### Install Pyrseas (Development Version)

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Clones the Pyrseas repository from GitHub and installs it locally for development.

```shell
git clone git://github.com/perseas/Pyrseas.git
cd Pyrseas
python setup.py install
```

--------------------------------

### Install Pyrseas using PGXN Client

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Installs the Pyrseas package using the PGXN client, which fetches packages from the PGXN repository.

```Shell
pgxn install pyrseas
```

--------------------------------

### Install Pyrseas (Latest Release)

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Installs the latest stable version of Pyrseas using pip.

```shell
pip install Pyrseas
```

--------------------------------

### Install Pyrseas (Unix/Linux - Superuser)

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Installs Pyrseas system-wide on Unix-like systems using administrative privileges.

```shell
sudo python setup.py install
```

--------------------------------

### Install Pyrseas (Windows - Administrator)

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Installs Pyrseas on Windows using administrative privileges.

```shell
python setup.py install
```

--------------------------------

### Clone Pyrseas Repository

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Fetches the Pyrseas source code from the GitHub repository.

```shell
git clone https://github.com/perseas/Pyrseas.git
```

--------------------------------

### Checkout Specific Pyrseas Release

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Switches the local repository to a specific tagged release of Pyrseas.

```shell
git checkout vn.n.n
```

--------------------------------

### Install Pyrseas using Pip

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Installs the Pyrseas package using the pip package installer. This is a common method for Python package management.

```Shell
sudo pip install Pyrseas
```

--------------------------------

### Update Pyrseas from Git

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Fetches the latest changes from the master branch of the Pyrseas repository.

```shell
git pull
```

--------------------------------

### Run Pyrseas Tests with tox

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

Command to execute the Pyrseas unit tests using tox, which handles virtual environment creation and dependency installation.

```bash
tox
```

--------------------------------

### SQL CREATE Statement Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/overview.rst

This snippet shows a basic SQL CREATE TABLE statement, which is the type of command Pyrseas utilities can generate or process.

```sql
CREATE TABLE example_table (
    id SERIAL PRIMARY KEY,
    name VARCHAR(255) NOT NULL
);
```

--------------------------------

### YAML Database Specification Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/overview.rst

This is an example of a YAML file format that Pyrseas tools might use to define or represent a database schema.

```yaml
tables:
  - name: users
    columns:
      - name: id
        type: SERIAL
        primary_key: true
      - name: username
        type: VARCHAR(50)
        nullable: false
```

--------------------------------

### Install Pyrseas Dependencies with Pip

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

Commands to install various Python dependencies required for Pyrseas testing using pip, the Python package installer.

```Shell
pip install psycopg
```

```Shell
pip install PyYAML
```

```Shell
pip install pytest
```

```Shell
pip install tox
```

--------------------------------

### dbtoyaml YAML Schema Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/dbtoyaml.rst

A sample of the YAML output format generated by dbtoyaml, illustrating schema, table, column, and constraint definitions.

```yaml
schema public:
  owner: postgres
  privileges:
  - postgres:
    - all
  - PUBLIC:
    - all
  table t1:
    check_constraints:
      t1_c2_check:
        columns:
        - c2
        expression: (c2 > 123)
    columns:
    - c1:
        not_null: true
        type: integer
    - c2:
        type: smallint
    - c3:
        default: 'false'
        type: boolean
    - c4:
        type: text
    foreign_keys:
      t1_c2_fkey:
        columns:
        - c2
        references:
          columns:
          - c21
          schema: s1 
          table: t2
    owner: alice
    primary_key:
      t1_pkey:
        columns:
        - c1
schema s1:
  owner: bob
  privileges:
  - bob:
    - all
  - alice:
    - all
  table t2:
    columns:
    - c21:
         not_null: true
         type: integer
    - c22:
         type: character varying(16)
    owner: bob
    primary_key:
      t2_pkey:
        columns:
        - c21
    privileges:
    - bob:
      - all
    - PUBLIC:
      - select
    - alice:
      - insert:
          grantable: true
      - delete:
          grantable: true
      - update:
          grantable: true
    - carol:
        grantor: alice
        privs:
        - insert

```

--------------------------------

### Clone Pyrseas Repository using Git

Source: https://github.com/perseas/pyrseas/blob/master/docs/devel.rst

This snippet shows how to clone the Pyrseas master repository from GitHub using Git. Ensure Git is installed before executing this command.

```Bash
git clone https://github.com/perseas/Pyrseas.git
```

--------------------------------

### ForeignKey Constraint Mapping Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/constraint.rst

Illustrates the structure of a foreign key segment as returned by the `to_map` method and expected by `ConstraintDict.from_map`. This includes columns, on_delete, on_update, and references details.

```Python
{
    't1_fgn_key1': {
        'columns': ['c2', 'c3'],
        'on_delete': 'restrict',
        'on_update': 'set null',
        'references': {
            'columns': ['pc2', 'pc1'],
            'schema': 's1',
            'table': 't2'
        }
    }
}
```

--------------------------------

### Extract Pyrseas Tarball

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Extracts the contents of a gzip-compressed tar archive for Pyrseas.

```shell
tar xzf Pyrseas-n.n.n.tar.gz
```

--------------------------------

### Extract Pyrseas ZIP Archive

Source: https://github.com/perseas/pyrseas/blob/master/docs/install.rst

Extracts the contents of a ZIP archive for Pyrseas.

```shell
unzip Pyrseas-n.n.n.zip
```

--------------------------------

### Pyrseas ForeignServer Methods

Source: https://github.com/perseas/pyrseas/blob/master/docs/foreign.rst

Represents a PostgreSQL foreign server. Includes methods for getting the identifier, converting to a map, and creating the server.

```Python
from pyrseas.dbobject.foreign import ForeignServer

# Example usage (assuming an instance 'server' exists)
# server.identifier()
# server.to_map()
# server.create()
```

--------------------------------

### Augmenter Schema and Table Configuration Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/configitems.rst

Illustrates how to define specific audit column configurations for individual tables within a schema. This allows for granular control over which augmentations are applied to which tables.

```yaml
augmenter:
  schema public:
    table t1:
      audit_columns: default
```

--------------------------------

### Pyrseas UserMapping Methods

Source: https://github.com/perseas/pyrseas/blob/master/docs/foreign.rst

Represents a mapping of a PostgreSQL user to a foreign server. Includes methods for getting the external key, identifier, and creating the mapping.

```Python
from pyrseas.dbobject.foreign import UserMapping

# Example usage (assuming an instance 'mapping' exists)
# mapping.extern_key()
# mapping.identifier()
# mapping.create()
```

--------------------------------

### Example Usage of aug_set_context

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Session-Variables

This SQL block demonstrates how to call the `aug_set_context` function to register application-level details into PostgreSQL session variables for auditing purposes.

```sql
BEGIN
  PERFORM aug_set_context('example_controller', 'example_action', '10.11.12.134', 'real_name', 'app_session_id');
END;
```

--------------------------------

### YAML Schema for Audit Examples Table

Source: https://github.com/perseas/pyrseas/wiki/AuditColumns

This YAML snippet defines the schema for the 'audit_examples' table, including columns for audit codes, names, and audit trail information like creation and modification timestamps and IP addresses. It also specifies the primary key and audit settings.

```YAML
schema example_schema:
  table audit_examples:
    columns:
    - audit_code:
        not_null: true
        type: character varying(5)
    - audit_name:
        not_null: true
        type: character varying(40)
    - created_by:
        not_null: true
        type: character varying(30)
    - created_date_time:
        not_null: true
        type: timestamp with time zone
    - created_by_ip:
        not_null: true
        type: inet
    - modified_by:
        not_null: true
        type: character varying(30)
    - modified_date_time:
        not_null: true
        type: timestamp with time zone
    - modified_by_ip:
        not_null: true
        type: inet
    primary_key:
      audit_examples_pkey:
        access_method: btree
        columns:
        - audit_code
    triggers:
      audit_examples_20_audit_full:
        events:
        - insert
        - update
        level: row
        procedure: fcl_owner.audit_full()
        timing: before
```

--------------------------------

### Augmenter Column Renaming Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/configitems.rst

Demonstrates how to specify an alternate name for a previously defined column within the Augmenter configuration. This allows for customization of column names used in database augmentations.

```yaml
augmenter:
  columns:
    modified_timestamp:
      name: last_update
```

--------------------------------

### Update Database Directly with SQL from YAML

Source: https://github.com/perseas/pyrseas/blob/master/docs/yamltodb.rst

This example demonstrates updating the 'mymovies' database directly using SQL statements generated by yamltodb from 'moviesdb.yaml'. It pipes the output to 'psql'.

```bash
yamltodb --update mymovies moviesdb.yaml
```

--------------------------------

### Trigger for Denormalizing Denorm Examples

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Denormalizations

This SQL trigger is set up to execute the `denorm_examples_denormalize` function before INSERT or UPDATE operations on the `denorm_examples` table. It ensures that denormalization logic is applied to the `denorm_examples` table.

```SQL
CREATE TRIGGER denorm_examples_40_denormalize
  BEFORE INSERT OR UPDATE
  ON example_schema.denorm_examples
  FOR EACH ROW
  EXECUTE PROCEDURE example_schema.denorm_examples_denormalize();
```

--------------------------------

### Generate SQL from YAML to Update Database

Source: https://github.com/perseas/pyrseas/blob/master/docs/yamltodb.rst

This example shows how to use yamltodb to generate SQL statements that update a database named 'mymovies' based on a YAML file 'moviesdb.yaml'.

```bash
yamltodb mymovies moviesdb.yaml
```

--------------------------------

### Clone Pyrseas Repository with Git

Source: https://github.com/perseas/pyrseas/wiki/contribute

This snippet demonstrates how to clone the Pyrseas project repository using the Git version control system. It provides two common methods for cloning: one using the git:// protocol for anonymous access and another using https:// for potentially authenticated access.

```git
git clone git://github.com/perseas/Pyrseas.git
```

```git
git clone https://github.com/perseas/Pyrseas.git
```

--------------------------------

### dbtoyaml Command Synopsis

Source: https://github.com/perseas/pyrseas/blob/master/docs/dbtoyaml.rst

The synopsis for the dbtoyaml command, showing its basic usage with options and the database name argument.

```bash
dbtoyaml [option...] dbname
```

--------------------------------

### dbaugment Command Line Syntax

Source: https://github.com/perseas/pyrseas/wiki/Augmenter

This snippet shows the proposed command-line arguments for the dbaugment tool. It takes a database name, a YAML file for extensions, and an optional configuration file.

```bash
dbaugment dbname extend.yaml --config config.file
```

--------------------------------

### Example SQL Statements for Database Schema Update

Source: https://github.com/perseas/pyrseas/blob/master/docs/yamltodb.rst

This is an example of SQL statements that might be generated by yamltodb to create and alter schema objects, including tables, columns, constraints, and ownership, based on a YAML specification.

```sql
CREATE SCHEMA s1;
ALTER SCHEMA s1 OWNER TO bob;
GRANT ALL ON SCHEMA s1 TO bob;
GRANT ALL ON SCHEMA s1 TO alice;
CREATE TABLE t1 (
    c1 integer NOT NULL,
    c2 smallint,
    c3 boolean DEFAULT false,
    c4 text);
ALTER TABLE t1 OWNER TO alice;
CREATE TABLE s1.t2 (
    c21 integer NOT NULL,
    c22 character varying(16));
ALTER TABLE s1.t2 OWNER TO bob;
GRANT ALL ON TABLE s1.t2 TO bob;
GRANT SELECT ON TABLE s1.t2 TO PUBLIC;
GRANT INSERT, DELETE, UPDATE ON TABLE s1.t2 TO alice WITH GRANT OPTION;
GRANT INSERT ON TABLE s1.t2 TO carol;
ALTER TABLE t1 ADD CONSTRAINT t1_c2_check CHECK (c2 > 123);
ALTER TABLE t1 ADD CONSTRAINT t1_pkey PRIMARY KEY (c1);
ALTER TABLE s1.t2 ADD CONSTRAINT t2_pkey PRIMARY KEY (c21);
ALTER TABLE t1 ADD CONSTRAINT t1_c2_fkey FOREIGN KEY (c2) REFERENCES s1.t2 (c21);
```

--------------------------------

### Get Audit IP Address Function (plpgsql)

Source: https://github.com/perseas/pyrseas/wiki/AuditColumns

This plpgsql function retrieves the audit IP address for the current session. It first attempts to get the IP address from a session variable 'audit_ip_address' and falls back to the client's IP address if the variable is not set.

```plpgsql
CREATE OR REPLACE FUNCTION example_schema.get_audit_ip_address()
  RETURNS inet AS
$BODY$
BEGIN
  RETURN COALESCE(get_session_variable('audit_ip_address', NULL)::inet, inet_client_addr());
END;
$BODY$
  LANGUAGE 'plpgsql' VOLATILE SECURITY DEFINER
  COST 100;
ALTER FUNCTION example_schema.get_audit_ip_address() SET search_path=example_schema, pg_temp;
REVOKE EXECUTE ON FUNCTION example_schema.get_audit_ip_address() FROM public;
```

--------------------------------

### Configure PostgreSQL Password File

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

Shows the creation of a PostgreSQL password file, essential for secure connections.

```bash
# Linux example:
# ~/.pgpass

# Windows example:
# %APPDATA%\postgresql\pgpass.conf
```

--------------------------------

### Create PostgreSQL User and Tablespaces

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

This snippet demonstrates how to create a PostgreSQL user with necessary privileges and define tablespaces for the Pyrseas project.

```sql
CREATE TABLESPACE ts1 LOCATION '<directory>';
CREATE TABLESPACE ts2 LOCATION '<directory>';
```

--------------------------------

### Pyrseas Conversion Class Methods

Source: https://github.com/perseas/pyrseas/blob/master/docs/conversion.rst

Demonstrates the to_map and create methods of the Pyrseas Conversion class, used for representing and creating PostgreSQL character set encoding conversions.

```Python
from pyrseas.dbobject.conversion import Conversion

# Example usage (assuming 'conversion_obj' is an instance of Conversion)
# conversion_map = conversion_obj.to_map()
# conversion_obj.create()
```

--------------------------------

### Print Version Information

Source: https://github.com/perseas/pyrseas/blob/master/docs/cmdargs.rst

Prints the program's name and version identifier and then exits.

```bash
pyrseas --version
```

--------------------------------

### Clone Pyrseas Repository

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

Command to clone the Pyrseas project repository from GitHub using Git.

```Shell
git clone git://github.com/perseas/Pyrseas.git
```

--------------------------------

### Define Copied Column in YAML Schema

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Denormalizations

An example YAML schema defining a table 'denorm_examples' with a column 'parent_other_column' that is copied from 'parent_table.other_column' via a foreign key 'child_parent_fk'.

```yaml
schema example_schema:
  table denorm_examples:
    columns:
    - child_id:
        default: nextval('example_schema.example_seq'::regclass)
        not_null: true
        type: integer
    - parent_id:
        not_null: true
        type: integer
    - parent_other_column:
        not_null: true
        type: character varying(20)
        copied_from:
            foreign_key: child_parent_fk
            column: other_column
    foreign_keys:
      child_parent_fk:
        columns:
        - parent_id
        on_delete: restrict
        on_update: restrict
        references:
          columns:
          - parent_id
          schema: example_schema
          table: parent_table
    indexes:
      child_parent_fk_i:
        access_method: btree
        columns:
        - parent_id
    primary_key:
      denorm_examples_pkey:
        access_method: btree
        columns:
        - child_id
```

--------------------------------

### SQL ALTER Statement Example

Source: https://github.com/perseas/pyrseas/blob/master/docs/overview.rst

This snippet demonstrates an SQL ALTER TABLE statement, used for modifying existing table structures, a common operation handled by Pyrseas.

```sql
ALTER TABLE example_table
ADD COLUMN description TEXT;
```

--------------------------------

### OperatorClass Methods (Python)

Source: https://github.com/perseas/pyrseas/blob/master/docs/operclass.rst

Demonstrates the usage of key methods for the OperatorClass, including retrieving external keys, identifiers, converting to a map, and creating operator classes.

```Python
from pyrseas.dbobject.operclass import OperatorClass

# Example usage (assuming an OperatorClass instance 'opc' exists)
# extern_key = opc.extern_key()
# identifier = opc.identifier()
# opc_map = opc.to_map()
# opc.create()
```

--------------------------------

### Show Help Information

Source: https://github.com/perseas/pyrseas/blob/master/docs/cmdargs.rst

Displays help information about the program's command-line arguments and then exits.

```bash
pyrseas -h
pyrseas --help
```

--------------------------------

### Get PostgreSQL Session Variable

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Session-Variables

This PL/pgSQL function retrieves the value of a PostgreSQL session variable prefixed with 'augmenter.'. It is used to access stored custom session variables.

```sql
CREATE OR REPLACE FUNCTION aug_get_session_variable(var_name character varying)
  RETURNS character varying AS
$BODY$
  BEGIN
    RETURN pg_catalog.current_setting('augmenter.' || var_name);
  END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
```

--------------------------------

### Pyrseas: INSTEAD OF Triggers and REVOKE/GRANT Commands

Source: https://github.com/perseas/pyrseas/blob/master/Changelog.rst

Adds support for `INSTEAD OF` triggers on views and eliminates the generation of spurious `REVOKE`/`GRANT` commands by `yamltodb`. Also removes `setuptools` from `setup.py`'s `install_requires`.

```SQL
-- Example of PostgreSQL INSTEAD OF trigger syntax
-- CREATE TRIGGER my_view_trigger
--   INSTEAD OF INSERT ON my_view
--   FOR EACH ROW EXECUTE FUNCTION my_view_trigger_func();
```

--------------------------------

### Calculate Denormalization in YAML

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Denormalizations

Defines a calculated denormalization for the 'total_value' column in the 'order_items' table, multiplying 'item_price' by 'qty'. This example shows how to define such a calculation directly within the schema definition.

```yaml
schema example_schema:
  table order_items:
    columns:
    - order_id:
        not_null: true
        type: integer
    - item_no:
        not_null: true
        type: integer
    - item_price:
        not_null: true
        type: numeric(10,2)
    - qty:
        not_null: true
        type: integer
    - total_value:
        type: numeric(10,2)
        calculated_from: {item_price} * {qty}
    primary_key:
      order_items_pkey:
        access_method: btree
        columns:
        - order_id
        - item_no
```

--------------------------------

### Pyrseas dbaugment Tool Prototype

Source: https://github.com/perseas/pyrseas/wiki/Augmenter

A prototype man page and a small proof-of-concept script for the dbaugment tool are being developed. The tool's output can be directed to standard output for piping or consumed internally by yamltodb.

```Python
dbaugment.py
```

--------------------------------

### Pyrseas ConversionDict Class Method

Source: https://github.com/perseas/pyrseas/blob/master/docs/conversion.rst

Illustrates the from_map method of the Pyrseas ConversionDict class, used for creating a collection of conversions from a map representation.

```Python
from pyrseas.dbobject.conversion import ConversionDict

# Example usage (assuming 'conversion_dict_data' is a dictionary)
# conversion_dict = ConversionDict.from_map(conversion_dict_data)
```

--------------------------------

### Get PostgreSQL Session Variable with Default

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Session-Variables

This PL/pgSQL function retrieves the value of a PostgreSQL session variable prefixed with 'augmenter.'. If the variable is not set, it returns a specified default value.

```sql
CREATE OR REPLACE FUNCTION aug_get_session_variable(var_name character varying, default_value character varying)
  RETURNS character varying AS
$BODY$
  BEGIN
    RETURN pg_catalog.current_setting('augmenter.' || var_name);
  EXCEPTION
    WHEN undefined_object THEN
      RETURN default_value;
  END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
```

--------------------------------

### Specify Repository Path

Source: https://github.com/perseas/pyrseas/blob/master/docs/cmdargs.rst

Specifies the path to a directory for metadata and static data files, or for an additional configuration file. Defaults to the current working directory if not specified.

```bash
pyrseas -r <path>
pyrseas --repository <path>
```

--------------------------------

### Create or Upgrade Database from YAML Specification using yamltodb

Source: https://github.com/perseas/pyrseas/blob/master/docs/overview.rst

The `yamltodb` utility takes a YAML specification file as input and generates a script of SQL CREATE or ALTER statements. This script can be used to create or upgrade a test or production database to match the input specification.

```bash
yamltodb < specification.yaml
```

--------------------------------

### Pyrseas Index Class Methods

Source: https://github.com/perseas/pyrseas/blob/master/docs/indexes.rst

Demonstrates methods for the Index class in Pyrseas, including key expressions, mapping to a dictionary, and operations for creating, altering, and dropping indexes.

```Python
from pyrseas.dbobject.index import Index

# Example usage (conceptual):
# index_obj = Index(schema='public', table='users', name='idx_email')
# key_expr = index_obj.key_expressions()
# index_map = index_obj.to_map()
# index_obj.create()
# index_obj.alter()
# index_obj.drop()
```

--------------------------------

### PL/pgSQL Function to Get Audit IP Address

Source: https://github.com/perseas/pyrseas/wiki/AuditColumns

A simple PL/pgSQL function that returns the IP address of the current client connected to the database. This is used in audit logging to track the origin of database operations.

```PL/pgSQL
language: plpgsql
    returns: inet
    source: "\nBEGIN
  RETURN inet_client_addr();
END;"
```

--------------------------------

### Extract to Directory for Version Control

Source: https://github.com/perseas/pyrseas/blob/master/docs/dbtoyaml.rst

Extracts database objects into a directory structure suitable for version control. The '-m' option enables multiple file output, and the output is placed in the 'movies/dbspec' directory.

```bash
dbtoyaml moviesdb -m movies/dbspec
```

--------------------------------

### YAML Specification for Database Augmentation

Source: https://github.com/perseas/pyrseas/blob/master/docs/dbaugment.rst

Defines database augmentations, including adding audit columns to tables. This example specifies a 'modified_only' audit column for the 'public.film' table and renames the default 'modified_timestamp' column to 'updated'.

```yaml
augmenter:
  columns:
    modified_timestamp:
      name: updated
schema public:
  table film:
    audit_columns: modified_only
```

--------------------------------

### Generate and Save SQL in a Single Transaction

Source: https://github.com/perseas/pyrseas/blob/master/docs/yamltodb.rst

This example shows how to generate SQL statements from 'dbtoyaml' output, process them with yamltodb in a single transaction ('-1'), specify the target database 'mymovies', and save the output to 'mymovies.sql'.

```bash
dbtoyaml devmovies | yamltodb -1 mymovies -o mymovies.sql
```

--------------------------------

### Run Pyrseas Tests with Pytest

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

Commands to execute Pyrseas unit tests using the pytest framework. This includes running all tests for a specific module, or running a single test case with a keyword filter.

```Shell
pytest-3 tests/dbobject/test_table.py
```

```Shell
pytest-3 tests/dbobject/test_trigger.py -k test_create_trigger
```

```Shell
pytest-3 tests/functional
```

--------------------------------

### PL/pgSQL Function to Get Audit User

Source: https://github.com/perseas/pyrseas/wiki/AuditColumns

Defines a PL/pgSQL function that retrieves the current audit user, falling back to the session user if no specific audit user is set. This function is crucial for audit trail logging.

```SQL
CREATE OR REPLACE FUNCTION example_schema.get_audit_user()
  RETURNS character varying AS
$BODY$
BEGIN
  RETURN COALESCE(get_session_variable('audit_user', NULL), SESSION_USER);
END;
$BODY$
  LANGUAGE 'plpgsql' VOLATILE SECURITY DEFINER
  COST 100;
ALTER FUNCTION example_schema.get_audit_user() SET search_path=example_schema, pg_temp;
REVOKE EXECUTE ON FUNCTION example_schema.get_audit_user() FROM public;
```

--------------------------------

### OperatorClassDict Loading (Python)

Source: https://github.com/perseas/pyrseas/blob/master/docs/operclass.rst

Shows how to load operator class data from a map into an OperatorClassDict instance.

```Python
from pyrseas.dbobject.operclass import OperatorClassDict

# Example usage (assuming a dictionary 'data_map' exists)
# opc_dict = OperatorClassDict.from_map(data_map)
```

--------------------------------

### Define Table Alias for Trigger Naming

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Configuration

This YAML example shows how to define an alias for a table to be used in generated trigger names. Instead of using the full table name, the alias simplifies the trigger name, especially for tables with long names.

```yaml
schema: example
  table example_customers:
    alias: cst
    audited: true
```

--------------------------------

### Generate YAML Specification from Database using dbtoyaml

Source: https://github.com/perseas/pyrseas/blob/master/docs/overview.rst

The `dbtoyaml` utility generates a YAML specification file from a PostgreSQL database. It can be used with the `--multiple-files` option to break down the specification into files corresponding to individual database objects, facilitating version control by allowing VCS diffs to highlight changes.

```bash
dbtoyaml --multiple-files
```

--------------------------------

### Denormalize Parent Column in Denorm Examples

Source: https://github.com/perseas/pyrseas/wiki/Augmenter-Denormalizations

This PostgreSQL function handles the denormalization of a parent table's column into a child table. It triggers on INSERT or UPDATE operations in the child table, copying data from the parent table based on a foreign key relationship. It ensures that changes in the parent table are reflected in the child table's denormalized column.

```plpgsql
CREATE OR REPLACE FUNCTION example_schema.denorm_examples_denormalize()
  RETURNS trigger AS
$BODY$
BEGIN
  -- Denormalize parent_other_column via child_parent_fk
  IF TG_OP = 'INSERT' THEN
    SELECT 
    other_column
    INTO 
    NEW.parent_other_column
    FROM example_schema.parent_table
    WHERE parent_id = NEW.parent_id;
  ELSIF TG_OP = 'UPDATE' AND ( 
      NEW.parent_id IS DISTINCT FROM OLD.parent_id OR 
      NEW.parent_other_column IS NULL) THEN
    SELECT 
    other_column
    INTO 
    NEW.parent_other_column
    FROM example_schema.parent_table
    WHERE parent_id = NEW.parent_id;
  ELSE
    NEW.parent_other_column = OLD.parent_other_column;
  END IF;
  RETURN NEW;
END;
$BODY$
  LANGUAGE plpgsql;
```

--------------------------------

### Pyrseas: Initial release features

Source: https://github.com/perseas/pyrseas/blob/master/Changelog.rst

Details the features supported in the initial release of Pyrseas, including dbtoyaml and yamltodb support for schemas, tables, sequences, constraints, and indexes.

```Python
# dbtoyaml and yamltodb support PostgreSQL schemas, tables,
# sequences, check constraints, primary keys, foreign keys, unique
# constraints and indexes.
```

--------------------------------

### AugmentDatabase.from_augmap Method (Python)

Source: https://github.com/perseas/pyrseas/blob/master/docs/augmentdb.rst

Initializes an AugmentDatabase instance from an augmentation map. This method allows for the configuration of schemas and augmenters to be loaded from a provided 'aug_map'.

```Python
def from_augmap(cls, aug_map):
    """Initializes an AugmentDatabase from an augmentation map."""
    pass
```

--------------------------------

### Specify Configuration File

Source: https://github.com/perseas/pyrseas/blob/master/docs/cmdargs.rst

Specifies an additional configuration file to be read and merged with existing configuration. The default behavior relies on other configuration sources.

```bash
pyrseas -c <config-file>
pyrseas --config <config-file>
```

--------------------------------

### Language Class Methods (Python)

Source: https://github.com/perseas/pyrseas/blob/master/docs/language.rst

Demonstrates methods for the Language class, including converting to a map, dropping the language, and creating the language. These methods are part of the pyrseas.dbobject.language module.

```Python
from pyrseas.dbobject.language import Language

# Example usage (assuming language object is instantiated)
# language.to_map()
# language.drop()
# language.create()
```

--------------------------------

### Pyrseas: New Utility 'dbaugment' and TTM-inspired Interface

Source: https://github.com/perseas/pyrseas/blob/master/Changelog.rst

Introduces a new experimental utility, `dbaugment`, for consistently adding objects to an existent database, focusing on adding audit columns to tables. Also presents a new interface to PostgreSQL inspired by *The Third Manifesto*.

```Python
# Conceptual Python code for dbaugment utility
# def add_audit_columns(table_name):
#     # ... logic to add audit columns

# Conceptual representation of TTM-inspired interface (Python)
# class TtmRelation:
#     def __init__(self, name):
#         self.name = name
#     # ... methods for relational operations
```

--------------------------------

### Load Text Search Configuration Dictionary from Map in Pyrseas

Source: https://github.com/perseas/pyrseas/blob/master/docs/textsearch.rst

Demonstrates loading a collection of text search configurations from a map (dictionary) into a TSConfigurationDict object. The from_map method facilitates this data loading.

```Python
from pyrseas.dbobject.textsearch import TSConfigurationDict

# Example usage (assuming 'config_map_data' is a dictionary representing configurations)
# config_dict = TSConfigurationDict.from_map(config_map_data)

```

--------------------------------

### Pyrseas IndexDict Class Method

Source: https://github.com/perseas/pyrseas/blob/master/docs/indexes.rst

Illustrates the from_map method for the IndexDict class in Pyrseas, used to create an IndexDict object from a dictionary representation.

```Python
from pyrseas.dbobject.index import IndexDict

# Example usage (conceptual):
# index_data = {
#     'index1': {'schema': 'public', 'table': 'users', 'name': 'idx_email'},
#     'index2': {'schema': 'public', 'table': 'products', 'name': 'idx_sku'}
# }
# index_dict_obj = IndexDict.from_map(index_data)
```

--------------------------------

### Force Password Prompt

Source: https://github.com/perseas/pyrseas/blob/master/docs/cmdargs.rst

Forces the program to prompt for a password before connecting to a database. Without this, libpq defaults (password file or PGPASSWORD) are used if authentication is required.

```bash
pyrseas -W
pyrseas --password
```

--------------------------------

### Extract Database to YAML File

Source: https://github.com/perseas/pyrseas/blob/master/docs/dbtoyaml.rst

Extracts a database schema into a single YAML file. The output is directed to standard output, which can be redirected to a file.

```bash
dbtoyaml moviesdb > moviesdb.yaml
```

--------------------------------

### Pyrseas: File Output and Configuration Management

Source: https://github.com/perseas/pyrseas/blob/master/Changelog.rst

Introduces changes to how Pyrseas handles file output, including using relative paths for `--multiple-files` and ensuring UTF-8 encoding for file output. Configuration files are now managed under the `pyrseas` directory.

```Python
# Conceptual Python code for file path handling and encoding
# import os
# output_path = os.path.join(base_dir, "..", "output_file.yaml")

# with open(output_path, 'w', encoding='utf-8') as f:
#     f.write(data)
```

--------------------------------

### Pyrseas Augmenter Round-tripping

Source: https://github.com/perseas/pyrseas/wiki/Augmenter

The Augmenter tool will support round-tripping by processing dbtoyaml output files, converting generated business logic back to declarations, or using the dbtoyaml output as its own input, only generating new or changed business logic.

```Python
# Example of processing dbtoyaml output
dbtoyaml_output = "..."
augmenter.process(dbtoyaml_output)

# Example of using dbtoyaml output as input
dbtoyaml_input = "..."
augmenter.process(dbtoyaml_input, use_as_input=True)
```

--------------------------------

### Configure Datacopy Schema and Tables

Source: https://github.com/perseas/pyrseas/blob/master/docs/configitems.rst

Specifies which tables to export from or import to the database. It includes schema names followed by lists of table names.

```YAML
datacopy:
  schema public:
  - t1
  - t2
  schema s1:
  - t3
```

--------------------------------

### Grant Permissions on Tablespace Directory (Windows)

Source: https://github.com/perseas/pyrseas/blob/master/docs/testing.rst

Windows command to grant full control permissions to the 'postgres' user on a specified directory, often needed for tablespaces.

```powershell
cacls <dir> /E /G postgres:F
```

--------------------------------

### Pyrseas: Added files for release via PGXN

Source: https://github.com/perseas/pyrseas/blob/master/Changelog.rst

Includes necessary files and configurations for releasing the Pyrseas project via the PostgreSQL Extension Network (PGXN).

```Python
# Added files for release via PGXN.
```