Version

    DBExecute

    DBExecute 64x64

    Short description

    Ports

    Metadata

    DBExecute attributes

    Details

    Examples

    Best practices

    See also
    If you’re interested in learning more about this subject, we offer the Databases course in our CloverDX Academy.

    Short description

    DBExecute executes specified SQL/DML/DDL statements against a database connected using the JDBC driver. It can execute queries, transactions, call stored procedures or functions.

    Input parameters can be received through the single input port and output parameters or result set are sent to the first output port. Error information can be sent to the second output port.

    For executing INSERT/DELETE/UPDATE SQL queries operating on single records read from input port of the component, consider using DatabaseWriter instead, as it is optimized for these types of queries.
    Same input metadata Sorted inputs Inputs Outputs Each to all outputs Java CTL Auto-propagated metadata

    -

    ⨯

    0-1

    0-2

    -

    ⨯

    ⨯

    ⨯

    Ports

    Port type Number Required Description Metadata

    Input

    0

    [1]

    Input records for stored procedure or the whole SQL commands.

    any

    Output

    0

    [2]

    Update count and the executed statement.

    Output parameters and result set of stored procedures.

    any

    1

    ⨯

    for error information

    based on input metadata
    1

      Input port must be connected if the Query input parameters attribute is specified or if the whole SQL query is received through the input port.
    2

    The output port must be connected if the Query output parameters or the Return set output fields attribute is specified.

    Metadata

    DBExecute propagates input metadata to the first output port if not calling a stored procedure. It adds two output fields: updateCount and statement.

    DBExecute has no metadata template.

    Metadata on both output ports may contain any number of fields from input (same names and types). Input metadata are mapped automatically according to their name(s) and type(s).

    Since 5.7.0, output metadata may contain two additional fields: updateCount and statement (case insensitive, so UpdateCount or UPDATE_COUNT also works). If present, these fields are populated with the number of updated rows and the executed statement, respectively. This feature only works if the Call as stored procedure attribute is set to false.

    The error output metadata may also contain the statement field and two additional fields for error information, which may have any names and can be set via Autofilling functions: ErrCode and ErrText.

    DBExecute attributes

    Attribute Req Description Possible values

    Basic

    DB connection

    yes

    ID of the DB connection to be used.

    SQL query

    [1]

    An SQL query defined in the graph. Contains SQL/DML/DDL statement(s) that should be executed against database. If a stored procedure or function with parameters should be called or if output data set should be produced, the form of the statement must be the following: {[? = ]call procedureName([?[,?,[…​]])}. (Do not forget to enclose the statement in curly brackets!) At the same time, if the input and/or the output parameters are required, corresponding attributes are to be defined for them (Query input parameters, Query output parameters and/or Result set output fields, respectively).

    If the query consists of multiple statements, they must be separated from each other by specified SQL statement delimiter. Statements will be executed one by one.

    Query URL

    [1]

    One of these two options: Either the name of an external file, including path, defining the SQL query with the same characteristics as described in the SQL query attribute, or the File URL attribute string that is used for port reading. For details, see SQL query received from input port.

    Query source charset

    Encoding of external file specified in theQuery URL attribute.

    E.g. UTF-8 | <other encodings>

    SQL statement delimiter

    A delimiter between individual SQL statements in the SQL query or Query URL attribute. Default delimiter is a semicolon.

    ";" (default) | other character

    Print statements

    By default, SQL commands are not printed. If set to true, they are sent to stdout.

    false (default) | true

    Transaction set

    Specifies whether the statements should be executed in transaction. For more information, see Transaction set. Is applied only if the database supports transactions.

    SET (default) | ONE | ALL | NEVER_COMMIT

    Advanced

    Call as stored procedure

    By default, SQL commands are not executed as stored procedure calls unless this attribute is switched to true. If they are called as stored procedures, JDBC CallableStatement is used. See Calling stored procedures and functions.

    false (default) | true

    Query input parameters

    Used when a stored procedure/function with input parameters is called. It is a sequence of the following type: 1:=$inputField1;…​;n:=$inputFieldN. The value of each specified input field is mapped to the corresponding parameter (whose position in SQL query equals to the specified number). This attribute cannot be specified if SQL commands should be received through the input port.

    Query output parameters

    Used when a stored procedure or function with output parameters or return value is called. It is a sequence of the following type: 1:=$outputField1;…​;n:=$outputFieldN. Value of each output parameter (specified by its position in the SQL query) will be written to the specified field. If the function returns a value, this value is represented by the first parameter. Use "result_set" to denote output parameters that return data sets, typically by returning a cursor, for example "2:=result_set". See Calling stored procedures and functions.

    Result set output fields

    If a stored procedure or function returns a set of data, its output will be mapped to given output fields. The attribute is expressed as a sequence of output field names separated from each other by a semicolon. See Calling stored procedures and functions.

    Deprecated

    Error actions

    The definition of an action that should be performed when the specified query throws an SQL Exception. See Return values of transformations.

    Error log

    The URL of the file to which error messages for specified Error actions should be written. If not set, they are written to Console.
    1

     One of these must be set. If both are specified, Query URL has higher priority.

    Details

    SQL query received from input port

    Transaction set

    Calling stored procedures and functions
    SQL query received from input port

    SQL query can also be received from the input port.

    In this case, two values of the Query URL attribute are allowed:

    • SQL command is sent through the input edge.

      The attribute value is: port:$0.fieldName:discrete.

      Metadata of this edge has neither default delimiter, nor record delimiter, but EOF as delimiter must be set to true.

    • The name of the file containing the SQL command, including the path, is sent through the input edge.

      The attribute value is: port:$0.fieldName:source.

    For more details about reading data from input port, see Input port reading.

    Transaction set

    Options are the following:

    • One statement (no transaction)

      The commit is performed after each query execution. This is needed in case a statement cannot be executed within transaction.

    • One set of statements

      All statements are executed for each input record. The commit is performed after a set of statements.

      For this reason, if an error occurs during the execution of any statement for any of the records, all statements are rolled back for such a record.

    • All statements

      The commit is performed after all statements, only.

      For this reason, if an error occurs, all operations are rolled back.

    • Never commit

      The commit or rollback may be called from other component in a different phase. There is no automatic rollback.

      If no error occurs, the connection closure results in autocommit even if Never commit is selected. If you need to rollback, the rollback must be called before autocommit on session’s termination.

      If you want to use the Never commit option and perform commit or rollback from another component in another phase, set Thread-safe connection in advanced Connection settings to false. Otherwise, each component will have different connection and autocommit will be performed at the end of processing of particular components.
    Calling stored procedures and functions

    The following table summarizes basic configuration examples to call stored procedures, setting input parameters and obtaining output values in the form of output parameters, return values or cursors.

    SQL object Declaration Output SQL query Query input port parameters Query output port parameters Result set output fields

    PROCEDURE remove_customer(id IN NUMBER)

    None

    { call remove_customer(?) };

    1:=$customer_id;

    PROCEDURE find_customer_name_by_id(id IN NUMBER, name OUT VARCHAR)

    Parameter

    { call find_customer_name_by_id(?, ?) };

    1:=$customer_id;

    2:=$customer_name;

    PROCEDURE get_newest_customer(c_cursor OUT SYS_REFCURSOR)

    Cursor

    { call get_newest_customer(?) };

    1:=result_set;

    customer_id;custom_name;customer_address

    PROCEDURE get_customer(id IN NUMBER, c_cursor OUT SYS_REFCURSOR)

    Cursor

    { call get_customer(?, ?) };

    1:=$customer_id;

    2:=result_set;

    customer_id;custom_name;customer_address

    FUNCTION get_customer_name_by_id(id IN NUMBER) RETURN VARCHAR

    Value

    { ? = call get_customer_name_by_id(?) };

    2:=$customer_id;

    1:=$customer_name;

    Examples

    Creating a database table with DBExecute

    Executing multiple queries

    Creating a stored procedure

    Getting errors
    Creating a database table with DBExecute

    This example shows a basic use case of this component.

    Create a database table rivers with two columns: name and length.

    Solution

    Create a database connection RiversConnection. See Creating internal database connections.

    Set the DB Connection to RiversConnection connection.

    Enter the CREATE statement into the SQL Query attribute.

    Attribute Value

    DB Connection

    RiversConnection

    Query URL

    		 
    CREATE TABLE rivers (
    name VARCHAR(50) NOT NULL,
    length INTEGER
);

    If you use one graph to create a database table and insert data to it, do no forget to put DBExecute and the component inserting the data into different phases. DBExecute should be in a lower phase and DatabaseWriter (or other component writing to the database) in a higher phase.

    Executing multiple queries

    DBExecute is not limited to execution of one SQL query.

    Create table rivers as in the previous example. If the table exists, drop it first.

    Solution
    Attribute Value

    DB Connection

    RiversConnection

    Query URL

    		 
    DROP TABLE IF EXISTS rivers;
CREATE TABLE rivers (
    name VARCHAR(50) NOT NULL,
    length INTEGER
);

    Do not forget to end statements with semicolons.

    Note: some databases (e.g. Oracle) do not understand the IF EXISTS part of the query. If you use a database that does not support IF EXISTS, change the first line of the query to DROP TABLE rivers;.

    Creating a stored procedure

    Create a stored procedure that inserts data into the products table. The table has been created with the following query:

    CREATE TABLE products (
    product_name VARCHAR(40) NOT NULL
);
    Solution

    Create a database connection ProductConnection.

    Attribute Value

    DB Connection

    ProductConnection

    Query URL

    		 
    CREATE OR REPLACE FUNCTION add_product(param VARCHAR(40))
RETURNS VOID AS '
BEGIN
    INSERT INTO products (product_name) VALUES(param);
END;
' LANGUAGE plpgsql;

    The example has been tested with PostgreSQL 9.2 and 14.4.

    Getting errors

    This example shows a way to get errors related to an SQL query from the DBExecute component to send it to the next component for further processing.

    The graph uses DBExecute to create a database table bricks. The bricks table contains details on products from our supplier. The table might exist or we could not have permission to create a table and we would like to receive the errors from the database.

    Solution

    Create a database connection ProductConnection.

    Attribute Value

    DB Connection

    ProductConnection

    Query URL

    		 
    CREATE TABLE bricks (
    id INTEGER PRIMARY KEY NOT NULL,
    length integer,
    width integer,
    height integer,
    weight integer
);

    Connect an edge to the second output port of DBExecute.

    Assign metadata to the edge. The metadata should contain a String field that has Autofilling set to ErrCode.

    Best practices

    Upload and download of data

    Do not use the DBExecute component for INSERT and SELECT statements. For uploading data to a database, please use the DatabaseWriter component. Similarly, for downloading use the DatabaseReader component.

    Transferring data within a database

    The best practice to load data from one table to another in the same database is to do it inside the database. You can use the DBExecute component with a query like this:

    insert into my_table select * from another_table

    because pulling data out from the database and putting them in is slower as the data has to be parsed during the reading and formatted when writing.

    Charset

    If the query is specified in an external file (with Query URL), we recommend users to explicitly specify Query source charset.

    Troubleshooting

    Boolean and Oracle JDBC

    Calling arguments or return values of the PL/SQL RECORD, BOOLEAN, or table with non-scalar elements are not supported by Oracle JDBC Drivers. See Oracle JDBC reference

    As a workaround, you can create a wrapper procedure. See Wrapper procedures

    See also

    DatabaseReader

    DatabaseWriter

    Common properties of components

    Specific attribute types

    Others comparison