Welcome
Migrating and upgrading
You can upgrade to the 15.0.0 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
Migrating Informix® database systems
The HCL Informix® Migration Guide describes how to move data manually between databases, servers, and computers.
Data migration utilities
The dbschema utility
The dbschema utility displays the SQL statements (the schema) that are necessary to replicate database objects.
Syntax of the dbschema command
The dbschema command displays the SQL statements (the schema) that are necessary to replicate a specified database object. The command also shows the distributions that the UPDATE STATISTICS statement creates.
Sequence creation
The dbschema -seq sequence command generates information about sequence creation.

HCL Informix® V15.0.0 documentation
Welcome to the documentation for HCL Informix® 15.0.0 and related client tools and products.
Product overview
HCL Informix® is a fast and scalable database server that manages traditional relational, object-relational, and dimensional databases. Its small footprint and self-managing capabilities are suited to embedded data-management solutions.
Installing
These topics describe how to install HCL Informix® database servers, client products, and modules.
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
Migrating and upgrading
You can upgrade to the 15.0.0 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
- Migrating Informix® database systems
  The HCL Informix® Migration Guide describes how to move data manually between databases, servers, and computers.
  - Overview of migration
  - Migration to and reversion from 15.0.0
  - Migration of data between database servers
  - Data migration utilities
    - External tables
      External tables are a fast and versatile method for moving data between database servers. External tables are the fastest method for loading data into a RAW table with no indexes.
    - The dbexport and dbimport utilities
      The dbexport and dbimport utilities import and export a database and its schema to disk or tape.
    - The dbload utility
      The dbload utility loads data into databases or tables that HCL® Informix® products created. It transfers data from one or more text files into one or more existing tables.
    - The dbschema utility
      The dbschema utility displays the SQL statements (the schema) that are necessary to replicate database objects.
      - Object modes and violation detection in dbschema output
        The output from the dbschema utility shows object modes and supports violation detection.
      - Guidelines for using the dbschema utility
        You can use delimited identifiers with the dbschema utility. The dbschema utility detects database objects that are keywords, mixed case, or that have special characters, and the utility places double quotation marks around those keywords.
      - Syntax of the dbschema command
        The dbschema command displays the SQL statements (the schema) that are necessary to replicate a specified database object. The command also shows the distributions that the UPDATE STATISTICS statement creates.
        Database schema creation
        You can create the schema for an entire database or for a portion of the database.
        dbschema server-specific information
        The dbschema -ss option generates server-specific information. The -ss option always generates the lock mode, extent sizes, and the dbspace name if the dbspace name is different from the database dbspace. In addition, if tables are fragmented, the -ss option displays information about the fragmentation strategy.
        User-defined and complex data types
        The dbschema -u option displays the definitions of any user-defined and complex data types that the database contains. The suboption i adds the type inheritance to the information that the dbschema -u option displays.
        Sequence creation
        The dbschema -seq sequence command generates information about sequence creation.
        Synonym creation
        The dbschema -s command generates information about synonym creation.
        Table, view, or procedure creation
        Several dbschema options generate information that shows the creation of tables, views, and procedures.
        Table information
        The dbschema -ss command retrieves information about fragmented tables, the lock mode, and extent sizes.
        Storage space, chunk, and log creation
        The dbschema -c command generates SQL administration API commands for reproducing storage spaces, chunks, logical logs, and physical logs. If you use the dbschema -c -ns command, the database server generates onspaces or onparams utility commands for reproducing storage spaces, chunks, physical logs, and logical logs.
        Role creation
        The dbschema -r command generates information on the creation of roles.
        Privileges
        The dbschema -p command generates information on privileges.
        Distribution information for tables in dbschema output
        The dbschema -hd command with the name of the table retrieves the distribution information that is stored for a table in a database. If you specify the ALL keyword for the table name, the distributions for all the tables in the database are displayed.
      - Use dbschema output as DB-Access input
        You can use the dbschema utility to get the schema of a database and redirect the dbschema output to a file. Later, you can import the file into and use to re-create the schema in a new database.
    - The LOAD and UNLOAD statements
      You can use the SQL LOAD and UNLOAD statements to move data. The LOAD statement is moderately fast and easy to use, but it only accepts specified data formats. You usually use the LOAD statement with data that is prepared with an UNLOAD statement.
    - The onunload and onload utilities
      The onunload and onload utilities provide the fastest way to move data between computers that use the same database server on the same platform.
    - The onmode utility reversion option
      You use the -b option of the onmode utility to revert to the older database server from which you converted.
    - The onrestorept utility
      You can use the onrestorept utility to restore the database server back to the state that it was in just before the start of the failed upgrade.
Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Embedding Informix®
When you embed HCL Informix®, you can use enterprise-class high-availability and high performance with embeddability features such as easy programmability, a small disk and memory footprint, and silent deployment.
Extending Informix®
Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix includes many built-in extensions that are fully integrated in the database server. Informix also provides modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix.
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
JSON compatibility
You can use the popular JSON-oriented query language created by MongoDB to interact with data stored in HCL Informix®.
Security
You can secure your Informix® database server and the data that is stored in your Informix databases. You can encrypt data, secure connections, control user privileges and access, and audit data security.
SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Troubleshooting HCL Informix®
Several troubleshooting techniques, tools, and resources are available for resolving problems that you encounter in your HCL Informix® database server environment.

Sequence creation

The dbschema -seq sequence command generates information about sequence creation.

The following syntax diagram fragment shows sequence creation.


Element	Purpose	Key Considerations
-seq *sequence*	Displays the CREATE SEQUENCE statement defining *sequence*	None.
-seq all	Displays all CREATE SEQUENCE statements for the database	None.

Running dbschema with option -seq sequitur might produce this output:

CREATE SEQUENCE sequitur INCREMENT 10 START 100 NOCACHE CYCLE

For more information about the CREATE SEQUENCE statement, see the HCL® Informix® Guide to SQL: Syntax.