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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.
Designing and Implementing a Database
The Informix® Database Design and Implementation Guide provides information to help you design, implement, and manage your Informix databases. It includes data models that illustrate different approaches to database design and shows you how to use structured query language (SQL) to implement and manage your databases.
Managing databases
Distributed queries
Transaction processing
When using distributed queries in a transaction processing environment, be aware of the effect of the isolation level of a transaction, the effect of the SET LOCK MODE statement in conjunction with the DEADLOCK_TIMEOUT configuration parameter, and the two-phase commit protocol.
DEADLOCK_TIMEOUT and SET LOCK MODE
When working with distributed queries, you can use the SET LOCK MODE statement in conjunction with the DEADLOCK_TIMEOUT configuration parameter to help prevent server deadlock.

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.
- Designing and Implementing a Database
  The Informix® Database Design and Implementation Guide provides information to help you design, implement, and manage your Informix databases. It includes data models that illustrate different approaches to database design and shows you how to use structured query language (SQL) to implement and manage your databases.
  - Basics of database design and implementation
  - Managing databases
    - Table fragmentation strategies
    - Grant and limit access to your database
    - Distributed queries
      - Overview of distributed queries
      - Configure the database server to use distributed queries
      - Syntax of a distributed query
      - Monitor distributed queries
        Use the onstat -x command to display transaction information originating on the coordinator of a distributed query.
      - Server environment and distributed queries
        Set the DEADLOCK_TIMEOUT configuration parameter and the PDQPRIORITY environment variable to specify information for distributed queries.
      - Logging-type restrictions on distributed queries
      - Transaction processing
        When using distributed queries in a transaction processing environment, be aware of the effect of the isolation level of a transaction, the effect of the SET LOCK MODE statement in conjunction with the DEADLOCK_TIMEOUT configuration parameter, and the two-phase commit protocol.
        Isolation levels
        The isolation level of a transaction is sent to the remote server at the start of the transaction at the remote site. If an isolation level changes during a transaction, the new value is sent to the remote site.
        DEADLOCK_TIMEOUT and SET LOCK MODE
        When working with distributed queries, you can use the SET LOCK MODE statement in conjunction with the DEADLOCK_TIMEOUT configuration parameter to help prevent server deadlock.
        Two-phase commit and recovery
        The two-phase commit protocol is used to ensure that distributed queries are uniformly committed or rolled back across multiple database servers. A database server automatically uses the two-phase commit protocol for any transaction that modifies data on multiple database servers.
  - Object-relational databases

DEADLOCK_TIMEOUT and SET LOCK MODE

When working with distributed queries, you can use the SET LOCK MODE statement in conjunction with the DEADLOCK_TIMEOUT configuration parameter to help prevent server deadlock.

When you request the WAIT option of SET LOCK MODE, the database server protects against the possibility of a deadlock. However, if the database server discovers that a deadlock can occur, it terminates the operation and returns an error.

The DEADLOCK_TIMEOUT configuration parameter specifies the maximum number of seconds that a database server thread can wait to acquire a lock. This value is the default value used by the SET LOCK MODE WAIT statement. This value applies only if you acquire locks on the current and remote database server within the same transaction.