v2.1

About MogDB
- MogDB Introduction
- Comparison Between MogDB and openGauss
- MogDB Release Notes
  - MogDB 2.1.1
  - MogDB 2.1.0
- Open Source Components
- Usage Limitations
- Terms of Use
Quick Start
- MogDB Playground
- Container-based MogDB Installation
- Installation on a Single Node
- MogDB Access
  - Use CLI to Access MogDB
    - gsql
    - pgcli
  - Use GUI to Access MogDB
    - Data Studio
    - DBeaver
  - Use Middleware to Access MogDB
    - Use WebLogic to Configure MogDB Data Sources
    - Use WebSphere to Configure MogDB Data Sources
  - Use Programming Language to Access MogDB
    - Java
    - C/C++
    - Python
    - Go
    - Rust
    - NodeJS
- Using Sample Dataset Mogila
Characteristic Description
Installation Guide
- Container Installation
- Simplified Installation Process
- Standard Installation
  - Installation Overview
  - Preparing for Installation
    - Environment Requirement
    - Modifying OS Configuration
  - Installing MogDB
  - Verifying the Installation
  - Recommended Parameter Settings
  - Uninstalling MogDB
- Manual Installation
Administrator Guide
AI Features Guide
- Overview
- Predictor: AI Query Time Forecasting
- X-Tuner: Parameter Optimization and Diagnosis
- SQLdiag: Slow SQL Discovery
- A-Detection: Status Monitoring
- Index-advisor: Index Recommendation
- DeepSQL
- AI-Native Database (DB4AI)
Security Guide
- Database Security Management
Developer Guide
- Application Development Guide
  - Development Specifications
  - Development Based on JDBC
  - Development Based on ODBC
  - Development Based on libpq
    - Development Based on libpq
    - libpq API Reference
      - Database Connection Control Functions
        Description
        PQconnectdbParams
        PQconnectdb
        PQconninfoParse
        PQconnectStart
        PQerrorMessage
        PQsetdbLogin
        PQfinish
        PQreset
        PQstatus
      - Database Statement Execution Functions
        PQclear
        PQexec
        PQexecParams
        PQexecParamsBatch
        PQexecPrepared
        PQexecPreparedBatch
        PQfname
        PQgetvalue
        PQnfields
        PQntuples
        PQprepare
        PQresultStatus
      - Functions for Asynchronous Command Processing
        Description
        PQsendQuery
        PQsendQueryParams
        PQsendPrepare
        PQsendQueryPrepared
        PQflush
      - Functions for Canceling Queries in Progress
        PQgetCancel
        PQfreeCancel
        PQcancel
      - Example
      - Connection Characters
  - Psycopg-Based Development
  - Commissioning
  - Appendices
- Stored Procedure
- User Defined Functions
- PL/pgSQL-SQL Procedural Language
- Scheduled Jobs
  - PKG_SERVICE API
- Autonomous Transaction
- Logical Replication
  - Logical Decoding
    - Overview
    - Logical Decoding by SQL Function Interfaces
- Foreign Data Wrapper
- Materialized View
  - Materialized View Overview
  - Full Materialized View
  - Incremental Materialized View
- Resource Load Management
  - Overview
  - Resource Management Preparation
Performance Tuning Guide
Reference Guide
Common Faults and Identification Guide
- Common Fault Locating Methods
- Common Fault Locating Cases
  - Core Fault Locating
  - Permission/Session/Data Type Fault Location
  - Service/High Availability/Concurrency Fault Location
  - Table/Partition Table Fault Location
    - Table Size Does not Change After VACUUM FULL Is Executed on the Table
    - An Error Is Reported When the Table Partition Is Modified
  - File System/Disk/Memory Fault Location
  - SQL Fault Location
  - Index Fault Location
Source Code Parsing
FAQs
Glossary

SQLAllocHandle

Function

SQLAllocHandle is used to allocate environment, connection, statement, or descriptor handles. This function replaces the deprecated ODBC 2.x functions SQLAllocEnv, SQLAllocConnect, and SQLAllocStmt.

Prototype

SQLRETURN SQLAllocHandle(SQLSMALLINT   HandleType,
                         SQLHANDLE     InputHandle,
                         SQLHANDLE     *OutputHandlePtr);

Parameter

Table 1 SQLAllocHandle parameters

Keyword	Parameter Description
HandleType	Type of handle to be allocated by SQLAllocHandle. The value must be one of the following: - SQL_HANDLE_ENV (environment handle) - SQL_HANDLE_DBC (connection handle) - SQL_HANDLE_STMT (statement handle) - SQL_HANDLE_DESC (descriptor handle) The handle application sequence is: SQL_HANDLE_ENV > SQL_HANDLE_DBC > SQL_HANDLE_STMT. The handle applied later depends on the handle applied prior to it.
InputHandle	Existing handle to use as a context for the new handle being allocated. - If HandleType is SQL_HANDLE_ENV, this parameter is set to SQL_NULL_HANDLE. - If HandleType is SQL_HANDLE_DBC, this parameter value must be an environment handle. - If HandleType is SQL_HANDLE_STMT or SQL_HANDLE_DESC, this parameter value must be a connection handle.
OutputHandlePtr	Output parameter: Pointer to a buffer that stores the returned handle in the newly allocated data structure.

Return Value

SQL_SUCCESS indicates that the call succeeded.
SQL_SUCCESS_WITH_INFO indicates that some warning information is displayed.
SQL_ERROR indicates major errors, such as memory allocation and connection failures.
SQL_INVALID_HANDLE indicates that invalid handles were called. This value may also be returned by other APIs.

Precautions

If SQLAllocHandle returns SQL_ERROR when it is used to allocate a non-environment handle, it sets OutputHandlePtr to SQL_NULL_HDBC, SQL_NULL_HSTMT, or SQL_NULL_HDESC. The application can then call SQLGetDiagRec, with HandleType and Handle set to the value of IntputHandle, to obtain the SQLSTATE value. The SQLSTATE value provides the detailed function calling information.

Example

See ODBC - Examples.