Importing SQL Code
This chapter describes how to import SQL code from a text file into InterSystems SQL. When you import SQL code, InterSystems IRIS® data platform prepares and executes each line of SQL using Dynamic SQL. If it encounters a line of code it cannot parse, SQL import skips over that line of code and continues to prepare and execute subsequent lines until it reaches the end of the file. All SQL code import operations import to the current namespace.
SQL Import is primarily used to import Data Definition Language (DDL) commands, such as CREATE TABLE, and to populate tables using INSERT, UPDATE, and DELETE commands. SQL import does prepare and execute SELECT queries, but does not create a result set.
SQL import can be used to import InterSystems SQL code. It can also be used for code migration, to import SQL code from other vendors (FDBMS, Informix, InterBase, MSSQLServer, MySQL, Oracle, Sybase). Code from other vendors is converted to InterSystems SQL code and executed. SQL import cannot import all SQL commands into InterSystems SQL. It imports those commands and clauses that are compatible with the InterSystems IRIS implementation of the SQL standard. Incompatible features are commonly parsed, but ignored.
SQL import can successfully prepare an SQL query — creating a corresponding cached query, where appropriate — but it does not execute the query.
You perform SQL code import by invoking the appropriate method from the %SYSTEM.SQL.Schema class. When importing SQL code, these methods can create two other files: an Errors.log file which records errors in parsing SQL commands, and an Unsupported.log file, which contains the literal text of lines that the method does not recognize as an SQL command.
This chapter describes importing different types of SQL code:
Importing non-InterSystems SQL: FDBMS, Informix, InterBase, MSSQLServer, MySQL, Oracle, Sybase
Importing InterSystems SQL
You can import InterSystems SQL code from a text file using either of the following %SYSTEM.SQL.Schema methods:
ImportDDL() is a general-purpose SQL import method. This method runs as a background (non-interactive) process. To import InterSystems SQL you specify “IRIS” as the third parameter.
Run() is an InterSystems SQL import method. This method runs interactively from the Terminal. It prompts you to specify the location of the import text file, the location to create the Errors.log file and the Unsupported.log file, and other information.
The following example imports the InterSystems IRIS SQL code file pathname mysqlcode.txt, executing the SQL commands listed in that file in the current namespace:
By default, ImportDDL() creates an errors log file, as specified in the second parameter. This example, which omits the second parameter, creates by default a file named mysqlcode_Errors.log in the same directory as the SQL code file. This log file is created even when there is nothing written to it.
When executing ImportDDL() from the Terminal, it first lists the input file, then the error log file, then lists each SQL command imported, as shown in the following example:
Importing SQL Statements from file: c:\InterSystems\mysqlcode.txt Recording any errors to principal device and log file: c:\InterSystems\mysqlcode_Errors.log SQL statement to process (number 1): CREATE TABLE Sample.NewTab (Name VARCHAR(40)) Preparing SQL statement... Executing SQL statement... DONE SQL statement to process (number 2): CREATE INDEX NameIDX ON Sample.NewTab (Name) Preparing SQL statement... Executing SQL statement... DONE Elapsed time: 7.342532 seconds
If an error occurs in any SQL command, the Terminal display the error, as shown in the following example:
SQL statement to process (number 3): INSERT INTO Sample.MyStudents (StudentName,StudentDOB) SELECT Name, DOB FROM Sample.Person WHERE Age <= '21' Preparing SQL statement... ERROR #5540: SQLCODE: -30 Message: Table 'SAMPLE.PERSON' not found Pausing 5 seconds - read error message! (Type Q to Quit)
If you do not Quit within 5 seconds, ImportDDL() proceeds to execute the next SQL command. The error is recorded in the errors log file with a timestamp, the user name, and the namespace name.
Import File Format
An SQL text file must be an unformatted file such as a .txt file. Each SQL command must begin on its own line. An SQL command may be broken into multiple lines and indentation is permitted. Each SQL command must be followed by a GO statement on its own line.
The following is an example of a valid InterSystems SQL import file text:
CREATE TABLE Sample.MyStudents (StudentName VARCHAR(32),StudentDOB DATE) GO CREATE INDEX NameIdx ON TABLE Sample.MyStudents (StudentName) GO INSERT INTO Sample.MyStudents (StudentName,StudentDOB) SELECT Name, DOB FROM Sample.Person WHERE Age <= '21' GO INSERT INTO Sample.MyStudents (StudentName,StudentDOB) VALUES ('Jones,Mary',60123) GO UPDATE Sample.MyStudents SET StudentName='Smith-Jones,Mary' WHERE StudentName='Jones,Mary' GO DELETE FROM Sample.MyStudents WHERE StudentName %STARTSWITH 'A' GO
Supported SQL Commands
Not all valid InterSystems SQL commands can be imported. The following is a list of supported InterSystems SQL commands:
CREATE TABLE, ALTER TABLE, DROP TABLE
CREATE VIEW, ALTER VIEW, DROP VIEW
CREATE INDEX all index types, except bitslice
CREATE USER, DROP USER
INSERT, UPDATE, INSERT OR UPDATE, DELETE
SELECT for optimizer plan mode only
Code Migration: Importing non-InterSystems SQL
You can import SQL code that is in the SQL format used by other vendors. Code from other vendors is converted to InterSystems SQL code and executed. The following methods are provided:
To import SQL in a specific format you specify the name of that format as the first parameter: FDBMS, Informix, InterBase, MSSQLServer (or MSSQL), MySQL, Oracle, or Sybase.
The following example imports the MSSQL code file mssqlcode.txt, executing the SQL commands listed in that file in the current namespace:
Note that if the third parameter is MSSQL, Sybase, Informix, or MySQL, the first parameter can be either an SQL code file pathname or a two-element %List with the first element the SQL code file pathname and the second element is the I/O translation table to use.
Individual interactive methods are provided in %SYSTEM.SQL.Schema to import the following types of SQL: LoadFDBMS(), LoadInformix(), LoadInterBase(), LoadMSSQLServer(), LoadOracle(), and LoadSybase(). These methods runs interactively from the Terminal. It prompts you to specify the location of the import text file, the location to create the Errors.log file and the Unsupported.log file, and other information.
ImportDDLDir() allow you to import SQL code from multiple files in a directory. This method runs as a background (non-interactive) process. It supports Informix, MSSQLServer, and Sybase. All files to be imported must have a .sql extension suffix.
ImportDir() allow you to import SQL code from multiple files in a directory. Provides more options than ImportDDLDir(). This method runs as a background (non-interactive) process. It supports MSSQLServer, and Sybase. You can specify a list of allowed file extension suffixes.