DBSCHEMA FLAGS AS VIRUS CODE

The final outer commit() in the calling code commits the transaction. The call to commit() again does nothing, but pops one level of nesting. However, the Transaction keeps track of the 'depth' of the nesting of ensureTransaction() scopes. We recognize that a database transaction is pending, so do not start a new one. If there is already a transaction pending, the following happens. If the transaction has not been committed, the code assumes an error has occurred and aborts the transaction. If the transaction has been committed then the code continues on. When the try-with-resources block completes it closes the transaction. If the code executes successfully, the call to tx.commit() then completes the transaction. This ensures that everyone in this scope/thread participates in the same transaction. Subsequent calls to getConnection() on this thread return the same connection. When there is no transaction already pending on this scope object, a Connection object is created that is associated with the current thread. Site = Table.insert(user, AccountsSchema.getTableInfoSites(), site) Try (DbScope.Transaction tx = scope.ensureTransaction()) Here is the recommended pattern to follow:ĭbSchema schema = DbSchema.get( 'core', DbSchemaType.Module) This is very easy to handle using DbScope.ensureTransaction(). This is especially true when you may be writing a helper function that does not know whether a higher level routine has already started a transaction or not. Writing correct transaction code directly using JDBC can be tricky. However, DbScope.getConnection() is available if you need it.ĭbSchema schema = DbSchema.get('core', DbSchemaType.Module) ĭbScope also provides a very helpful abstraction over JDBC’s built-in transaction api. You usually do not need to directly handle jdbc Connections, as most of our helpers take a DbScope/DbSchema/TableInfo directly rather than a Connection. We also think of a DbScope as a collection of schemas, the caching layer for meta data associated with schemas and tables, and our transaction manager.

DBSCHEMA FLAGS AS VIRUS UPDATE

For instance, if the url provides the value of a primary key of a row to update or delete, your code must validate that the container of that row matches the container of the current request.ĭbScope directly corresponds to a configured in your Tomcat webapp.xml (usually labkey.xml or ROOT.xml), and is therefore a source of jdbc connections that you can use directly in your code.

If you are relying on these default security checks, it is very important to make sure that your code only operates on rows associated with the current container. We know the current user has insert permission in the current containerĪssert getContainer().hasPermission(getUser(),InsertPermission.class) For instance, the security annotations on an action are evaluated against the SecurityPolicy associated with the 'container' of the current class InsertAction extends AbstractIssueAction All requests (API or UI) to the LabKey server are done in the context of a container, and that container has a SecurityPolicy that is used as the default for evaluating permissions. Many tables in LabKey are partitioned into containers (aka folders in the UI) by a column named 'container' that joins to ntainers. However, be mindful of common patterns involving the 'container' column. The rules that any particular API or code path may need to enforce can be completely custom, so there is no blanket rule about what you must do. It is very important to remember that when you are directly manipulating the database, you are responsible for enforcing permissions.

When using a TableInfo it’s important to keep in mind which world you are dealing with (DbSchema or UserSchema). The TableInfo class is a very important class and is shared between both DbSchema and UserSchema. The 'user-level' objects start with DefaultSchema which hands out UserSchema objects. This topic does not cover the the 'user schema' layer that presents an abstraction of the underlying database to the user and which supports our APIs and LabKey SQL engine.Īs a guideline, the 'low-level' objects start with DbScope and DbSchema and spread out from there. 'Low-level' specifically means access to JDBC functionality to communicate directly with the database and the various helpers we use internally that wrap JDBC.

This topic covers low-level database access from Java code running in LabKey Server.

Dbschema flags as virus