I'm trying to get the rpw 'AID' from the table 'Account'.
SQLCHAR AID;
wsprintf(String, "select [AID] from [Account] where [UserID] = '%s'", User);
Sql.RetCode = Sql.Execute(String);
Sql.RetCode = Sql.Fetch();
Sql.Clear();
sprintf(String, "Here my result: %s", SQL RETURN!);
MsgBox(String);
How can i get the [AID] from the table [Account] ? (For User 'idohadar')
I see that you use some object library to call ODBC function. I do not know this library but I use ODBC from "raw" API or wrap it in my classes.
Raw API is very well described on: http://www.easysoft.com/developer/languages/c/odbc-tutorial-fetching-results.html
You must prepare buffer for values then call SQLFetch() and then read from that buffer.
Related
I have a gcp based environment. I use standard SQL scripting in gcp BigQuery and federated query to cloudsql MySql. Federated query selects data from cloudsql mysql database. I need to select data from cloudsql mysql database based on condition that depends on data in BigQuery. I use variables in standard sql scriping in gcp bigquery to store the value that I select from bigquery. I want to value of this variable in the where clause of mysql query. See following example where I select a date from BigQuery and store it in a variable "BQ_LAST_DATETIME".
DECLARE BQ_LAST_DATETIME DATETIME
SET BQ_LAST_DATETIME = (select max(date_created) from bq_my_dataset.bq_my_table);
Since I am using bigquery federated query to read data out of cloudsql database (https://cloud.google.com/bigquery/docs/cloud-sql-federated-queries) as shown below and I want to use value that I stored in the variable "BQ_LAST_DATETIME" in the mysql query where clause
SELECT * FROM EXTERNAL_QUERY("my-gcp-project.my-region.my-connection2-cloudsql", "select * from mysqlschema.mysql_table where where date_created = #BQ_LAST_DATETIME;" );
Please note that in above query I have used "#BQ_LAST_DATETIME" as a placeholder to show what I want to achieve. I am not sure if I can directly use bigquery scripting variable as query parameter in the "external" query part of federated query.
Any suggestions on how to achieve parametrization of external queries in federated query, or if you know how I could achieve effect similar to what my intent is?
I actually tried following as depicted . I used bigquery scripting variable as query parameter in the "external" query part of federated query. only nuance here is that since the I was dealing with dates I performed a cast and also since the date variable actually is treated as a string I formatted it back to date using mysql STR_TO_DATE as follows
DECLARE BQ_LAST_DATETIME DATETIME
SET BQ_LAST_DATETIME = (select max(date_created) from bq_my_dataset.bq_my_table);
SET BQ_LAST_DATE= CAST(BQ_LAST_DATETIME AS DATE);
SELECT * FROM EXTERNAL_QUERY("my-gcp-project.my-region.my-connection2-cloudsql", "select * from mysqlschema.mysql_table where where date_created = STR_TO_DATE(#BQ_LAST_DATE,'%Y-%m-%d') ;" );
While this query is accepted by parser it is NOT giving expected result.
Basically the value of the variable #BQ_LAST_DATE does not seem to get to MySQL query as expected.
Does anyone know what am I missing ?
Thanks a lot for your help
You can try EXECUTE IMMEDIATE:
DECLARE BQ_LAST_DATETIME STRING;
DECLARE DSQL STRING;
SET BQ_LAST_DATETIME = 'SELECT max(date_created) from bq_my_dataset.bq_my_table';
SET DSQL = '"select * from mysqlschema.mysql_table where date_created = (' || BQ_LAST_DATETIME || ')"';
EXECUTE IMMEDIATE 'SELECT * FROM EXTERNAL_QUERY("my-gcp-project.my-region.my-connection2-cloudsql",' || DSQL || ');'
prep_stmt = con->prepareStatement("SELECT * FROM table WHERE customers in ( ? ) and alive = ?");
prep_stmt->setString(1,customer_string);
prep_stmt->setInt(2,1);
res = prep_stmt->executeQuery();
Here the customer_string is "12,1,34,67,45,14"
When I pass it as a String it always returns a single row, takes the first value only 12.
The sql statement prepared is:
SELECT * FROM table WHERE customers in ( "12,1,34,67,45,14" ) and alive = 1
but I want sql statement to be prepared as:
SELECT * FROM table WHERE customers in (12,1,34,67,45,14 ) and alive = 1
What is the easiest way to achieve the same in C++?
I am assuming you are using the MySQL C++ Connector. Unfortunately it seems that it is not possible to pass array as parameter of prepared statement using this API:
Connector/C++ does not support the following JDBC standard data types: ARRAY, BLOB, CLOB, DISTINCT, FLOAT, OTHER, REF, STRUCT.
https://dev.mysql.com/doc/connector-cpp/en/connector-cpp-usage-notes.html
You can place the value into the query directly by concatenating strings. Be VERY careful to not introduce SQL injection vulnerability. Alternatively use some other API.
I have a table
CREATE TABLE TEST
(
test_column CLOB
)
I want to change the datatype of test_column to LVARCHAR. How can I achieve this? I tried several things until now:
alter table test modify test_column LVARCHAR(2500)
This works, but the content of test_column gets converted from 'test' to '01000000d9c8b7a61400000017000000ae000000fb391956000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000'.
alter table test add tmp_column LVARCHAR(2500);
update test set tmp_column = DBMS_LOB.SUBSTR(test_column,2500,1);
This does not work and I get the following exception:
[Error Code: -674, SQL State: IX000] Method (substr) not found.
Do you have any further ideas?
Using a 12.10.xC5DE instance to do some tests.
From what i could find in the manuals, there isn't a cast from CLOB to other data types.
CLOB data type
No casts exist for CLOB data. Therefore, the database server cannot convert data of the CLOB type to any other data type, except by using these encryption and decryption functions to return a BLOB. Within SQL, you are limited to the equality ( = ) comparison operation for CLOB data. To perform additional operations, you must use one of the application programming interfaces from within your client application.
The encryption/decryption functions mentioned still return CLOB type objects, so they do not do what you want.
Despite the manual saying that there is no cast for CLOB, there is a registered cast in the SYSCASTS table. Using dbaccess , i tried an explicit cast on some test data and got return values similar to the ones you are seeing. The text in the CLOB column is 'teste 01', terminated with a line break.
CREATE TABLE myclob
(
id SERIAL NOT NULL
, doc CLOB
);
INSERT INTO myclob ( id , doc ) VALUES ( 0, FILETOCLOB('file1.txt', 'client'));
SELECT
id
, doc
, doc::LVARCHAR AS conversion
FROM
myclob;
id 1
doc
teste 01
conversion 01000000d9c8b7a6080000000800000007000000a6cdc0550000000001000000000
0000000000000000000000000000000000000000000000000000000000000000000
0000000000
So, there is a cast from CLOB, but it does not seem to be useful for what you want.
So back to the SQL Packages Extension . You need to register this datablade on the database. The files required are located in the $INFORMIXDIR/extend and you want the excompat.* module. Using the admin API, you can register the module by executing the following:
EXECUTE FUNCTION sysbldprepare('excompat.*', 'create');
If the return value is 0 (zero) then the module should now be registered.
SELECT
id
, DBMS_LOB_SUBSTR(doc, DBMS_LOB_GETLENGTH(doc) - 1, 1) as conversion
FROM
myclob;
id 1
conversion teste 01
Another way would be to register your own cast from CLOB to LVARCHAR, but you would have to code an UDR to implement it.
P.S:
Subtracting 1 from the CLOB length to remove the line break.
I need to insert a blob in o oracle database. I am using c++ and ODBC library.
I am stucked at the insert query and update query .It is abstract for me how to make an blob insert query.
I know how to make an query for a non blob column.
My table structure is :
REATE TABLE t_testblob (
filename VARCHAR2(30) DEFAULT NULL NULL,
apkdata BLOB NULL
)
I found an exemple on insert and update :
INSERT INTO table_name VALUES (memberlist,?,memberlist)
UPDATE table_name SET ImageFieldName = ? WHERE ID=yourId
But these structure of querys or abstract to me . What should memberlist be ? why is there "?" where are the values to be inserted ?
Those question marks means that it is PreparedStatement. Such statements are good for both server and client. Server has less work because it is easier to parse such statement, and client do not need to worry about SQLInjection. Client prepares such query, builds buffer for input values and calls it.
Also such statement is executed very quick compared to "normal" queries, especially in loops, importing data from csv file etc.
I don't know what ODBC C++ library you use while ODBC is strictly C library. Other languages like Java or Python can use it too. I think the easiest is example in Python:
cursor = connection.cursor()
for txt in ('a', 'b', 'c'):
cursor.execute('SELECT * FROM test WHERE txt=?', (txt,))
Of course such PreparedStatement can be used in INSERT or UPDATE statements too, and for your example it can look like:
cursor.execute("INSERT INTO t_testblob (filename, apkdata) VALUE (?, ?)", filename, my_binary_data)
I'm having some strange feeling abour sqlite3 parameters that I would like to expose to you.
This is my query and the fail message :
#query
'SELECT id FROM ? WHERE key = ? AND (userid = '0' OR userid = ?) ORDER BY userid DESC LIMIT 1;'
#error message, fails when calling sqlite3_prepare()
error: 'near "?": syntax error'
In my code it looks like:
// Query is a helper class, at creation it does an sqlite3_preprare()
Query q("SELECT id FROM ? WHERE key = ? AND (userid = 0 OR userid = ?) ORDER BY userid DESC LIMIT 1;");
// bind arguments
q.bindString(1, _db_name.c_str() ); // class member, the table name
q.bindString(2, key.c_str()); // function argument (std::string)
q.bindInt (3, currentID); // function argument (int)
q.execute();
I have the feeling that I can't use sqlite parameters for the table name, but I can't find the confirmation in the Sqlite3 C API.
Do you know what's wrong with my query?
Do I have to pre-process my SQL statement to include the table name before preparing the query?
Ooookay, should have looked more thoroughly on SO.
Answers:
- SQLite Parameters - Not allowing tablename as parameter
- Variable table name in sqlite
They are meant for Python, but I guess the same applies for C++.
tl;dr:
You can't pass the table name as a parameter.
If anyone have a link in the SQLite documentation where I have the confirmation of this, I'll gladly accept the answer.
I know this is super old already but since your query is just a string you can always append the table name like this in C++:
std::string queryString = "SELECT id FROM " + std::string(_db_name);
or in objective-C:
[#"SELECT id FROM " stringByAppendingString:_db_name];