Hi I have the same question as this post
How do you explicitly delete a SQLite database created with the sqldf library in an R script
However, the user found the answer in a blog and put the link up but the link no longer works. Like the user, I don't understand where tables are stored and can't delete them. I've used the following commands with no success
sqldf("attach 'mydb' as new")
sqldf("create table mytable as SELECT * FROM mytable1", dbname="mydb")
file.remove("mytable")
sqldf("drop table mytable", dbname="mydb")
I get the error "sqldf: table mytable1 already in mydb"
Related
I was trying to dump my PostgreSQL database created via SQLalchemy using python script. Though I have successfully created a database and all the data are getting inserted via web parsing in the ORM I have mapped with. But when I am trying to take a dump for all my insert queries using this
tab = Table(table.__tablename__, MetaData())
x = tab.insert().compile(
dialect=postgresql.dialect(),
compile_kwargs={"literal_binds": True},
)
logging.info(f"{x}")
I am adding values using ORM like this:
for value in vertex_type_values:
data = table(
Type=value["type"],
Name=value["name"],
SizeX=value["size_x"],
SizeY=value["size_y"],
SizeZ=value["size_z"],
)
session.add(data)
session.commit()
here table is the model which i have designed and imported from my local library and vertex_type_values which I have extracted and yield in my script
I am getting the output as
INSERT INTO <tablename> DEFAULT VALUES
So my question is how to get rid of Default Values and get actual values so that I can directly use insert command if my DB crash anytime? I need to know raw SQL for insert command
I have a very simple ADF pipeline to copy data from local mongoDB (self-hosted integration environment) to Azure SQL database.
My pipleline is able to copy the data from mongoDB and insert into SQL db.
Currently if I run the pipeline it inserts duplicate data if run multiple times.
I have made _id column as unique in SQL database and now running pipeline throws and error because of SQL constraint wont letting it insert the record.
How do I check for duplicate _id before inserting into SQL db?
should I use Pre-copy script / stored procedure?
Some guidance / directions would be helpful on where to add extra steps. Thanks
Azure Data Factory Data Flow can help you achieve that:
You can follow these steps:
Add two sources: Cosmos db table(source1) and SQL database table(source2).
Using Join active to get all the data from two tables(left join/full join/right join) on Cosmos table.id= SQL table.id.
AlterRow expression to filter the duplicate _id, it not duplicate then insert it.
Then mapping the no-duplicate column to the Sink SQL database table.
Hope this helps.
You Should implement your SQL Logic to eliminate duplicate at the Pre-Copy Script
Currently I got the solution using a Stored Procedure which look like a lot less work as far this requirement is concerned.
I have followed this article:
https://www.cathrinewilhelmsen.net/2019/12/16/copy-sql-server-data-azure-data-factory/
I created table type and used in stored procedure to check for duplicate.
my sproc is very simple as shown below:
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[spInsertIntoDb]
(#sresults dbo.targetSensingResults READONLY)
AS
BEGIN
MERGE dbo.sensingresults AS target
USING #sresults AS source
ON (target._id = source._id)
WHEN NOT MATCHED THEN
INSERT (_id, sensorNumber, applicationType, place, spaceType, floorCode, zoneCountNumber, presenceStatus, sensingTime, createdAt, updatedAt, _v)
VALUES (source._id, source.sensorNumber, source.applicationType, source.place, source.spaceType, source.floorCode,
source.zoneCountNumber, source.presenceStatus, source.sensingTime, source.createdAt, source.updatedAt, source.updatedAt);
END
I think using stored proc should do for and also will help in future if I need to do more transformation.
Please let me know if using sproc in this case has potential risk in future ?
To remove the duplicates you can use the pre-copy script. OR what you can do is you can store the incremental or new data into a temp table using copy activity and use a store procedure to delete only those Ids from the main table which are in temp table after deletion insert the temp table data into the main table. and then drop the temp table.
I am getting error while inserting data into hive table but data is getting inserted successfully in table.
act = sqlContext.createDataFrame(df,schema)
act.createOrReplaceTempView("act_view")
sqlContext.sql("insert into table project_defect.biweb_t_activity select * from act_view")
Give me this following error:
KeyProviderCache: Could not find uri with key [dfs.encryption.key.provider.uri] to create a keyProvider
I am using Hortonworks Platform, if any one has faced this issues please suggest.
I'm already having a MySQL table in my local machine (Linux) itself, and I have a Hive external table with the same schema as the MySQL table.
I want to sync my hive external table whenever a new record is inserted or updated. Batch update is ok with me to say hourly.
What is the best possible approach to achieve the same without using sqoop?
Thanks,
Sumit
Without scoop, you can create table STORED BY JdbcStorageHandler. Project repository: https://github.com/qubole/Hive-JDBC-Storage-Handler It will work as usual hive table, but query will run on MySQL. Predicate pushdown will work.
DROP TABLE HiveTable;
CREATE EXTERNAL TABLE HiveTable(
id INT,
id_double DOUBLE,
names STRING,
test INT
)
STORED BY 'org.apache.hadoop.hive.jdbc.storagehandler.JdbcStorageHandler'
TBLPROPERTIES (
"mapred.jdbc.driver.class"="com.mysql.jdbc.Driver",
"mapred.jdbc.url"="jdbc:mysql://localhost:3306/rstore",
"mapred.jdbc.username"="root",
"mapred.jdbc.input.table.name"="JDBCTable",
"mapred.jdbc.output.table.name"="JDBCTable",
"mapred.jdbc.password"="",
"mapred.jdbc.hive.lazy.split"= "false"
);
I created a new table in the Bluemix SQL Database service by uploading a csv (baseball.csv) and took the default table name of "baseball".
I created a simple app in Node.js which is just trying to select data from the table with select * from baseball, but I keep getting the following error:
[IBM][CLI Driver][DB2/NT] SQL0204N "USERxxxx.BASEBALL" in an undefined name
Why can't it find my database table?
This issue seems independent of bluemix, rather it is usage error.
This error is possibly caused by following:
The object identified by name is not defined in the database.
User response
Ensure that the object name (including any required qualifiers) is correctly specified in the SQL statement and it exists.
try running "list tables" from command prompt to check if your table spelling is correct or not.
http://www-01.ibm.com/support/knowledgecenter/SSEPGG_9.7.0/com.ibm.db2.luw.messages.sql.doc/doc/msql00204n.html?cp=SSEPGG_9.7.0%2F2-6-27-0-130
I created the table from SQL Database web UI in bluemix and took the default name of baseball. It looks like this creates a case-sensitive table name.
Unfortunately for me, the sql_db libary (and all db2 clients I believe) auto-capitalizes the SQL query into "SELECT * FROM BASEBALL"
The solution was to either
A. Explicitly name my table BASEBALL in the web UI; or
B. Modify my sql query by quoting the table name:
select * from "baseball"
More info at http://www.ibm.com/developerworks/data/library/techarticle/0203adamache/0203adamache.html#N10121