Is there common approach to translate .hdbtable file to pure SQL create table statement?
You mean translate a HDB Table to pure SQL statement? If this, you can open the table,and click 'Export SQL' button.
As hdbtable uses the same type names as the the CREATE/ALTER TABLE statements you could write an hdbtable->sql-ddl compiler that could run completely without HANA. Just keep in mind that the identifiers in hdbtable definitions will be rendered as quoted identifiers if the hdbtable runtime inside HANA computes the definitions.
Related
I am quite new to GBQ and any help is appreciated it.
I have a query below:
#Standard SQL
create or replace table `xxx.xxx.applications`
as select * from `yyy.yyy.applications`
What I need to do is to add today's date at the end of the table name so it is something like xxx.xxx.applications_<todays date>
basically create a filename with Application but add date at the end of the name applications.
I am writing a procedure to create a table every time it runs but need to add the date for audit purposes every time I create the table (as a backup).
I searched everywhere and can't get the exact answer, is this possible in Query Editor as I need to store this as a Proc.
Thanks in advance
BigQuery doesn't support dynamic SQL at the moment which means that this kind of construction is not possible.
Currently BigQuery supports Parameterized Queries but its not possible to use parameters to dynamically change the source table's name as you can see in the provided link.
BigQuery supports query parameters to help prevent SQL injection when
queries are constructed using user input. This feature is only
available with standard SQL syntax. Query parameters can be used as
substitutes for arbitrary expressions. Parameters cannot be used as
substitutes for identifiers, column names, table names, or other parts
of the query.
If you need to build a query based on some variable's value, I suggest that you use some script in SHELL, Python or any other programming language to create the SQL statement and then execute it using the bq command.
Another approach could be using the BigQuery client library in some of the supported languages instead of the bq command.
3GLs provide mechanisms to prepare statements before executing them. E.g.
SELECT name
FROM people
WHERE age=:AGE
The same query can then be executed for different ages. But can such a statement also be prepared in a "plain" Oracle SQL client? Can the same be done in e.g. SQL Plus or dbForge Studio for Oracle as in Java or C# or any other programming language that supports prepared statements?
In dbForge Studio for Oracle, named parameters can be used, preceded by a colon :
SELECT *
FROM people
WHERE name=:name
The parameters can then be filled in with the "Edit parameters dialog box", available from the SQL toolbar.
I know you didn't ask about PostgreSQL but about Oracle. However, of note, PostgreSQL has this feature right in its SQL language.
The SQL standard includes a PREPARE statement, but it is only for use in embedded SQL. The PostgreSQL version of the PREPARE statement works like this:
PREPARE nameByAge(number) AS
SELECT name
FROM People
WHERE age=$1;
and you use it like this:
EXECUTE nameByAge(18);
EXECUTE nameByAge(50);
So unfortunately for Oracle SQLPlus the answer seems to be no, not bind variables. But SQLPlus has substitution variables, similar to shell scripts. You use them as &1, &2, &3, ... and they get their parameters from the way you call the SQLPlus script.
sqlplus user/password #script.sql 18
sqlplus user/password #script.sql 50
with the script.sql being
SELECT name
FROM People
WHERE age=&1;
this would work, even though it is not bind. But then, do you really care about the slight savings in repeat parse time? In fact Oracle hashes SQL statements and already replaces constants with bind variables to be able to better reuse query plans. So the savings you would get with PREPARE and BIND are really minuscule.
I'm writing a script to create a bunch of tables, and I read in the Microsoft documentation that I should use tick marks (aka grave) to enclose database, table, and field names, but when I run it in SQL Server Management Studio, I get a syntax error on the first tick:
CREATE TABLE `active`.`test` ( … )
^syntax error
So I tried running it thru a lint, and it told me that ` is an invalid character, and it suggested removing them, which totally messed up the script.
What gives?
Use square brackets...
CREATE TABLE [active].[test](...)
The documentation you have linked to is:
The SQL query strings for Windows Installer are restricted to the following formats.
This is not the syntax for SQL Server. I suggest looking at the Transact-SQL Reference instead.
You need to use [] instead of the backtick:
CREATE TABLE [active].[test]
Is there a way to tell NHibernate to use square brackets for all table and column names (like [MyColumn]) when generating the SQL schema export for MS SQL Server? I have a legacy database that uses reserved names for certain columns and running the SQL script generated using NH throws an error because of it.
I want to avoid having to specify this separately for each column.
UPDATE: I'm using the correct dialect:
MsSqlConfiguration.MsSql2008.ConnectionString(connectionString)
UPDATE 2: #UpTheCreek pointed me in the right direction - backticks, which helped me find the answer in the "NHibernate in Action" book (p. 76):
There is no way, apart from quoting all table and column names in backticks, to force NHibernate to use quoted identifiers everywhere.
Easier approach:
SchemaMetadataUpdater.QuoteTableAndColumns(config)
(Before building SessionFactory)
That will quote all the reserved names automatically.
Use backticks in your mapping files around the column names. NH should replace these with the correct character for your db dialect (in your case square brackets).
i.e. use:
<class name="SomeClass" table="`SomeTable`">
NB - It won't work with an apostrophe. The backtick is located top left on most keyboards.
You need to use (or write) the correct dialect for your database
I have a SqlServer db that I would like to port to MySQL. What's the best way to to this. Things that need to be ported are:
Tables (and data)
FileStream → MySQL equivalent?
Stored Procedures
Functions
Data types are relatively similar.
There is no equivalent to FileStream in MySQL - the files must either be stored as BLOBs, or on the file system while the path is stored in the database.
Migrating away from TSQL means:
There's no WITH clause in MySQL - it will have to converted into a derived table/inline view
There's no TOP syntax - these have to be converted to use LIMIT
There's no ranking/analytic functionality in MySQL - can't use ROW_NUMBER, RANK, DENSE_RANK or NTILE. See this article for alternatives.
MySQL views have notoriously limited functionality:
The SELECT statement cannot contain a subquery in the FROM clause.
The SELECT statement cannot refer to system or user variables.
Within a stored program, the definition cannot refer to program parameters or local variables.
The SELECT statement cannot refer to prepared statement parameters.
Any table or view referred to in the definition must exist. However, after a view has been created, it is possible to drop a table or view that the definition refers to. In this case, use of the view results in an error. To check a view definition for problems of this kind, use the CHECK TABLE statement.
The definition cannot refer to a TEMPORARY table, and you cannot create a TEMPORARY view.
Any tables named in the view definition must exist at definition time.
You cannot associate a trigger with a view.
As of MySQL 5.0.52, aliases for column names in the SELECT statement are checked against the maximum column length of 64 characters (not the maximum alias length of 256 characters).
Dynamic SQL will have to be converted to use MySQL's Prepared Statement syntax
A guide/article with some useful tips is available on the official MySQL dev site.
This is not for the faint of heart. Here is an article that explains what you are in for:
http://searchenterpriselinux.techtarget.com/news/column/0,294698,sid39_gci1187176,00.html