....................
SQL("""
INSERT INTO my_table(starts_at)
VALUES ({startsAt})
"""
).on('startsAt -> newItem.startsAt).executeInsert()
}
Both startst_at and added_at have a default value of now() in Postgresql and don't allow null values in them. It doesn't cause any error for addedAt (because I never pass it to the server from the client) but it does cause the error for startsAt if it's not specified at newItem.startsAt and, thus, is equal to None and, thus, it's being passed as null.
org.postgresql.util.PSQLException: ERROR: null value in column "starts_at" violates not-null constraint
What I want is be able to specify startsAt whenever I want it and pass it to the server, meaning if I specify it then that value should be passed to the server, if not - nothing should be passed and the server should use its default value now(). I don't want to specify the default value at the client because it's already set at the server at the db level.
How about this SQL fix:
insert into my_table(starts_at)
values (COALESCE({startsAt}, now())
Updated: requirement is to use the default value of the column
The only way that I know of to get the server to use the default value of a column in an insert, is not to mention that column in the columns list. For example (not tested):
startsAt.map { date =>
SQL("""insert into my_table(starts_at) values({startsAt})""")
.on('startsAt -> date)
.execute()
}.orElse {
SQL("""insert into my_table() values()""")
.execute()
}