I want to insert a variety of SQL queries into a Trino table as a VARCHAR.
There are a multitude of items that throw errors for example single quotes, keywords like "table" being a column name, -- SQL comments that throw errors when Trino is reading the SQL INSERT query.
Is there a data type where I can just dump string type data that may contain things like keywords, SQL comments, single quotes? Trying VARCHAR doesn't seem to be the answer.
Related
I have confirmed that the view returns the correct data when on the SQL Server. But when pulling the raw view through Oracle some of the string columns only contain 1 character for each record, while other columns are fully populated.
Does anyone know what could cause this issue?
The fields that had cutoff characters were NVARCHAR(50). Apparently, Oracle does not pull NVARCHARs correctly from SQL Server. Casting them as VARCHAR(50) in the SQL Server view solved the problem.
I have a predefined SQL data base that we have to work correctly with a reporting software we have purchased. When ever we pull a column of data with the reporting software we get system.indexoutofrangeexception error. On the first table we replaced all Semi Colons ';' with space within the data and this corrected the issue. This column does not have any other special characters within the data only semi colons.
However the data in the second column we need to query contains all different kinds of characters that are probably invalid. The column type is ntext and would like to either change the data directly in the sql database everytime there is a new entry or would changing the format to nvarchar(max) or nvarchar(1024) be suffice?
Thanks for the support I am beyond green at sql.
Your problem is most likely not related to the datatype in your database but the data itself.
Your reporting software seems to have specific requirements that your data does not meet.
I have a very simple SQL statement
SELECT * FROM Table;
but, my query engine returns a syntax error. Why?
Error Details:
An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in >System.Data.dll
Additional information: Incorrect syntax near the keyword 'Table'.
How is this possible? I checked the connection string and it is correct.
I checked my table name and it is also correct.
What I am doing wrong?
Okay, Table is a reserved keyword in all variants of SQL.
If you want to call a table Table, and use it in a statement, you have to tell your sql engine that it is an identifier. To do this you need to use Identifier Qualifiers.
for (MS SQL Server) TSQL use square brackets
SELECT * FROM [Table];
for MySQL use `
SELECT * FROM `Table`;
for Oracle and PostgreSQL use quotation marks,
these are standards compliant.
SELECT * FROM "Table";
for SQLite you can use any of the above, but quotation marks are prefered.
The Identifier Qualifiers tell the engine that this is an identifier (the name of an object.) Not the name of a keyword, even if they happen to be the same. Without your guidance the query engine can get confused and report an error, or worse, do something unexpected.
Using Identifier Qualifiers is good practice, even if the identifers are not keywords.
They better define statements for all parsers, including the fleshy kind.
Naming objects after keywords is generally considered bad practice. So you should try to avoid making identifers the same as keywords. The occasions when a reserved keyword is descriptive of the contents of a table are rare, see the footnote.
e.g. your table is not a Table of tables.
The problem and advice is not limited to Tables, Identifiers are required for all database objects inluding Schema, Views and the many types that exist, standard and vendor-specific.
Another form of good practice is to prefix Table indentifiers with a Schema identifier, this helps the query engine a little.
When including the Schema identifier, the identifer should be qualified,
for (MS SQL Server) TSQL use square brackets
SELECT * FROM [dbo].[Table];
for MySQL use `
SELECT * FROM `dbo`.`Table`;
for Oracle, PostgreSQL and SQLite use quotation marks
SELECT * FROM "dbo"."Table";
even if your Schema is not named after a keyword, as should be the case.
For your reference, to help you avoid conflicts.
A list of TSQL Reserverd Keywords.
A list of MySQl Reserved Keywords.
A list of Oracle Reserved Keywords.
A list of SQLite Reserved Keywords.
A list of PostgreSQL Reserved Keywords.
Notable "gotcha's" include USER and ERROR, which seem to come up when designing systems.
Footnote:
There are occasions when using reseved words for object names may be semantically correct.
Consider the contrived example of an information system for a furniture shop. In this scenario, a table of tables (kitchen, garden, dining, apothecary etc.) may be correct. So, you could argue Table was the correct identifier.
If you always use Identifier Qualifiers, you won't get burned.
If you are using SQL server you need to wrap table in brackets [] as table is keyword in SQL Server
SELECT * FROM [Table]
I've converted a bunch of DML (INSERT/UPDATE/DELETE) queries from Oracle into PostgreSQL and now I need to check whether they produce the same set of rows, i.e. that delete removes the same rows, assuming the oracle and postgresql databases contain the same data initially, update updates the same rows etc. On PostgreSQL side, I can use the returning clause with DML statements, i.e.
INSERT INTO test(id, name) VALUES(42, 'foo') RETURNING *;
What's good about the statement above is that I can prepend 'returning *' to any DML statement without knowing the structure or even the name of the table it's executed against and just get all rows like it's a select statement.
However, it seems to be not that shiny on the Oracle side. According to the documentation, Oracle 8i (the one I'm working with) supports RETURNING clause, but it has to store the result into variables and there seem to be no obvious way to get all result columns instead of manually specifying the column name.
Hence, the question is if there is an oracle statement (or sequence of statements) to emulate PostgreSQL 'returning *' without hard-coding table or column names. In other words, is there a way to write an Oracle function like this:
fn('INSERT INTO test(id, name) VALUES(42, ''foo'')')
It should return the set of rows inserted (or modified in the generic case) by the SQL statement.
Update:
I actually found a very similar question (for the conversion from SQL server, not PostgreSQL, into Oracle). Still, I'd love to hear a more simple answer to that if possible.
I could imagine a solution involving EXECUTE IMMEDIATE, RETURNING, and REF CURSOR, but clearly it will be far from simple. I've previously found solutions such as this one, involving XML to problems where records of arbitrary type are to be used. They're quite freaky, to say the least. I guess you'll have to resort to running two separate queries... Specifically, with Oracle 8i, I'm afraid you won't even be able to profit from most of those features.
In short, I don't think there is any SQL construct as powerful as Postgres ... RETURNING clause in Oracle.
It's not currently possible, especially in an old version of Oracle such as 8i. See this answer to a similar question.
I've been attempting to write embedded SQL statements for DB2 that ultimately gets compiled in C.
I couldn't find a tutorial or manual on the embedded SQL syntax for C for reference. One case I would like to do is to insert data into a table. I know most embedded sql statements need the initalizer EXEC SQL, but that's the extent of my knowledge generally. I'm doing this for an assignment and would appreciate if there are more information regarding this or solution.
Example of a statement to query the database:
EXEC SQL SELECT SNAME, AGE into :sname, :sage
FROM ONE.SAILOR
WHERE sid = :sid;
I like to see what statement allows me to INSERT into the database. I've tried something like the following, but it doesn't work.
EXEC SQL INSERT ....
See IBM's Embedded SQL manual.
Embedded SQL is largely the same no matter what the host language is.
The four dots aren't syntactically valid :-D
The reliable way is the same as with any other INSERT statement: list the columns and the values.
EXEC SQL INSERT INTO SomeTable(Col1, Col2, Col3) VALUES(:hv1, :hv2, :hv3);
Here, the :hv1, :hv2 and :hv3 represent three host variables of types appropriate to the columns in the table. Note that the table could contain other columns than these three as long as those columns have a default specified or accept NULL (which is really just a default default in this case). The unreliable way does not list the columns:
EXEC SQL INSERT INTO SomeTable VALUES(:hv1, :hv2, :hv3);
Now you are dependent on getting the sequence right, and you must provide a value for each column -- there cannot be extra columns in SomeTable.
I just started using sqllite. Besides the good documentation for C++, SQLlist might be a nice thing to have because you can unit-test your code without being dependent on DB2 and it's really easy add with your code.