This question already has answers here:
Copying data from one SQLite database to another
(9 answers)
SQLite: Easiest way to copy a table from one database to another?
(2 answers)
Closed last month.
I'm trying to copy table data from one database to another using this command:
INSERT INTO database2.table2 SELECT * from database1.table1
But I run into an error.
I have two databases called database1.db and database2.db
Here's my code:
database1_path = "/home/user/Desktop/database1.db";
database2_path = "/home/user/Documents/database2.db";
{
QSqlDatabase db1 = QSqlDatabase::addDatabase("QSQLITE");
db1.setDatabaseName(database1_path);
QSqlDatabase db2 = QSqlDatabase::addDatabase("QSQLITE");
db2.setDatabaseName(database2_path);
if(!db1.open() && !db2.open())
{
qDebug() << "databases are NOT open!";
}
else
{
QString insert = QString("INSERT INTO '/home/user/Desktop/database1.db'.table1 SELECT * FROM '/home/user/Documents/database2.db'.table2;");
QSqlQuery query(insert, db1);
if(!query.exec(insert))
{
qDebug() << "Error:" << query.lastError().text();
}
}
}
And here is the error I get:
Error: "no such table: /home/user/Desktop/database1.db.table1 Unable to execute statement"
I also tried:
"INSERT INTO database1.table1 SELECT * FROM database2.table2;"
and:
"INSERT INTO db1.table1 SELECT * FROM db2.table2;"
But the same error occurred...
How can I solve this problem?
You cannot open two databases with two different connection and references the other one from another connection. For your use case you need to use the attach command in sql, so that your connection can references both databases.
ATTACH DATABASE '/home/user/Documents/database2.db' AS second_database;
INSERT INTO table1 SELECT * FROM second_database.table2;
Of course that assume that both database/table have compatible schema.
Related
I work with large databases that needs to be stored into a server.
So, to work with them on Rstudio I have to open a connection to my Microsoft SQL Server with the dbConnect function :
conn <- dbConnect(odbc(),"myconnection",uid="***",pwd="***",schema="dbo",access="readonly")
and in order to use dplyr, I have to create data references with the tbl function :
data <- tbl(conn, "data")
But one of the online dataframe contains a columns that I can't read because I dont have the access, but I can read everything else.
The SQL query behind the tbl() function is :
SELECT * FROM data
and this is my problem.
Even when I try to select a specific column it doesn't work (see below), so I can't create my references and I can't work.
select(tbl(conn, "data"), "columnX")
=
SELECT columnX FROM data
I think this is the tbl() function and the call of "SELECT *" that blocks me.
Do you know what can I do ? Is there smilar functions that could resolve my problem ?
If you know the columns that you have access to, then one option is to bypass the default access SELECT * FROM ... with your own SQL query.
A remote table is defined by two components:
The database conneciton
The query to the database
When you connect with the default approach tbl(conn, 'data') then it defaults to a query SELECT * FROM data.
But here is another approach:
custom_query = 'SELECT columnX FROM data'
remote_table = tbl(conn, dbplyr::sql(customer_query))
This question already has an answer here:
How to read multiple result sets returned from a SQL Server stored procedure in R
(1 answer)
Closed 3 years ago.
I am using RODBC to query data from SQL SERVER.
How can I get both tables when the result contains two tables?
Currently my code is as follow
library(RODBC)
channel <- odbcDriverConnect("driver={SQL Server};server=xxxx;atabase=xx;uid=xx;pwd=xxx")
initdata<- sqlQuery(channel,paste("select * from roles;select * from seat"))
odbcClose(channel)
The initdata contains result only from table roles
In fact, my query is a stored procedure like "exec XXX" and the stored procedure returns multiple tables. I wonder if there is a way to get all the result tables.
why don't you use 2 results or dataframes?
dataframes:
initroles <- sqlFetch(channel, "roles")
initseats <- sqlFetch(channel, "seat")
resultsets:
initroles <- sqlQuery(channel, "select * from roles")
initseats <- sqlQuery(channel, "select * from seat")
My syntax might be a little off, but I would try
SELECT * FROM roles JOIN seat ON roles.id = seat.id
Where roles.id and seat.id are the ID variables that link roles and seat.
Sorry for posting this even though there're a few posts about this , but they're not helping.
I'm using sqlite with QT , I wanted to do a simple query but it gives me this error:
file is encrypted or is not a database Unable to execute statement
Some posts' comments say that the DB may be corrupt, I used another program and created a test table from scratch and still has the same problem, this is the code:
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("AdmissionTestDB.sql");
db.open();
if(db.isOpen())
{
QSqlQuery q = db.exec("SELECT * FROM USERS");
if(!q.lastError().isValid())
{
qDebug()<<"works!";
while(q.next())
{
qDebug()<<q.value(8).toString();
}
}
else
qDebug()<<"---db failed to open! , error: "<<q.lastError().text();
db.close();
return true;
}
qDebug()<<"db failed to open! , error: "<<db.lastError().text();
return false;
More Information hopefully it would help solving this:
1- I'm using SQLITE 3
2- The problem happens when I use QSqlQuery q = db.exec("SELECT * FROM USERS"); so the DB actually opens!
3- I used two GUI programs to create the DB one of them is the latest version of SQLiteStudio which is version 3.0.4
I have a SQLite database in one system, I need to extract the data stored in SQLite to Oracle database. How do I do this?
Oracle provides product called the Oracle Database Mobile Server (previously called Oracle Database Lite) which allows you to synchronize between a SQLite and an Oracle database. It provides scalable bi-directional sync, schema mapping, security, etc. The Mobile Server supports both synchronous and asynchronous data sync. If this is more than a one-time export and you need to keep your SQLite and Oracle Databases in sync, this is a great tool!
Disclaimer: I'm one of the Product Managers for Oracle Database Mobile Server, so I'm a bit biased. However, the Mobile Server really is a great tool to use for keeping your SQLite (or Berkeley DB) and Oracle Databases in sync.
You'll have to convert the SQLite to a text file (not certain of the format) and then use Oracle to load the database from text (source is http://www.orafaq.com/wiki/SQLite). You can use the .dump command from the SQLite interactive shell to dump to a text file (see the docs for syntax).
SQL Loader is a utility that will read a delimited text file and import it into an oracle database. You will need to map out how each column from your flat file out of sqlite matches to the corresponding one in the Oracle database. Here is a good FAQ that should help you get started.
If you are a developer, you could develop an application to perform the sync. You would do
SELECT name FROM sqlite_master WHERE type='table'
to get the table names, then you could re-create them in Oracle (you can do DROP TABLE tablename in Oracle first, to avoid a conflict, assuming SQLite will be authoritative) with CREATE TABLE commands. Getting the columns for each one takes
SELECT sql FROM sqlite_master WHERE type='table' and name='MyTable'
And then you have to parse the result:
string columnNames = sql.replace(/^[^\(]+\(([^\)]+)\)/g, '$1').replace(/ [^,]+/g, '').split(',');
string[] columnArray = columnNames.Split(',');
foreach (string s in columnArray)
{
// Add column to table using:
// ALTER TABLE MyTable ADD COLUMN s NVARCHAR(250)
}
A StringBuilder can be used to collect the table name with its columns to create your INSERT command. To add the values, it would just be a matter of doing SELECT * FROM MyTable for each of the tables during your loop through the table names you got back from the initial query. You would iterate the columns of the rows of the datatable you were returned and add the values to the StringBuilder:
INSERT INTO MyTable ( + columnA, columnB, etc. + ) VALUES ( datarow[0], datarow[1], etc. + ).
Not exactly like that, though - you fill in the data by appending the column name and its data as you run through the loops. You can get the column names by appending s in that foreach loop, above. Each column value is then set using a foreach loop that gives you each object obj in drData.ItemArray. If all you have are string fields, it's easy, you just add obj.ToString() to your StringBuilder for each column value in your query like I have below. Then you run the query after collecting all of the column values for each row. You use a new StringBuilder for each row - it needs to get reset to INSERT INTO MyTable ( + columnA, columnB, etc. + ) VALUES ( prior to each new row, so the new column values can be appended.
If you have mixed datatypes (i.e. DATE, BLOB, etc.), you'll need to determine the column types along the way, store it in a list or array, then use a counter to determine the index of that list/array slot and get the type, so you know how to translate your object into something Oracle can use - whether that means simply adding to_date() to the result, with formatting, for a date (since SQLite stores these as date strings with the format yyyy-MM-dd HH:mm:ss), or adding it to an OracleParameter for a BLOB and sending that along to a RunOracleCommand function. (I did not go into this, below.)
Putting all of this together yields this:
string[] columnArray = null;
DataTable dtTableNames = GetSQLiteTable("SELECT name FROM sqlite_master WHERE type='table'");
if (dtTableNames != null && dtTableNames.Rows != null)
{
if (dtTableNames.Rows.Count > 0)
{
// We have tables
foreach (DataRow dr in dtTableNames.Rows)
{
// Do everything about this table here
StringBuilder sb = new StringBuilder();
sb.Append("INSERT INTO " + tableName + " ("); // we will collect column names here
string tableName = dr["NAME"] != null ? dr["NAME"].ToString() : String.Empty;
if (!String.IsNullOrEmpty(tableName))
{
RunOracleCommand("DROP TABLE " + tableName);
RunOracleCommand("CREATE TABLE " + tableName);
}
DataTable dtColumnNames = GetSQLiteTable("SELECT sql FROM sqlite_master WHERE type='table' AND name='"+tableName+"'");
if (dtColumnNames != null && dtColumnNames.Rows != null)
{
if (dtColumnNames.Rows.Count > 0)
{
// We have columns
foreach (DataRow drCol in dtTableNames.Rows)
{
string sql = drCol["SQL"] != null ? drCol["SQL"].ToString() : String.Empty;
if (!String.IsNullOrEmpty(sql))
{
string columnNames = sql.replace(/^[^\(]+\(([^\)]+)\)/g, '$1').replace(/ [^,]+/g, '').split(',');
columnArray = columnNames.Split(',');
foreach (string s in columnArray)
{
// Add column to table using:
RunOracleCommand("ALTER TABLE " + tableName + " ADD COLUMN " + s + " NVARCHAR(250)"); // can hard-code like this or use logic to determine the datatype/column width
sb.Append("'" + s + "',");
}
sb.TrimEnd(",");
sb.Append(") VALUES (");
}
}
}
}
// Get SQLite Table data for insertion to Oracle
DataTable dtTableData = GetSQLiteTable("SELECT * FROM " + tableName);
if (dtTableData != null && dtTableData.Rows != null)
{
if (dtTableData.Rows.Count > 0)
{
// We have data
foreach (DataRow drData in dtTableData.Rows)
{
StringBuilder sbRow = sb; // resets to baseline for each row
foreach (object obj in drData.ItemArray)
{
// This is simplistic and assumes you have string data for an NVARCHAR field
sbRow.Append("'" + obj.ToString() + "',");
}
sbRow.TrimEnd(",");
sbRow.Append(")");
RunOracleCommand(sbRow.ToString());
}
}
}
}
}
}
All of this assumes you have a RunOracleCommand() void function that can take a SQL command and run it against an Oracle DB, and a GetSQLiteTable() function that can return a DataTable from your SQLite DB by passing it a SQL command.
Note that this code is untested, as I wrote it directly in this post, but it is based heavily on code I wrote to sync Oracle into SQLite, which has been tested and works.
I have 2 SQLite databases with common data but with different purposes and I wanted to avoid reinserting data, so I was wondering if it was possible to copy a whole table from one database to another?
You'll have to attach Database X with Database Y using the ATTACH command, then run the appropriate Insert Into commands for the tables you want to transfer.
INSERT INTO X.TABLE SELECT * FROM Y.TABLE;
// "INSERT or IGNORE" if you want to ignore duplicates with same unique constraint
Or, if the columns are not matched up in order:
INSERT INTO X.TABLE(fieldname1, fieldname2) SELECT fieldname1, fieldname2 FROM Y.TABLE;
Easiest and correct way on a single line:
sqlite3 old.db ".dump mytable" | sqlite3 new.db
The primary key and the columns types will be kept.
Consider a example where I have two databases namely allmsa.db and atlanta.db. Say the database allmsa.db has tables for all msas in US and database atlanta.db is empty.
Our target is to copy the table atlanta from allmsa.db to atlanta.db.
Steps
sqlite3 atlanta.db(to go into atlanta database)
Attach allmsa.db. This can be done using the command ATTACH '/mnt/fastaccessDS/core/csv/allmsa.db' AS AM;
note that we give the entire path of the database to be attached.
check the database list using sqlite> .databases
you can see the output as
seq name file
--- --------------- ----------------------------------------------------------
0 main /mnt/fastaccessDS/core/csv/atlanta.db
2 AM /mnt/fastaccessDS/core/csv/allmsa.db
now you come to your actual target. Use the command
INSERT INTO atlanta SELECT * FROM AM.atlanta;
This should serve your purpose.
For one time action, you can use .dump and .read.
Dump the table my_table from old_db.sqlite
c:\sqlite>sqlite3.exe old_db.sqlite
sqlite> .output mytable_dump.sql
sqlite> .dump my_table
sqlite> .quit
Read the dump into the new_db.sqlite assuming the table there does not exist
c:\sqlite>sqlite3.exe new_db.sqlite
sqlite> .read mytable_dump.sql
Now you have cloned your table.
To do this for whole database, simply leave out the table name in the .dump command.
Bonus: The databases can have different encodings.
Objective-C code for copy Table from a Database to another Database
-(void) createCopyDatabase{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
NSString *maindbPath = [documentsDir stringByAppendingPathComponent:#"User.sqlite"];;
NSString *newdbPath = [documentsDir stringByAppendingPathComponent:#"User_copy.sqlite"];
NSFileManager *fileManager = [NSFileManager defaultManager];
char *error;
if ([fileManager fileExistsAtPath:newdbPath]) {
[fileManager removeItemAtPath:newdbPath error:nil];
}
sqlite3 *database;
//open database
if (sqlite3_open([newdbPath UTF8String], &database)!=SQLITE_OK) {
NSLog(#"Error to open database");
}
NSString *attachQuery = [NSString stringWithFormat:#"ATTACH DATABASE \"%#\" AS aDB",maindbPath];
sqlite3_exec(database, [attachQuery UTF8String], NULL, NULL, &error);
if (error) {
NSLog(#"Error to Attach = %s",error);
}
//Query for copy Table
NSString *sqlString = #"CREATE TABLE Info AS SELECT * FROM aDB.Info";
sqlite3_exec(database, [sqlString UTF8String], NULL, NULL, &error);
if (error) {
NSLog(#"Error to copy database = %s",error);
}
//Query for copy Table with Where Clause
sqlString = #"CREATE TABLE comments AS SELECT * FROM aDB.comments Where user_name = 'XYZ'";
sqlite3_exec(database, [sqlString UTF8String], NULL, NULL, &error);
if (error) {
NSLog(#"Error to copy database = %s",error);
}
}
The Easiest way to do is through SQLite Studio
If you don't have download from https://download.cnet.com/SQLiteStudio/3000-10254_4-75836135.html
Steps:
1.Add both the databases.
2.Click View tab and then databases as shown in the picture.
3.Right click the table you want to copy and copy it.
Paste the table after right clicking the database where you want to paste.
Now you're done
First scenario: DB1.sqlite and DB2.sqlite have the same table(t1), but DB1 is more "up to date" than DB2. If it's small, drop the table from DB2 and recreate it with the data:
> DROP TABLE IF EXISTS db2.t1; CREATE TABLE db2.t1 AS SELECT * FROM db1.t1;
Second scenario: If it's a large table, you may be better off with an INSERT if not exists type solution. If you have a Unique Key column it's more straight forward, otherwise you'd need to use a combination of fields (maybe every field) and at some point it's still faster to just drop and re-create the table; it's always more straight forward (less thinking required).
THE SETUP: open SQLite without a DB which creates a temporary in memory main database, then attach DB1.sqlite and DB2.sqlite
> sqlite3
sqlite> ATTACH "DB1.sqlite" AS db1
sqlite> ATTACH "DB2.sqlite" AS db2
and use .databases to see the attached databases and their files.
sqlite> .databases
main:
db1: /db/DB1.sqlite
db2: /db/DB2.sqlite
I needed to move data from a sql server compact database to sqlite, so using sql server 2008 you can right click on the table and select 'Script Table To' and then 'Data to Inserts'. Copy the insert statements remove the 'GO' statements and it executed successfully when applied to the sqlite database using the 'DB Browser for Sqlite' app.
If you use DB Browser for SQLite, you can copy the table from one db to another in following steps:
Open two instances of the app and load the source db and target db side by side.
If the target db does not have the table, "Copy Create Statement" from the source db and then paste the sql statement in "Execute SQL" tab and run the sql to create the table.
In the source db, export the table as a CSV file.
In the target db, import the CSV file to the table with the same table name. The app will ask you do you want to import the data to the existing table, click yes. Done.